INTRODUCTION — Dermatitis is defined as an inflammation of the skin. The terms dermatitis include a wide variety of skin disorders, including atopic dermatitis (eczema), seborrheic dermatitis, contact dermatitis, latex dermatitis and allergy, and dyshidrotic dermatitis.
Depending upon the underlying cause, dermatitis can be a short-term or lifelong condition. In most cases, self-care measures and drug therapy can control the symptoms and prevent complications.
ATOPIC DERMATITIS (ECZEMA) — About 8 to 25 percent of people worldwide have atopic dermatitis (eczema). It often occurs in people who have other allergic disorders, such as asthma and allergic rhinitis (nasal inflammation caused by allergies, also known as hay fever). Family members are often affected.
Cause — The cause of eczema is unknown, but hereditary factors appear to play a strong role. The skin inflammation of atopic dermatitis results from an abnormal immune reaction that is triggered or worsened by exposure to allergens (substances that provoke an allergic reaction). About 85 percent of people with eczema have antibodies (proteins formed by the immune system) to foods or airborne allergens, such as dust mites and animal dander.
In children, eczema is often linked to food allergies. Common food allergens include milk, egg whites, wheat, corn, soybeans, and peanuts.
Symptoms — Most people with eczema develop their first symptoms before age five. Intense itching of the skin, redness, small bumps, and skin flaking are common (show picture 1). Scratching can cause additional skin inflammation, which can further worsen the itching. The itchiness may be more noticeable at nighttime. The skin is often dry, increasing the risk of skin injury with scratching. The skin lesions are therefore at risk for developing infection. Features of infection include pus-containing bumps in inflamed areas; prompt evaluation by a healthcare provider is recommended if this occurs
Features of eczema vary from one individual to another, and can change over time. Other features can include: Lichenification - Thick, leathery skin (usually as a result of frequent scratching) Icthyosis - Dry scales (show picture 2) Keratosis pilaris - Plugged hair follicles resulting in the development of small bumps, usually on the face, upper arms, and thighs Cheilitis - Inflammation around the lips Hyperlinear palms - Increased skin creasing on the palms Dennie-Morgan line - An extra fold of skin under the eye Periorbital darkening - Darkening of the skin around the eyes
Although eczema is usually confined to specific areas of the body, it may be widespread in severe cases: In young children, it typically occurs on the face, scalp, extremities, or trunk, and rarely occurs in the diaper area (show picture 3). In older children and adolescents, it is often accompanied by thickening and darkening of the skin, as well as scarring from repeated scratching. In adults, it commonly affects the back of the neck, the elbow creases, and the backs of the knees . Other affected areas may include the face, wrists, and forearms.
Diagnosis — There is no specific test used to diagnose eczema; diagnosis is usually based upon a person's history and the signs noted during a physical examination.
Factors that strongly suggest eczema include long-standing and recurrent itching, a personal or family history of allergic conditions, and an early age at onset. Other factors include a worsening of symptoms after exposure to certain triggers, and any of the skin findings noted above.
Allergy testing is usually reserved for people who have eczema in addition to features of asthma or allergic rhinitis. Allergy testing may also be recommended for children with suspected food allergies.
Treatment — Eczema is a chronic condition; it typically improves and then flares (worsens) periodically. Some people can have no symptoms for several years, only to have the disease return at a later time. It is not curable, although symptoms can be controlled with a variety of self-care measures and drug therapy. Eliminate exacerbating factors — Eliminating factors that worsen eczema can effectively control the symptoms. These factors may include frequent bathing and low-humidity environments (which can further dry the skin), emotional stress, rapid temperature changes, and exposure to certain chemicals and cleaning solutions. Common irritants include soaps and detergents, perfumes and cosmetics, wool or synthetic fibers, dust, sand, and cigarette smoke.
The following tips are recommended: Dust frequently and avoid placing upholstered furniture in the bedroom. Reducing exposure to house dust mites may reduce the severity of atopic dermatitis. Food allergies are relatively uncommon in adults, but may be a problem for a small percentage of infants and young children. However, changes to an infant or child's diet should be made only after consulting an allergy specialist because of the risk of eliminating a nutritionally important food group (eg, cow's milk, eggs, soy products). Emollients — Emollients are creams and ointments that moisturize the skin and can help relieve symptoms. The best emollients for people with atopic dermatitis are creams (such as Eucerin®, Cetaphil®, and Nutraderm®) and ointments (such as petroleum jelly, Aquaphor®, and Vaseline®). Emollients are most effective when applied immediately after bathing. Lotions should be avoided because they can worsen dry skin. Bathing — Lukewarm baths can hydrate and cool the skin, temporarily relieving the itching of eczema. Hot or long baths (greater than 10 to 15 minutes) and showers should be avoided since they can cause excessive drying. A mild soap or nonsoap cleanser (such as Cetaphil®) should be used sparingly. Application of an emollient immediately after bathing or showering prevents the drying that occurs through evaporation. Some experts recommend showers for their antibacterial effect, though individuals should determine which method is best for their situation. Topical steroids — Topical steroid creams and ointments are often effective for controlling mild to moderate atopic dermatitis. They are usually applied twice daily and help to reduce symptoms and moisturize the skin; non-medicated emollients can be resumed when symptoms resolve. Strong topical steroids may be needed to control severe flares of eczema; however, highly potent steroids should be used for only short periods of time to prevent thinning of the skin. Other topical treatments — Newer topical therapies for eczema include tacrolimus (Protopic®) and pemicrolimus (Elidel®). They are effective for controlling eczema in persons who have not improved with topical steroids, although do not work as quickly as topical steroids. They are useful in sensitive areas such as the face and groin, and can be used in children over age two. Due to safety concerns, it is recommended that these treatments be used only as instructed by a healthcare provider. Oral steroids — Oral steroids occasionally are used to treat a flare of chronic eczema, though should not be used on a regular basis because of side effects. Oral antihistamines — Oral antihistamines help relieve the itching of eczema and the accompanying eye irritation. The over-the-counter antihistamine diphenhydramine (Benadryl®), and other antihistamines, such as hydroxyzine and cyproheptadine, are most effective for eczema, although these drugs can cause drowsiness. The nonsedating antihistamines such as cetirizine (Zyrtec®) and loratadine (Claritin®) also may relieve symptoms, and loratadine is available without a prescription in the United States. Doxepin is an antidepressant that has antihistamine actions and may be recommended if other antihistamines are not helpful. Ultraviolet light therapy (phototherapy) — Ultraviolet light therapy (phototherapy) can effectively control atopic dermatitis. However, this therapy is expensive, may increase a person's risk for skin cancer, and is therefore recommended only for persons with severe eczema who do not respond to other treatments. Immunosuppressive drugs — Immunosuppressive drugs can effectively control severe eczema. These drugs include oral cyclosporine, tacrolimus, methotrexate, mycophenylate mofetil, and azathioprine. Treatment with these drugs can cause serious side effects, including an increased risk for infection, and their use is generally limited to persons who do not improve with other treatments.
SEBORRHEIC DERMATITIS — Seborrheic dermatitis causes overproduction of skin cells and sebum, the skin's natural oil. Seborrheic dermatitis usually occurs in areas of the body that have many oil-producing glands, including the scalp, face, upper chest, and back. It is most common during infancy; this is called cradle cap. Cradle cap usually resolves by 8 to 12 months of age.
Cause — The cause of seborrheic dermatitis is unknown, although it is known that an overgrowth of a normal skin yeast fungus occurs with this condition. It is not clear whether the fungus causes the flaking and redness or the increased flaking allows overgrowth of the fungus.
Symptoms — The symptoms of seborrheic dermatitis include redness, scaling, and itching of the affected skin. The dermatitis most often occurs on the scalp and face, especially on the eyebrows, the bridge and sides of the nose, and in the crease between the nose and lip (show picture 5). In men, seborrheic dermatitis is usually worse on the skin beneath mustaches and beards. Seborrheic dermatitis can also affect the chest, upper back, armpits, and pubic area, and the condition can affect the entire body in infants.
The term seborrhea refers to oiliness of the skin, without redness or scaling. Dandruff causes scalp scaling without redness, although it can commonly progress to seborrheic dermatitis of the scalp.
Diagnosis — There is no specific test for diagnosing seborrheic dermatitis. The diagnosis is usually based upon a person's history and the signs noted on physical examination. In rare cases, a skin biopsy (a collection of a small sample of skin tissue) may be necessary to confirm the diagnosis or rule out other conditions that mimic seborrheic dermatitis.
Treatment — The symptoms of seborrheic dermatitis can be effectively controlled with a combination of self-care measures and drug therapy. Washing and shampooing — Diligent washing and shampooing can control the symptoms of seborrheic dermatitis. Frequent washing counters the build-up of skin scales, and daily shampooing with a medicated shampoo controls scaling and itching on the scalp. For best results, the shampoo should be left in place for a few minutes before rinsing.
The growth of skin cells is slowed by shampoos that contain tar (Z-Tar®, Pentrax®, DHS tar®, Ionil T plus®, and T-Gel extra strength®), selenium sulfide (Selsun® and Exelderm®), and zinc pyrithione (Head and Shoulders®, Zincon®, and DHS zinc®). Shampoos containing antifungal medications (Nizoral®, Stieprox®) are quite effective. All of these shampoos can be used indefinitely. Topical steroids — Low potency topical steroids are usually the drugs selected first for the treatment of seborrheic dermatitis. These drugs are available in creams and lotions for the face and in alcohol-based liquids and aerosol sprays for the scalp. The topical steroids should be applied daily until the dermatitis improves; they can then be gradually discontinued. The lower potency steroid preparations are used, so that even prolonged use results in few, if any side effects. Topical antifungal drugs — The topical antifungal cream ketoconazole (Nizoral®) appears to be as effective as topical steroids for the treatment of seborrheic dermatitis. In cases of severe seborrheic dermatitis, treatment may include both topical steroids and topical antifungal drugs.
CONTACT DERMATITIS — Contact dermatitis refers to dermatitis that is caused by direct contact of the skin with a substance. The substance can be an allergen (a substance that provokes an immune reaction) or an irritant (a substance that directly damages the skin). The dermatitis results from contact with an irritant in about 80 percent of people with contact dermatitis.
Irritant contact dermatitis — Irritant contact dermatitis occurs when the skin comes in direct contact with a substance that physically, mechanically, or chemically irritates the skin.
Cause — The skin becomes inflamed when the normal skin barrier is irritated. The most common cause are products used on a daily basis, including soap, cleansers, and rubbing alcohol. Persons with other skin conditions, dry skin, and light-colored or "fair" skin are at greatest risk, although anyone can develop irritant dermatitis.
Symptoms — Mild irritants cause redness, dryness, and fissures (small cracks), with itching. Strong irritants cause swelling, oozing, tenderness, and blisters (show picture 6).
Irritant contact dermatitis most commonly affects the hands, often beginning in the area between the fingers. It can also affect the face, especially the eyelids.
Diagnosis — The diagnosis of irritant contact dermatitis is usually based upon a person's history and the physical examination. In some cases, a patch test (applying a small amount of the possible irritant to the skin) may be recommended to determine if the dermatitis is caused by an allergy.
Treatment — The treatment of irritant contact dermatitis helps to restore the normal skin barrier and protecting the skin from additional injury by the irritant. Reducing exposure to known irritants is essential. In some cases, simply reducing the use of soap and using emollient creams or ointment alleviates symptoms. Wearing gloves when working with irritants may help as well.
In more severe cases, topical steroids may be used. These are most effective when applied and covered with a barrier, such as plastic wrap, a gauze dressing, cotton gloves, or petroleum jelly. Oral steroids are not used for the long-term treatment of irritant contact dermatitis; however, they may be used briefly to treat severe dermatitis.
Allergic contact dermatitis — Allergic contact dermatitis occurs in some individuals when the skin comes in direct contact with an allergen. This activates the body's immune system, which triggers inflammation. Anyone can experience allergic contact dermatitis. Allergic contact dermatitis can occur when someone is newly exposed to a product, but can also occur after years of use.
Common allergens — Poison ivy, poison oak, and poison sumac are the most common contact allergens. (See "Patient information: Poison ivy"). Other common allergens include nickel (show picture 7) in jewelry, perfumes and cosmetics, components of rubber, nail polish, and chemicals in shoes (both leather and synthetic, show picture 8). Allergic contact dermatitis can also be triggered by certain medications, including topical hydrocortisone, topical antibiotics, benzocaine, and thimerosol.
Symptoms — Symptoms include intense itching and a red rash that develops quickly. The rash is usually limited to areas that were in direct contact with the allergen, but a rash can appear in other areas of the body if the allergen was transferred to those areas on a person's hands (show picture 9). Washing the allergen away with soap and water can usually prevent this spread.
The rash typically appears within 12 to 48 hours of exposure to the allergen, although in some cases it may not appear for up to two weeks. Less commonly, the rash persists for months or years, which makes it difficult to identify what caused the reaction.
Diagnosis — The diagnosis of allergic contact dermatitis is based upon a person's history and the signs noted during a physical examination. An improvement of symptoms after eliminating exposure to the suspected allergen supports the diagnosis. Patch testing (applying a small amount of the possible irritant to the skin) can be helpful in identifying the allergen.
Treatment — Allergic contact dermatitis usually resolves within two to four weeks after a person's exposure to the allergen stops. Several measures can minimize symptoms during this time and can help control symptoms in people who have chronic allergic contact dermatitis.
Whenever possible, identify and stop all exposure to the allergen. Topical steroids can alleviate inflammation. Calamine lotion may relieve mild symptoms.
For more severe symptoms, oral drugs, including steroids (such as prednisone) and antihistamines, may be recommended. Wet-to-dry compresses help dry out oozing skin and cool the skin, relieving severe itching. Wet-to-dry compresses can be easily made and applied at home as follows: Dampen a thin piece of fabric (such as one layer of a cotton or linen sheet) in water or a mixture of water and aluminum acetate (Burow's solution) Apply the dampened fabric to the affected skin Allow the fabric to dry over 15 to 30 minutes Remove the dry fabric gently Repeat the procedure several times
LATEX DERMATITIS — Latex is a fluid produced by rubber trees that is processed into a variety of products, including gloves, balloons, and condoms. In some individuals, exposure to these products and others (such as rubber bands, erasers, feeding nipples, pacifiers) can cause a contact dermatitis that is either an irritant or allergic reaction. Less commonly, a person can develop a potentially life threatening allergic reaction to latex.
Irritant dermatitis — Irritant dermatitis can occur while wearing latex gloves. It usually occurs on the hands of people who wear latex or other rubber gloves; the latex acts as an irritant and the gloves trap moisture against the skin. The skin dries out when the gloves are removed, leading to the dermatitis.
The symptoms of irritant rubber or latex dermatitis include redness and itching on the skin. There may also be dryness and cracking. Symptoms usually occur within 12 to 36 hours of contact with a latex product. Treatment involves avoiding use of any latex-containing products.
Latex allergy — Latex can trigger allergic contact dermatitis. The skin reaction caused by a latex allergy does not differ significantly from that of irritant latex dermatitis.
Some people with latex allergy have severe allergic reactions to latex, including swelling, sneezing, and wheezing. Rarely, anaphylaxis can occur, which causes life-threatening difficulty with breathing. Typically, the most severe allergic reactions occur during procedures when latex comes into contact with mucous membranes (such as in the mouth, vagina, or during surgical procedures). However, some people are so sensitive that severe reactions can occur with even brief contact. (See "Patient information: Anaphylaxis").
Latex allergy is most common among people who have undergone many surgeries and who have other allergic conditions. Latex allergy is also common among health care workers and workers in the latex industry, particularly those who have atopic dermatitis or a history of other types of allergies (such as allergic rhinitis or asthma).
Latex can become aerosolized (often from powder in gloves) and cause nasal symptoms and asthma in sensitized individuals. Some people with latex allergy may also develop reactions to certain foods, including avocado, kiwi, banana, and chestnuts.
Diagnosis — In most cases, the diagnosis of latex allergy is based upon a person's history of exposure. The more serious type of latex allergy causes an immediate onset of hives, nasal symptoms, swelling, or wheezing after latex exposure. Some of these individuals may need to see a dermatologist or allergist for specialized skin patch tests and blood testing to verify the latex allergy.
Treatment — The primary mode of treatment for latex allergy is to avoid all latex-containing products. Non-latex examination gloves are widely available, and use of glove liners may also be an effective approach. Natural membrane (sometimes called sheep skin) condoms may be used in place of latex condoms. Natural membrane condoms are effective for preventing pregnancy, but do not protect against transmission of sexually transmitted diseases such as HIV, gonorrhea, and chlamydia.
Those with serious latex allergy should wear a bracelet, necklace, or similar alert tag at all times. If a reaction occurs and the person is too ill to explain their condition, this will help responders get the proper care for the person as quickly as possible. This measure is especially important in children.
The alert tag should include a list of known allergies, as well as the name and phone number of an emergency contact. One device, Medic Alert®, provides a toll-free number that emergency medical workers can call to find out a person's medical history, list of medications, family emergency contact numbers, and healthcare provider names and numbers.
Persons with a latex allergy should inform their doctors, dentists, and other health care providers about the allergy. These individuals also may be advised to carry an anaphylaxis kit (containing epinephrine that can be injected under the skin) as a precautionary measure. Because latex allergy is common among people with spina bifida, doctors often recommend that people with this condition undergo a screening for latex allergies before any medical procedures are performed. (See "Patient information: Use of an epinephrine autoinjector").
DYSHIDROTIC DERMATITIS — Dyshidrotic dermatitis (also called pompholyx or dyshidrosis) is an intensely itching chronic, recurring dermatitis of unknown cause that typically involves the palms, soles, and fingers. Most people experience acute episodes of intense itching on the palms and/or soles that progress to multiple small vesicles (fluid-filled bumps), which peel off over one to two weeks, leaving cracks in the skin that slowly resolve (show picture 10). Recurrent episodes alternating with symptom-free periods are common.
Medium strength to potent topical steroids can control outbreaks in mild cases. Occasionally, brief courses of oral steroids are necessary to control symptoms. Local treatments with ultraviolet light therapy are helpful in people who have not responded to other measures.
NUMMULAR DERMATITIS — Nummular dermatitis causes intensely itchy patches of skin, with redness, small bumps, skin flaking, slight crusting, and some serous oozing on close inspection. A person may have as few as one lesion or as many as 20 to 50 lesions. Each lesion tends to be circular, measuring 2 to 10 cm in diameter.
Lesions are usually on the trunk and lower extremities, and the head is generally spared. The onset is usually spontaneous, and the cause often cannot be identified; some people may have exposures to drying or irritating substances (eg, excessive water exposure, chlorine, soaps).
A potent topical steroid ointment is the treatment of choice for nummular dermatitis. Systemic steroids in short courses are occasionally required. It may be helpful to avoid irritants, if they can be identified. Skin moisturization is an important part of the management of nummular dermatitis; a rich moisturizing cream should be applied immediately after bathing.
SUMMARY Dermatitis is defined as an inflammation of the skin; there are several different types of dermatitis. Atopic dermatitis (eczema) is a common chronic condition that causes skin to become red, itchy, and dry. People with other allergies are more likely to develop the condition; the diagnosis is often based on this as well as examination of the skin. Treatment includes avoiding things that make symptoms worse (such as dry air and irritating fabrics) and applying creams or ointments to soothe the itchy rash. (See "Atopic dermatitis (eczema)" above). Seborrheic dermatitis causes overproduction of skin cells and oil; it is most common in infants (cradle cap). This type of dermatitis causes redness, itching, and scaling of the skin, and often affects the face and scalp; it is diagnosed based on a person's history and examination of the skin. Symptoms can be controlled by washing the skin and hair carefully and applying creams to relieve itching and redness. (See "Seborrheic dermatitis" above). Irritant contact dermatitis is a reaction caused by contact with a substance that is irritating to the skin, such as a soap or cleanser. This can make the skin red, itchy, and dry. Persons with other skin conditions, dry skin, and light-colored or "fair" skin are at greatest risk, although anyone can develop irritant dermatitis. Diagnosed may be done by testing the skin's reaction to a very small amount of the irritant; avoiding the substance usually relieves symptoms, but medicated creams may be prescribed in severe cases. (See "Irritant contact dermatitis" above). Allergic contact dermatitis occurs when the skin touches a substance that not only irritates, but actually causes an allergic reaction (such as with poison ivy). A rash appears where contact occurred, and usually resolves on its own if the substance is avoided; creams or compresses may be used to relieve itching and inflammation. (See "Allergic contact dermatitis" above). Latex dermatitis is caused by contact with latex (eg, latex gloves). Some people have a serious, life-threatening allergy to latex, and must be very careful to avoid it. (See "Latex dermatitis" above). Dyshidrotic dermatitis is a condition that causes intense itching and bumps, often on the palms of the hands and soles of the feet; steroids that are applied to the skin or taken as a pill are often used to treat this condition. (See "Dyshidrotic dermatitis" above).
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
National Institute on Arthritis and Musculoskeletal and Skin Diseases
(www.niams.nih.gov/hi/index.htm)
American Academy of Dermatology
(www.aad.org)
American Academy of Allergy, Asthma and Immunology
(www.aaaai.org)
EczemaNet
(www.skincarephysicians.com/eczemanet/)
National Eczema Association for Science and Education
(www.eczema-assn.org)
[1-3]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Jones, SM, Sampson, HA. The role of allergens in atopic dermatitis. Clin Rev Allergy 1993; 11:471.
2. Charman, C. Clinical evidence: atopic eczema. BMJ 1999; 318:1600.
3. Agner, T. Noninvasive measuring methods for the investigation of irritant patch test reactions. A study of patients with hand eczema, atopic dermatitis and controls. Acta Derm Venereol Suppl (Stockh) 1992;
Tuesday, October 9, 2007
ASTHMA Patient information: Trigger avoidance in asthma
INTRODUCTION — Asthma is a chronic lung condition that causes inflammation and constriction of the airways and difficulty breathing. Asthma attacks, or worsening of asthma symptoms, can occur after exposure to factors known as triggers (show table 1).
Not all patients with asthma have the same triggers. Finding out which factors trigger an attack and taking steps to avoid the triggers are important parts of good asthma management.
IDENTIFYING AND MANAGING TRIGGERS — Careful attention to the pattern of asthma symptoms is an important part of identifying triggers. For example, if symptoms occur primarily at home, something in that environment may be involved. If symptoms flare in the spring or fall, an outdoor allergy is more likely to blame.
Additional information about possible asthma triggers can sometimes be gained by using blood tests or skin tests to see if a patient is sensitive (or allergic) to a particular substance.
Once asthma triggers have been identified, the patient has several options: Avoid the trigger entirely. Limit exposure to the trigger if it cannot be completely avoided. If a trigger is encountered in a predictable manner, consult with a healthcare provider about taking an extra dose of medicine before exposure to the trigger. Immunotherapy (allergy shots) can sometimes be helpful.
INDOOR TRIGGERS — Allergens are substances that can produce an allergic reaction and are major triggers in many people with asthma. Sensitivity to indoor allergens is especially common in asthmatics. The most common indoor allergens that affect asthmatics are dust mites, mold, animal danders, and cockroaches. The bedroom of the asthmatic person should be given special consideration because the greatest number of hours are typically spent there. However, to be effective, measures must be made to reduce allergens throughout the entire home.
Dust mites — Dust mites are microscopic organisms that are present in most households. They avoid light and absorb humidity from the atmosphere (ie, they do not drink). Mites may live in bedding, sofas, carpets, or any woven material if the humidity is high enough.
Measures that help limit exposure to dust mites are detailed in Table 2 and include (show table 2) : Create a physical barrier to the source of the mites by covering pillows and mattresses with plastic or another impermeable fabric covers. A potential source of confusion when purchasing bedding covers is the availability of "hypoallergenic" unbleached or organic cotton bedding covers. These do not limit the passage of dust mites and are intended for people who have contact sensitivities to fabric dyes. Decrease the population of dust mites in the home by washing bedding in hot water and removing carpets and stuffed toys; these measures help to reduce nesting areas for mites. Control humidity. Mites thrive in humid environments. Opening windows in dry climates and using air conditioning in humid ones decreases humidity in the home and reduces the number of mites. Moving to or spending more time on upper floors of buildings may help, as upper floors tend to be less humid than lower floors or basements. Household humidity should be below 50 percent if possible. Inexpensive humidity monitors can be purchased at most hardware stores.
Mold — Mold spores can trigger asthma in allergic patients. Mold thrives in damp environments. Area such as air conditioning vents, water traps, refrigerator drip trays, shower stalls, leaky sinks, and damp basements are particularly vulnerable to mold growth if not cleaned regularly.
General measures to reduce mold exposure include the quick repair of any plumbing leaks, removal of bathroom carpeting which is exposed to steam and moisture, and scouring of sinks and tubs at least every four weeks with dilute bleach (1 ounce diluted in one quart of water); mold thrives on soap film that covers tiles and grout. In addition, indoor garbage pails should be regularly disinfected, and an electric dehumidifier should be used to remove moisture from the basement. Old books, newspapers, clothing, and bedding should not be stored in the home. Water damaged carpets should be thrown out because eliminating mold is difficult or impossible, even with thorough cleaning. For an important note about the use of bleach by people with asthma, see below (see "Irritants" below).
Animal danders — Asthma can be triggered by proteins from the "dander," saliva, and urine of common house pets such as cats and dogs. Other warm-blooded animals, such as rodents, birds, and ferrets can also trigger asthma in an allergic individual. Pets without feathers or fur, such as reptiles, turtles, and fish, rarely cause allergy, although deposits of fish food that may build up under the covers of fish tanks are an excellent source of food for dust mite colonies.
Animal dander is made up of the dead skin cells or scales (like dandruff) that are constantly shed by animals. Any breed of dog and cat is capable of being allergenic, although the levels given off by individual animals may vary to some degree. In cats, the protein that causes most people's allergies is found in the cat's saliva, skin glands, and urinary/reproductive tract. Accordingly, short-haired cats are not necessarily less allergenic than long-haired animals, and furless cats give off similar amounts of allergen as furred cats.
If a person with asthma is found to be allergic to a pet, the pet should be removed from the home. Limiting an animal to a certain area in the house is not effective because some allergens are carried on clothing or spread in the air. Once a pet has left a home, careful cleaning of carpets, sofas, curtain, and bedding must follow. This is particularly true for cat allergens, as they are "sticky" and adhere to a variety of indoor surfaces. Even after a cat has been removed from a home and it has been thoroughly cleaned, it can take months for levels of cat allergen to drop . For this reason, it may take months for the allergic person's symptoms to fully reflect the absence of the pet.
If it is not possible to remove the animal, measures can be taken to decrease exposure to the animal dander (show table 3), although none of these methods is as effective as removing the animal.
Cockroaches — Cockroach droppings contain allergens that have been shown to trigger asthma in sensitive individuals. Cockroaches thrive in warm environments with easily accessible food and water. Unfortunately, efforts to control cockroach populations in infested areas are often less than successful. Still, certain measures should be tried, including: Using multiple baited traps or poisons Removing garbage and food waste promptly from the home Washing dishes and cooking utensils immediately after use Removing cockroach debris quickly Eliminating any standing water from leaking faucets or drains
The role of air filters — Air filtering devices, including HEPA and other mechanical filters as well as electrostatic filters, are widely advertised and can be quite costly. These may be marketed as components of heating or cooling systems, as individual units for use in a room or area, or as units that are worn by individuals. None of these filtration devices have been scientifically proven to have a significant impact on asthma symptoms.
One possible explanation for this is that although these devices may clean the air, allergen levels cannot be effectively reduced unless measures are taken to eliminate their source. Thus, air filtration may be a useful adjunct to the measures described above, although we advise directing financial resources and efforts primarily towards eliminating sources of allergens.
CONTROLLING OTHER ASTHMA TRIGGERS — In addition to indoor allergens, other factors may be identified as asthma triggers.
Respiratory infections — Infections that cause airway inflammation can trigger asthma, including colds, influenza (flu), bronchitis, ear infections, sinus infections, and pneumonia. An asthma attack that occurs along with a respiratory infection may be more severe than one that occurs at other times. (See "Patient information: Influenza" and see "Patient information: Pneumonia in adults" and see "Patient information: The common cold in adults").
To reduce the risk of a serious flare related to respiratory infection, a person with asthma should: Call a healthcare provider at the first sign of an infection. Get a flu shot once a year. Get a pneumonia vaccine (if needed based on other risk factors) Wash hands frequently, especially when in contact with an infected person, and avoid contact with infected people when possible. Use treatments prescribed for symptoms, such as nasal steroids and decongestants.
Allergies to food and medicine — Allergy to foods, especially foods containing sulfites (potatoes, shrimp, dried fruit, beer, wine) may trigger asthma in sensitive individuals. A food diary, listing all food and drink and chronicling asthma symptoms, may help isolate sensitivity to a particular food. If a sulfite allergy has been identified, the patient should be sure to read food labels to make sure sulfites are not present.
Sensitivity to medications can also trigger asthma. In particular, aspirin, some other anti-inflammatory drugs such as ibuprofen (Advil®, Motrin®) and naproxen (Aleve®, Anaprox®) and certain beta blocker heart medicines may cause an attack in certain individuals. Acetaminophen (Tylenol®) does not cause symptoms in most aspirin-sensitive patients.
Outdoor allergens — Asthma symptoms that worsen outdoors at certain times of year are likely to be triggered by an allergy to pollen or other plant material. Affected individuals should stay indoors as much as possible during the season when their asthma tends to flare and keep windows closed. Patients should also try to avoid cutting grass, digging around plants, or other outdoor activities that seem to worsen asthma symptoms.
Irritants — A variety of irritants can trigger asthma. Irritants can be found inside or outside, and include: Cigarette smoke and ashes — A person with asthma should never smoke, smoking should not be allowed in the person's home, and second-hand smoke should be avoided whenever possible. (See "Patient information: Smoking cessation"). Aerosol sprays, perfumes — Non-aerosol products should be used, and exposure to offending perfumes avoided. Fireplace smoke and cooking odors — Wood-burning stoves, fireplaces, and pellet stoves should not be used, and cooking areas should be well ventilated. Air pollution, car exhaust, gas fumes — Patients should avoid unnecessary exposure to car exhaust, and outdoor exercise should be avoided when pollution levels are high.
Chemicals — Industrial or occupational exposure to chemicals is responsible for about 15 percent of cases of asthma. If symptoms tend to flare in a workplace where chemicals are in use, the patient and healthcare provider can discuss strategies to limit exposure.
If possible, patients whose asthma is triggered by strong odors should also avoid the use of chlorine and bleach-based cleaning products. If these cleaners are needed to control the growth of mold in the home, efforts should be made to ventilate the area thoroughly during and after use, and if possible, have a non-asthmatic person perform the cleaning.
Menstrual cycle — Worsening of asthma symptoms before or during menstruation has been reported in 20 to 40 percent of women with asthma. The reason for this phenomenon is unclear. Women with hormonally-triggered asthma tend to have more severe asthma than women whose asthma is unaffected by hormonal levels.
The optimal management of menstrual-associated asthma flares has not been determined, although women with a history of this problem are advised to increase their medication if necessary and avoid other potential asthma triggers.
Physical activity — Although exercise can trigger asthma in certain people, it should not be avoided. Exercise strengthens the cardiovascular system and may decrease sensitivity to asthma triggers. To minimize the effects of this trigger, asthmatics should: Take one or 2 puffs from an albuterol inhaler 5 minutes before beginning exercise Start any new exercise regime slowly, gradually building strength and endurance. Warm up gradually at the beginning of each exercise session. Take all medications on schedule. Avoid exercising outdoors in extremely cold weather and cover the mouth and nose with a scarf to help warm the inspired air when temperatures are low.
SUMMARY Asthma is a chronic lung condition that causes inflammation and constriction of the airways and difficulty breathing. Asthma attacks, or worsening of asthma symptoms, can occur after exposure to factors known as triggers (show table 1). Once asthma triggers have been identified, the patient has several options: avoid the trigger entirely, limit exposure to the trigger if it cannot be completely avoided, consult with a healthcare provider about taking an extra dose of medicine before exposure to the trigger, or consider immunotherapy (allergy shots), which can sometimes be helpful. Allergens are substances that can produce an allergic reaction in people who are sensitive (allergic) to them. Sensitivity to indoor allergens is especially common in asthmatics. The most common indoor allergens that affect asthmatics are dust mites, mold, animal danders, and cockroaches. In addition to indoor allergens, other factors may be identified as asthma triggers, including respiratory infections (colds, flu), allergies to food or medicines, outdoor allergens (pollen, grasses), irritants (cigarette smoke, aerosols, wood smoke, car exhaust), chemicals in the home or workplace, a woman's menses, or physical activity.
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. The National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
American Academy of Allergy, Asthma, and Immunology
(www.aaaai.org)
National Heart, Lung, and Blood Institute
(www.nhlbi.nih.gov/)
National Lung Health Education Program
(www.nlhep.org)
American Lung Association
(www.lungusa.org)
American College of Allergy, Asthma, and Immunology
(allergy.mcg.edu/)
[1-5]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. National Asthma Education and Prevention Program. Expert Panel Report: Guidelines for the Diagnosis and Management of Asthma Update on Selected Topics--2002. J Allergy Clin Immunol 2002; 110:S141.
2. Platts-Mills, TA, Vervloet, D, Thomas, WR, et al. Indoor allergens and asthma: report of the Third International Workshop. J Allergy Clin Immunol 1997; 100:S2.
3. Sporik, RB, Holgate, ST, Platts-Mills, TAE, Cogswell, J. Exposure to house dust mite allergen (Der p I) and the development of asthma in childhood: A prospective study. N Engl J Med 1990; 323:502.
4. Wood, RA, Johnson, EF, Van Natta, ML, et al. A placebo-controlled trial of a HEPA air cleaner in the treatment of cat allergy. Am J Respir Crit Care Med 1998; 158:115.
5. Cates, CJ, Jefferson, TO, Bara, AI, Rowe, BH. Vaccines for preventing influenza in people with asthma. Cochrane Database Syst Rev 2004; :CD000364.
Not all patients with asthma have the same triggers. Finding out which factors trigger an attack and taking steps to avoid the triggers are important parts of good asthma management.
IDENTIFYING AND MANAGING TRIGGERS — Careful attention to the pattern of asthma symptoms is an important part of identifying triggers. For example, if symptoms occur primarily at home, something in that environment may be involved. If symptoms flare in the spring or fall, an outdoor allergy is more likely to blame.
Additional information about possible asthma triggers can sometimes be gained by using blood tests or skin tests to see if a patient is sensitive (or allergic) to a particular substance.
Once asthma triggers have been identified, the patient has several options: Avoid the trigger entirely. Limit exposure to the trigger if it cannot be completely avoided. If a trigger is encountered in a predictable manner, consult with a healthcare provider about taking an extra dose of medicine before exposure to the trigger. Immunotherapy (allergy shots) can sometimes be helpful.
INDOOR TRIGGERS — Allergens are substances that can produce an allergic reaction and are major triggers in many people with asthma. Sensitivity to indoor allergens is especially common in asthmatics. The most common indoor allergens that affect asthmatics are dust mites, mold, animal danders, and cockroaches. The bedroom of the asthmatic person should be given special consideration because the greatest number of hours are typically spent there. However, to be effective, measures must be made to reduce allergens throughout the entire home.
Dust mites — Dust mites are microscopic organisms that are present in most households. They avoid light and absorb humidity from the atmosphere (ie, they do not drink). Mites may live in bedding, sofas, carpets, or any woven material if the humidity is high enough.
Measures that help limit exposure to dust mites are detailed in Table 2 and include (show table 2) : Create a physical barrier to the source of the mites by covering pillows and mattresses with plastic or another impermeable fabric covers. A potential source of confusion when purchasing bedding covers is the availability of "hypoallergenic" unbleached or organic cotton bedding covers. These do not limit the passage of dust mites and are intended for people who have contact sensitivities to fabric dyes. Decrease the population of dust mites in the home by washing bedding in hot water and removing carpets and stuffed toys; these measures help to reduce nesting areas for mites. Control humidity. Mites thrive in humid environments. Opening windows in dry climates and using air conditioning in humid ones decreases humidity in the home and reduces the number of mites. Moving to or spending more time on upper floors of buildings may help, as upper floors tend to be less humid than lower floors or basements. Household humidity should be below 50 percent if possible. Inexpensive humidity monitors can be purchased at most hardware stores.
Mold — Mold spores can trigger asthma in allergic patients. Mold thrives in damp environments. Area such as air conditioning vents, water traps, refrigerator drip trays, shower stalls, leaky sinks, and damp basements are particularly vulnerable to mold growth if not cleaned regularly.
General measures to reduce mold exposure include the quick repair of any plumbing leaks, removal of bathroom carpeting which is exposed to steam and moisture, and scouring of sinks and tubs at least every four weeks with dilute bleach (1 ounce diluted in one quart of water); mold thrives on soap film that covers tiles and grout. In addition, indoor garbage pails should be regularly disinfected, and an electric dehumidifier should be used to remove moisture from the basement. Old books, newspapers, clothing, and bedding should not be stored in the home. Water damaged carpets should be thrown out because eliminating mold is difficult or impossible, even with thorough cleaning. For an important note about the use of bleach by people with asthma, see below (see "Irritants" below).
Animal danders — Asthma can be triggered by proteins from the "dander," saliva, and urine of common house pets such as cats and dogs. Other warm-blooded animals, such as rodents, birds, and ferrets can also trigger asthma in an allergic individual. Pets without feathers or fur, such as reptiles, turtles, and fish, rarely cause allergy, although deposits of fish food that may build up under the covers of fish tanks are an excellent source of food for dust mite colonies.
Animal dander is made up of the dead skin cells or scales (like dandruff) that are constantly shed by animals. Any breed of dog and cat is capable of being allergenic, although the levels given off by individual animals may vary to some degree. In cats, the protein that causes most people's allergies is found in the cat's saliva, skin glands, and urinary/reproductive tract. Accordingly, short-haired cats are not necessarily less allergenic than long-haired animals, and furless cats give off similar amounts of allergen as furred cats.
If a person with asthma is found to be allergic to a pet, the pet should be removed from the home. Limiting an animal to a certain area in the house is not effective because some allergens are carried on clothing or spread in the air. Once a pet has left a home, careful cleaning of carpets, sofas, curtain, and bedding must follow. This is particularly true for cat allergens, as they are "sticky" and adhere to a variety of indoor surfaces. Even after a cat has been removed from a home and it has been thoroughly cleaned, it can take months for levels of cat allergen to drop . For this reason, it may take months for the allergic person's symptoms to fully reflect the absence of the pet.
If it is not possible to remove the animal, measures can be taken to decrease exposure to the animal dander (show table 3), although none of these methods is as effective as removing the animal.
Cockroaches — Cockroach droppings contain allergens that have been shown to trigger asthma in sensitive individuals. Cockroaches thrive in warm environments with easily accessible food and water. Unfortunately, efforts to control cockroach populations in infested areas are often less than successful. Still, certain measures should be tried, including: Using multiple baited traps or poisons Removing garbage and food waste promptly from the home Washing dishes and cooking utensils immediately after use Removing cockroach debris quickly Eliminating any standing water from leaking faucets or drains
The role of air filters — Air filtering devices, including HEPA and other mechanical filters as well as electrostatic filters, are widely advertised and can be quite costly. These may be marketed as components of heating or cooling systems, as individual units for use in a room or area, or as units that are worn by individuals. None of these filtration devices have been scientifically proven to have a significant impact on asthma symptoms.
One possible explanation for this is that although these devices may clean the air, allergen levels cannot be effectively reduced unless measures are taken to eliminate their source. Thus, air filtration may be a useful adjunct to the measures described above, although we advise directing financial resources and efforts primarily towards eliminating sources of allergens.
CONTROLLING OTHER ASTHMA TRIGGERS — In addition to indoor allergens, other factors may be identified as asthma triggers.
Respiratory infections — Infections that cause airway inflammation can trigger asthma, including colds, influenza (flu), bronchitis, ear infections, sinus infections, and pneumonia. An asthma attack that occurs along with a respiratory infection may be more severe than one that occurs at other times. (See "Patient information: Influenza" and see "Patient information: Pneumonia in adults" and see "Patient information: The common cold in adults").
To reduce the risk of a serious flare related to respiratory infection, a person with asthma should: Call a healthcare provider at the first sign of an infection. Get a flu shot once a year. Get a pneumonia vaccine (if needed based on other risk factors) Wash hands frequently, especially when in contact with an infected person, and avoid contact with infected people when possible. Use treatments prescribed for symptoms, such as nasal steroids and decongestants.
Allergies to food and medicine — Allergy to foods, especially foods containing sulfites (potatoes, shrimp, dried fruit, beer, wine) may trigger asthma in sensitive individuals. A food diary, listing all food and drink and chronicling asthma symptoms, may help isolate sensitivity to a particular food. If a sulfite allergy has been identified, the patient should be sure to read food labels to make sure sulfites are not present.
Sensitivity to medications can also trigger asthma. In particular, aspirin, some other anti-inflammatory drugs such as ibuprofen (Advil®, Motrin®) and naproxen (Aleve®, Anaprox®) and certain beta blocker heart medicines may cause an attack in certain individuals. Acetaminophen (Tylenol®) does not cause symptoms in most aspirin-sensitive patients.
Outdoor allergens — Asthma symptoms that worsen outdoors at certain times of year are likely to be triggered by an allergy to pollen or other plant material. Affected individuals should stay indoors as much as possible during the season when their asthma tends to flare and keep windows closed. Patients should also try to avoid cutting grass, digging around plants, or other outdoor activities that seem to worsen asthma symptoms.
Irritants — A variety of irritants can trigger asthma. Irritants can be found inside or outside, and include: Cigarette smoke and ashes — A person with asthma should never smoke, smoking should not be allowed in the person's home, and second-hand smoke should be avoided whenever possible. (See "Patient information: Smoking cessation"). Aerosol sprays, perfumes — Non-aerosol products should be used, and exposure to offending perfumes avoided. Fireplace smoke and cooking odors — Wood-burning stoves, fireplaces, and pellet stoves should not be used, and cooking areas should be well ventilated. Air pollution, car exhaust, gas fumes — Patients should avoid unnecessary exposure to car exhaust, and outdoor exercise should be avoided when pollution levels are high.
Chemicals — Industrial or occupational exposure to chemicals is responsible for about 15 percent of cases of asthma. If symptoms tend to flare in a workplace where chemicals are in use, the patient and healthcare provider can discuss strategies to limit exposure.
If possible, patients whose asthma is triggered by strong odors should also avoid the use of chlorine and bleach-based cleaning products. If these cleaners are needed to control the growth of mold in the home, efforts should be made to ventilate the area thoroughly during and after use, and if possible, have a non-asthmatic person perform the cleaning.
Menstrual cycle — Worsening of asthma symptoms before or during menstruation has been reported in 20 to 40 percent of women with asthma. The reason for this phenomenon is unclear. Women with hormonally-triggered asthma tend to have more severe asthma than women whose asthma is unaffected by hormonal levels.
The optimal management of menstrual-associated asthma flares has not been determined, although women with a history of this problem are advised to increase their medication if necessary and avoid other potential asthma triggers.
Physical activity — Although exercise can trigger asthma in certain people, it should not be avoided. Exercise strengthens the cardiovascular system and may decrease sensitivity to asthma triggers. To minimize the effects of this trigger, asthmatics should: Take one or 2 puffs from an albuterol inhaler 5 minutes before beginning exercise Start any new exercise regime slowly, gradually building strength and endurance. Warm up gradually at the beginning of each exercise session. Take all medications on schedule. Avoid exercising outdoors in extremely cold weather and cover the mouth and nose with a scarf to help warm the inspired air when temperatures are low.
SUMMARY Asthma is a chronic lung condition that causes inflammation and constriction of the airways and difficulty breathing. Asthma attacks, or worsening of asthma symptoms, can occur after exposure to factors known as triggers (show table 1). Once asthma triggers have been identified, the patient has several options: avoid the trigger entirely, limit exposure to the trigger if it cannot be completely avoided, consult with a healthcare provider about taking an extra dose of medicine before exposure to the trigger, or consider immunotherapy (allergy shots), which can sometimes be helpful. Allergens are substances that can produce an allergic reaction in people who are sensitive (allergic) to them. Sensitivity to indoor allergens is especially common in asthmatics. The most common indoor allergens that affect asthmatics are dust mites, mold, animal danders, and cockroaches. In addition to indoor allergens, other factors may be identified as asthma triggers, including respiratory infections (colds, flu), allergies to food or medicines, outdoor allergens (pollen, grasses), irritants (cigarette smoke, aerosols, wood smoke, car exhaust), chemicals in the home or workplace, a woman's menses, or physical activity.
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. The National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
American Academy of Allergy, Asthma, and Immunology
(www.aaaai.org)
National Heart, Lung, and Blood Institute
(www.nhlbi.nih.gov/)
National Lung Health Education Program
(www.nlhep.org)
American Lung Association
(www.lungusa.org)
American College of Allergy, Asthma, and Immunology
(allergy.mcg.edu/)
[1-5]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. National Asthma Education and Prevention Program. Expert Panel Report: Guidelines for the Diagnosis and Management of Asthma Update on Selected Topics--2002. J Allergy Clin Immunol 2002; 110:S141.
2. Platts-Mills, TA, Vervloet, D, Thomas, WR, et al. Indoor allergens and asthma: report of the Third International Workshop. J Allergy Clin Immunol 1997; 100:S2.
3. Sporik, RB, Holgate, ST, Platts-Mills, TAE, Cogswell, J. Exposure to house dust mite allergen (Der p I) and the development of asthma in childhood: A prospective study. N Engl J Med 1990; 323:502.
4. Wood, RA, Johnson, EF, Van Natta, ML, et al. A placebo-controlled trial of a HEPA air cleaner in the treatment of cat allergy. Am J Respir Crit Care Med 1998; 158:115.
5. Cates, CJ, Jefferson, TO, Bara, AI, Rowe, BH. Vaccines for preventing influenza in people with asthma. Cochrane Database Syst Rev 2004; :CD000364.
ASTHMA Patient information: Pregnancy and asthma
INTRODUCTION — Asthma is the most common condition affecting the lungs during pregnancy. At any given time, up to 8 percent of pregnant women have asthma.
It is normal to worry about how the changes of pregnancy will affect asthma and if asthma and its treatments will harm the baby. With good asthma therapy, most women can breathe easily, have a normal pregnancy, and deliver a healthy baby. Overall, the risk of poorly controlled asthma is much higher than the risk of taking medications to control asthma.
Asthma therapy during pregnancy is most successful when a woman receives regular medical care and follows her treatment plan closely. Before becoming pregnant, women with asthma should learn as much as they can about their condition and talk with their healthcare providers about asthma therapy during pregnancy.
SEVERITY OF SYMPTOMS — The effects of pregnancy on asthma vary from woman to woman. Unfortunately, it is difficult to predict the course that asthma will follow in individual women who become pregnant for the first time. During pregnancy, asthma worsens in one-third of women, improves in one-third, and remains stable in one-third.
Other patterns that have been observed include: Among women whose asthma worsens, worsening is most rapid between weeks 29 and 36 of pregnancy. Asthma is generally less severe during the last month of pregnancy. Labor and delivery are not usually associated with a worsening of asthma. Among women whose asthma improves, the improvement progresses gradually throughout pregnancy. The severity of asthma symptoms in a first pregnancy is often similar in subsequent pregnancies.
Factors affecting risk of attacks — The factors that increase or decrease the risk of asthma attacks during pregnancy are not entirely clear. The likelihood of these attacks is not constant throughout pregnancy; attacks seem to be most likely during weeks 17 through 24 of pregnancy (show figure 1). The cause for this pattern is unknown, but researchers suspect that women may stop using asthma-controlling drugs when they discover that they are pregnant, increasing their risk for attacks.
EFFECTS OF ASTHMA ON PREGNANCY AND BABY — Women who have asthma have a small increase in the risk for certain complications of pregnancy, although the reasons for this are unknown. Compared to women who do not have asthma, women with asthma are slightly more likely to develop high blood pressure and preeclampsia during pregnancy, to have a placental abnormality called placenta previa, to have a premature delivery, and to require a cesarean delivery. Women with asthma are also slightly more likely to have a baby that is small for its age.
However, the vast majority of women with asthma and their babies do NOT have any complications during pregnancy. Good control of asthma during pregnancy reduces the risk of complications.
ASTHMA THERAPY DURING PREGNANCY — Good asthma therapy is essential to ensuring the health of both the mother and the baby. Asthma therapy in pregnant women is very similar to asthma therapy in nonpregnant women. Therapy during pregnancy has several key components, which are most successful when used together:
Monitoring Mother's lung function — Normal lung function is important to a mother's health and to her baby's well-being. Lung function can be monitored in a healthcare provider's office or hospital, although home monitoring often provides important information when asthma symptoms worsen, typically during the night or upon awakening.
Pregnant women can monitor their lung function at home by using a simple device that measures the peak expiratory flow rate (PEFR). Depending on the frequency of attacks, a healthcare provider may recommend measuring this rate twice per day: once upon awakening and again 12 hours later. Decreasing flow rates usually signal a worsening of asthma and a need for more intensive therapy, even if the patient is feeling well. (See "Patient information: How to use a peak flow meter").
Lung function tests performed in the doctor's office are also useful for distinguishing the shortness of breath associated with a worsening of asthma from the normal shortness of breath that many women experience during pregnancy. Baby's well-being — A baby's well-being is carefully monitored during regular medical visits throughout pregnancy. These visits are particularly important for women who have asthma.
Avoiding triggers — Several simple steps can help control environmental factors that worsen asthma and trigger attacks. These include: Avoid exposure to specific allergens, especially pet dander (such as fur or feathers), house dust, and nonspecific irritants, such as tobacco smoke, dust, and pollutants Cover mattresses and pillows with special casings to avoid house dust mites. Avoid sleeping on upholstered furniture (eg, couches, recliners). Pregnant women should not smoke or permit smoking in their home.
(For more information about trigger avoidance, see "Patient information: Trigger avoidance in asthma").
Education — Learning about asthma enables people with this condition to better manage their symptoms, prevent attacks, and react when attacks do occur. This education can be particularly reassuring and useful during pregnancy. Asthma education usually teaches strategies for recognizing the signs and symptoms of asthma, avoiding factors that trigger attacks, correctly using asthma-controlling drugs, and developing an individualized treatment plan for acute attacks.
Drug therapy — With a few exceptions, the drug therapy for asthma during pregnancy is very similar to the drug therapy for asthma at other times during a person's life.
Safety of allergy-controlling drugs — It is difficult to prove that asthma-controlling drugs are completely safe during pregnancy, but evidence from the use of these drugs in pregnant women for many years suggests that most of them probably carry little or no risk for the mother or baby.
It is important to weigh the unknown (but likely small) risks of asthma-controlling drugs against the potentially serious harm of undertreated asthma. In most cases, undertreated asthma poses a far greater risk to both the mother and the baby than the use of asthma-controlling drugs.
Types of asthma drugs — There are many different types of asthma-controlling drugs, and the drug or drugs that your healthcare provider recommends will depend upon many factors. In general, inhaled drugs are usually recommended because there is limited body-wide effects in the mother and the baby. It may be necessary to adjust the type or dose of drugs during pregnancy to compensate for changes in metabolism and the severity of asthma. Bronchodilators — Bronchodilators rapidly relieve asthma symptoms by relaxing the airways. They include albuterol (Proventil®, Ventolin®), metaproterenol (Alupent®), terbutaline, and other drugs. Newer drugs, such as salmeterol (Serevent®) and formoterol (Foradil®), are longer-acting bronchodilators; these have been used less frequently during pregnancy, so assessment of potential risk to the unborn baby is more difficult.
Bronchodilators appear to be safe during pregnancy. One study showed that the babies of women who used these drugs during pregnancy had no increase in health problems when compared to the babies of mothers who did not. About 70 percent of these women used the bronchodilators during the first trimester of pregnancy (a particularly sensitive time in fetal development), further suggesting that these drugs are safe.
A healthcare provider may avoid giving bronchodilator pills near the time of delivery because they can weaken uterine contractions. Corticosteroids — Corticosteroids are used to treat many conditions in addition to asthma. Experience from their use in pregnant women suggests that these drugs are generally safe for both the mother and the baby. The corticosteroids include pills such as prednisone and inhaled drugs such as beclomethasone (Beclovent®, Vanceril®, and others), triamcinolone (Azmacort®), flunisolide (AeroBid®), budesonide (Pulmicort®), and fluticasone (Flovent®).
- Oral corticosteroids - Some studies have suggested that there may be an increased risk of cleft lip or cleft palate in the babies of mothers who took oral steroid medications during the first trimester of pregnancy, although these results are not definitive. Two studies found a slightly increased risk of premature delivery, and one study found a slightly increased risk of having a low birth weight baby. However, the researchers could not rule out the possibility that these effects were related to the severity of asthma and not to the use of the drug. In very rare cases, a mother's use of corticosteroids may cause adrenal insufficiency (poor function of the adrenal glands) in the baby at the time of birth, but this condition can be treated and resolves over time.
Women who use corticosteroid pills during pregnancy may be more likely to develop gestational diabetes and high blood pressure, but these conditions can be detected and managed with regular medical visits.
Any of the above risks are probably smaller than the risk of not treating severe asthma, which could be life-threatening for the mother and the baby.
- Inhaled corticosteroids - The information about inhaled corticosteroids is quite reassuring. A variety of inhaled corticosteroids have been used during pregnancy. Budesonide is thought to be one of the safest inhaled corticosteroids. Beclomethasone has also been used extensively during pregnancy. Theophylline — Theophylline (Slo-bid®, Theo-Dur®, and others) has been used for many years during pregnancy without any apparent complications, suggesting that it is safe during pregnancy. As examples, one study of 193 women who took theophylline during pregnancy found no increase in complications; another study found that the risk of stillbirth was no greater in women who took these drugs than in women who did not.
The physiologic changes of pregnancy alter the body's metabolism of theophylline, frequently requiring an adjustment of the dosage. Theophylline, like the beta agonist bronchodilators, can block uterine contractions when taken near delivery. It may also cause a rapid heart beat and fussiness in the baby at the time of delivery, but these effects are usually short-lived. Theophylline can worsen symptoms of heartburn and nausea in the mother; another medicine may be preferred if these symptoms occur.
Since the introduction of the inhaled corticosteroids, theophylline is used less often for asthma in general, including during pregnancy. Inhaled corticosteroids have been shown to be more effective and to cause fewer side effects than theophylline. Cromolyn sodium — There was no increase in birth defects or other pregnancy complications in one study of women who took cromolyn sodium during pregnancy. Although it appears to be a very safe drug, it is not as effective in controlling asthma as inhaled corticosteroids Drugs that affect the leukotriene pathway — Some drugs help control asthma by blocking the leukotriene pathway, which plays an important role in asthma. These drugs include zafirlukast (Accolate®), montelukast (Singulair®), and zileuton (Zyflo™). Studies in animals suggest that zafirlukast and montelukast do not cause birth defects when taken during pregnancy, but there are no studies on the safety of these drugs during pregnancy. Little is known about the safety of zileuton in pregnant women, but it does increase the risk of pregnancy complications in animals and is not generally recommended for use during pregnancy. Antihistamines — Although antihistamines are not used to directly treat asthma, they may be used to treat the allergies that often accompany asthma. These drugs include chlorpheniramine (Chlor-Trimeton® and others), loratadine (Claritin®), fexofenadine (Allegra®), and cetirizine (Zyrtec®). Studies in both animals and humans suggest that antihistamines cause no increase or only a very small increase in the risk for birth defects when taken during pregnancy. Of the currently available preparations, chlorpheniramine (which can be sedating), loratadine, or cetirizine are considered the antihistamines of choice for use during pregnancy. Decongestants — Decongestants are not used for the treatment of asthma, but they may be used to treat the symptoms of upper airway allergies. Pseudoephedrine (Sudafed®) is a decongestant that is commonly available. Most studies examining the safety of decongestants during pregnancy have been small, making it difficult to draw clear-cut conclusions. Until more information is available, it would probably be best to avoid the use of any oral decongestants during the first trimester of pregnancy. After the first trimester, the use of pseudoephedrine is thought to be safe in women without high blood pressure. Immunotherapy — Immunotherapy refers to regular injections (allergy shots) given to reduce a person's sensitivity to allergens. This therapy appears to be safe during pregnancy, although it carries a very small risk of a severe allergic reaction (anaphylaxis) in any patient, including pregnant women.
It is probably safe for women who are already receiving immunotherapy to continue receiving shots during pregnancy. Women who are not receiving immunotherapy at the time they become pregnant generally should not start immunotherapy until after delivery.
Labor, delivery, and the postpartum period — Pregnant women with asthma should discuss their labor and delivery plans with their healthcare provider. Asthma will affect a provider's choice of medications commonly used during labor, delivery, and the postpartum period.
Women with asthma can be treated with the drug oxytocin (Pitocin®) to induce labor and to control bleeding after delivery. During labor and delivery, epidural anesthesia is preferred over general anesthesia for women with asthma because epidural anesthesia reduces the demands on the lungs. If general anesthesia becomes necessary, doctors select specific general anesthetics that promote dilation of airways. The painkillers morphine and meperidine (Demerol®) are usually not recommended for women with asthma because these drugs can cause a release of histamine and worsen an asthma attack, but the painkillers butorphanol (Stadol®) or fentanyl (Sublimaze®) are safe and effective alternatives.
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
American Lung Association
(www.lungusa.org)
Canadian Lung Association
(www.lung.ca)
American Academy of Allergy, Asthma, and Immunology
(www.aaaai.org/patients.stm)
National Heart, Lung, and Blood Institute
(www.nhlbi.nih.gov/health/prof/lung/asthma/astpreg.htm)
[1-5]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Demissie, K, Breckenridge, MB, Rhoads, CG. Infant and maternal outcomes in the pregnancies of asthmatic women. Am J Respir Crit Care Med 1998; 158:1095.
2. Minerbi-Codish, I, Fraser, D, Avnun, L, et al. Influence of asthma in pregnancy on labor and the newborn. Respiration 1998; 65:130.
3. National Asthma Education Program: Report of the Working Group on Asthma and Pregnancy. Management of asthma during pregnancy. National Institutes of Health (NIH publication no. 933279A), Bethesda, MD, 1993. (www.nhlbi.nih.gov/health/prof/lung/asthma/astpreg.txt).
4. Schatz, M. Asthma and pregnancy. Lancet 1999; 353:1202.
5. Wendel, PJ, Ramin, SM, Barnett-Hamm, C, et al. Asthma treatment in pregnancy. A randomized controlled study. Am J Obstet Gynecol 1996; 175:150.
It is normal to worry about how the changes of pregnancy will affect asthma and if asthma and its treatments will harm the baby. With good asthma therapy, most women can breathe easily, have a normal pregnancy, and deliver a healthy baby. Overall, the risk of poorly controlled asthma is much higher than the risk of taking medications to control asthma.
Asthma therapy during pregnancy is most successful when a woman receives regular medical care and follows her treatment plan closely. Before becoming pregnant, women with asthma should learn as much as they can about their condition and talk with their healthcare providers about asthma therapy during pregnancy.
SEVERITY OF SYMPTOMS — The effects of pregnancy on asthma vary from woman to woman. Unfortunately, it is difficult to predict the course that asthma will follow in individual women who become pregnant for the first time. During pregnancy, asthma worsens in one-third of women, improves in one-third, and remains stable in one-third.
Other patterns that have been observed include: Among women whose asthma worsens, worsening is most rapid between weeks 29 and 36 of pregnancy. Asthma is generally less severe during the last month of pregnancy. Labor and delivery are not usually associated with a worsening of asthma. Among women whose asthma improves, the improvement progresses gradually throughout pregnancy. The severity of asthma symptoms in a first pregnancy is often similar in subsequent pregnancies.
Factors affecting risk of attacks — The factors that increase or decrease the risk of asthma attacks during pregnancy are not entirely clear. The likelihood of these attacks is not constant throughout pregnancy; attacks seem to be most likely during weeks 17 through 24 of pregnancy (show figure 1). The cause for this pattern is unknown, but researchers suspect that women may stop using asthma-controlling drugs when they discover that they are pregnant, increasing their risk for attacks.
EFFECTS OF ASTHMA ON PREGNANCY AND BABY — Women who have asthma have a small increase in the risk for certain complications of pregnancy, although the reasons for this are unknown. Compared to women who do not have asthma, women with asthma are slightly more likely to develop high blood pressure and preeclampsia during pregnancy, to have a placental abnormality called placenta previa, to have a premature delivery, and to require a cesarean delivery. Women with asthma are also slightly more likely to have a baby that is small for its age.
However, the vast majority of women with asthma and their babies do NOT have any complications during pregnancy. Good control of asthma during pregnancy reduces the risk of complications.
ASTHMA THERAPY DURING PREGNANCY — Good asthma therapy is essential to ensuring the health of both the mother and the baby. Asthma therapy in pregnant women is very similar to asthma therapy in nonpregnant women. Therapy during pregnancy has several key components, which are most successful when used together:
Monitoring Mother's lung function — Normal lung function is important to a mother's health and to her baby's well-being. Lung function can be monitored in a healthcare provider's office or hospital, although home monitoring often provides important information when asthma symptoms worsen, typically during the night or upon awakening.
Pregnant women can monitor their lung function at home by using a simple device that measures the peak expiratory flow rate (PEFR). Depending on the frequency of attacks, a healthcare provider may recommend measuring this rate twice per day: once upon awakening and again 12 hours later. Decreasing flow rates usually signal a worsening of asthma and a need for more intensive therapy, even if the patient is feeling well. (See "Patient information: How to use a peak flow meter").
Lung function tests performed in the doctor's office are also useful for distinguishing the shortness of breath associated with a worsening of asthma from the normal shortness of breath that many women experience during pregnancy. Baby's well-being — A baby's well-being is carefully monitored during regular medical visits throughout pregnancy. These visits are particularly important for women who have asthma.
Avoiding triggers — Several simple steps can help control environmental factors that worsen asthma and trigger attacks. These include: Avoid exposure to specific allergens, especially pet dander (such as fur or feathers), house dust, and nonspecific irritants, such as tobacco smoke, dust, and pollutants Cover mattresses and pillows with special casings to avoid house dust mites. Avoid sleeping on upholstered furniture (eg, couches, recliners). Pregnant women should not smoke or permit smoking in their home.
(For more information about trigger avoidance, see "Patient information: Trigger avoidance in asthma").
Education — Learning about asthma enables people with this condition to better manage their symptoms, prevent attacks, and react when attacks do occur. This education can be particularly reassuring and useful during pregnancy. Asthma education usually teaches strategies for recognizing the signs and symptoms of asthma, avoiding factors that trigger attacks, correctly using asthma-controlling drugs, and developing an individualized treatment plan for acute attacks.
Drug therapy — With a few exceptions, the drug therapy for asthma during pregnancy is very similar to the drug therapy for asthma at other times during a person's life.
Safety of allergy-controlling drugs — It is difficult to prove that asthma-controlling drugs are completely safe during pregnancy, but evidence from the use of these drugs in pregnant women for many years suggests that most of them probably carry little or no risk for the mother or baby.
It is important to weigh the unknown (but likely small) risks of asthma-controlling drugs against the potentially serious harm of undertreated asthma. In most cases, undertreated asthma poses a far greater risk to both the mother and the baby than the use of asthma-controlling drugs.
Types of asthma drugs — There are many different types of asthma-controlling drugs, and the drug or drugs that your healthcare provider recommends will depend upon many factors. In general, inhaled drugs are usually recommended because there is limited body-wide effects in the mother and the baby. It may be necessary to adjust the type or dose of drugs during pregnancy to compensate for changes in metabolism and the severity of asthma. Bronchodilators — Bronchodilators rapidly relieve asthma symptoms by relaxing the airways. They include albuterol (Proventil®, Ventolin®), metaproterenol (Alupent®), terbutaline, and other drugs. Newer drugs, such as salmeterol (Serevent®) and formoterol (Foradil®), are longer-acting bronchodilators; these have been used less frequently during pregnancy, so assessment of potential risk to the unborn baby is more difficult.
Bronchodilators appear to be safe during pregnancy. One study showed that the babies of women who used these drugs during pregnancy had no increase in health problems when compared to the babies of mothers who did not. About 70 percent of these women used the bronchodilators during the first trimester of pregnancy (a particularly sensitive time in fetal development), further suggesting that these drugs are safe.
A healthcare provider may avoid giving bronchodilator pills near the time of delivery because they can weaken uterine contractions. Corticosteroids — Corticosteroids are used to treat many conditions in addition to asthma. Experience from their use in pregnant women suggests that these drugs are generally safe for both the mother and the baby. The corticosteroids include pills such as prednisone and inhaled drugs such as beclomethasone (Beclovent®, Vanceril®, and others), triamcinolone (Azmacort®), flunisolide (AeroBid®), budesonide (Pulmicort®), and fluticasone (Flovent®).
- Oral corticosteroids - Some studies have suggested that there may be an increased risk of cleft lip or cleft palate in the babies of mothers who took oral steroid medications during the first trimester of pregnancy, although these results are not definitive. Two studies found a slightly increased risk of premature delivery, and one study found a slightly increased risk of having a low birth weight baby. However, the researchers could not rule out the possibility that these effects were related to the severity of asthma and not to the use of the drug. In very rare cases, a mother's use of corticosteroids may cause adrenal insufficiency (poor function of the adrenal glands) in the baby at the time of birth, but this condition can be treated and resolves over time.
Women who use corticosteroid pills during pregnancy may be more likely to develop gestational diabetes and high blood pressure, but these conditions can be detected and managed with regular medical visits.
Any of the above risks are probably smaller than the risk of not treating severe asthma, which could be life-threatening for the mother and the baby.
- Inhaled corticosteroids - The information about inhaled corticosteroids is quite reassuring. A variety of inhaled corticosteroids have been used during pregnancy. Budesonide is thought to be one of the safest inhaled corticosteroids. Beclomethasone has also been used extensively during pregnancy. Theophylline — Theophylline (Slo-bid®, Theo-Dur®, and others) has been used for many years during pregnancy without any apparent complications, suggesting that it is safe during pregnancy. As examples, one study of 193 women who took theophylline during pregnancy found no increase in complications; another study found that the risk of stillbirth was no greater in women who took these drugs than in women who did not.
The physiologic changes of pregnancy alter the body's metabolism of theophylline, frequently requiring an adjustment of the dosage. Theophylline, like the beta agonist bronchodilators, can block uterine contractions when taken near delivery. It may also cause a rapid heart beat and fussiness in the baby at the time of delivery, but these effects are usually short-lived. Theophylline can worsen symptoms of heartburn and nausea in the mother; another medicine may be preferred if these symptoms occur.
Since the introduction of the inhaled corticosteroids, theophylline is used less often for asthma in general, including during pregnancy. Inhaled corticosteroids have been shown to be more effective and to cause fewer side effects than theophylline. Cromolyn sodium — There was no increase in birth defects or other pregnancy complications in one study of women who took cromolyn sodium during pregnancy. Although it appears to be a very safe drug, it is not as effective in controlling asthma as inhaled corticosteroids Drugs that affect the leukotriene pathway — Some drugs help control asthma by blocking the leukotriene pathway, which plays an important role in asthma. These drugs include zafirlukast (Accolate®), montelukast (Singulair®), and zileuton (Zyflo™). Studies in animals suggest that zafirlukast and montelukast do not cause birth defects when taken during pregnancy, but there are no studies on the safety of these drugs during pregnancy. Little is known about the safety of zileuton in pregnant women, but it does increase the risk of pregnancy complications in animals and is not generally recommended for use during pregnancy. Antihistamines — Although antihistamines are not used to directly treat asthma, they may be used to treat the allergies that often accompany asthma. These drugs include chlorpheniramine (Chlor-Trimeton® and others), loratadine (Claritin®), fexofenadine (Allegra®), and cetirizine (Zyrtec®). Studies in both animals and humans suggest that antihistamines cause no increase or only a very small increase in the risk for birth defects when taken during pregnancy. Of the currently available preparations, chlorpheniramine (which can be sedating), loratadine, or cetirizine are considered the antihistamines of choice for use during pregnancy. Decongestants — Decongestants are not used for the treatment of asthma, but they may be used to treat the symptoms of upper airway allergies. Pseudoephedrine (Sudafed®) is a decongestant that is commonly available. Most studies examining the safety of decongestants during pregnancy have been small, making it difficult to draw clear-cut conclusions. Until more information is available, it would probably be best to avoid the use of any oral decongestants during the first trimester of pregnancy. After the first trimester, the use of pseudoephedrine is thought to be safe in women without high blood pressure. Immunotherapy — Immunotherapy refers to regular injections (allergy shots) given to reduce a person's sensitivity to allergens. This therapy appears to be safe during pregnancy, although it carries a very small risk of a severe allergic reaction (anaphylaxis) in any patient, including pregnant women.
It is probably safe for women who are already receiving immunotherapy to continue receiving shots during pregnancy. Women who are not receiving immunotherapy at the time they become pregnant generally should not start immunotherapy until after delivery.
Labor, delivery, and the postpartum period — Pregnant women with asthma should discuss their labor and delivery plans with their healthcare provider. Asthma will affect a provider's choice of medications commonly used during labor, delivery, and the postpartum period.
Women with asthma can be treated with the drug oxytocin (Pitocin®) to induce labor and to control bleeding after delivery. During labor and delivery, epidural anesthesia is preferred over general anesthesia for women with asthma because epidural anesthesia reduces the demands on the lungs. If general anesthesia becomes necessary, doctors select specific general anesthetics that promote dilation of airways. The painkillers morphine and meperidine (Demerol®) are usually not recommended for women with asthma because these drugs can cause a release of histamine and worsen an asthma attack, but the painkillers butorphanol (Stadol®) or fentanyl (Sublimaze®) are safe and effective alternatives.
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
American Lung Association
(www.lungusa.org)
Canadian Lung Association
(www.lung.ca)
American Academy of Allergy, Asthma, and Immunology
(www.aaaai.org/patients.stm)
National Heart, Lung, and Blood Institute
(www.nhlbi.nih.gov/health/prof/lung/asthma/astpreg.htm)
[1-5]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Demissie, K, Breckenridge, MB, Rhoads, CG. Infant and maternal outcomes in the pregnancies of asthmatic women. Am J Respir Crit Care Med 1998; 158:1095.
2. Minerbi-Codish, I, Fraser, D, Avnun, L, et al. Influence of asthma in pregnancy on labor and the newborn. Respiration 1998; 65:130.
3. National Asthma Education Program: Report of the Working Group on Asthma and Pregnancy. Management of asthma during pregnancy. National Institutes of Health (NIH publication no. 933279A), Bethesda, MD, 1993. (www.nhlbi.nih.gov/health/prof/lung/asthma/astpreg.txt).
4. Schatz, M. Asthma and pregnancy. Lancet 1999; 353:1202.
5. Wendel, PJ, Ramin, SM, Barnett-Hamm, C, et al. Asthma treatment in pregnancy. A randomized controlled study. Am J Obstet Gynecol 1996; 175:150.
ASTHMA Patient information: Trigger avoidance in asthma
INTRODUCTION — Asthma is a chronic lung condition that causes inflammation and constriction of the airways and difficulty breathing. Asthma attacks, or worsening of asthma symptoms, can occur after exposure to factors known as triggers (show table 1).
Not all patients with asthma have the same triggers. Finding out which factors trigger an attack and taking steps to avoid the triggers are important parts of good asthma management.
IDENTIFYING AND MANAGING TRIGGERS — Careful attention to the pattern of asthma symptoms is an important part of identifying triggers. For example, if symptoms occur primarily at home, something in that environment may be involved. If symptoms flare in the spring or fall, an outdoor allergy is more likely to blame.
Additional information about possible asthma triggers can sometimes be gained by using blood tests or skin tests to see if a patient is sensitive (or allergic) to a particular substance.
Once asthma triggers have been identified, the patient has several options: Avoid the trigger entirely. Limit exposure to the trigger if it cannot be completely avoided. If a trigger is encountered in a predictable manner, consult with a healthcare provider about taking an extra dose of medicine before exposure to the trigger. Immunotherapy (allergy shots) can sometimes be helpful.
INDOOR TRIGGERS — Allergens are substances that can produce an allergic reaction and are major triggers in many people with asthma. Sensitivity to indoor allergens is especially common in asthmatics. The most common indoor allergens that affect asthmatics are dust mites, mold, animal danders, and cockroaches. The bedroom of the asthmatic person should be given special consideration because the greatest number of hours are typically spent there. However, to be effective, measures must be made to reduce allergens throughout the entire home.
Dust mites — Dust mites are microscopic organisms that are present in most households. They avoid light and absorb humidity from the atmosphere (ie, they do not drink). Mites may live in bedding, sofas, carpets, or any woven material if the humidity is high enough.
Measures that help limit exposure to dust mites are detailed in Table 2 and include (show table 2) : Create a physical barrier to the source of the mites by covering pillows and mattresses with plastic or another impermeable fabric covers. A potential source of confusion when purchasing bedding covers is the availability of "hypoallergenic" unbleached or organic cotton bedding covers. These do not limit the passage of dust mites and are intended for people who have contact sensitivities to fabric dyes. Decrease the population of dust mites in the home by washing bedding in hot water and removing carpets and stuffed toys; these measures help to reduce nesting areas for mites. Control humidity. Mites thrive in humid environments. Opening windows in dry climates and using air conditioning in humid ones decreases humidity in the home and reduces the number of mites. Moving to or spending more time on upper floors of buildings may help, as upper floors tend to be less humid than lower floors or basements. Household humidity should be below 50 percent if possible. Inexpensive humidity monitors can be purchased at most hardware stores.
Mold — Mold spores can trigger asthma in allergic patients. Mold thrives in damp environments. Area such as air conditioning vents, water traps, refrigerator drip trays, shower stalls, leaky sinks, and damp basements are particularly vulnerable to mold growth if not cleaned regularly.
General measures to reduce mold exposure include the quick repair of any plumbing leaks, removal of bathroom carpeting which is exposed to steam and moisture, and scouring of sinks and tubs at least every four weeks with dilute bleach (1 ounce diluted in one quart of water); mold thrives on soap film that covers tiles and grout. In addition, indoor garbage pails should be regularly disinfected, and an electric dehumidifier should be used to remove moisture from the basement. Old books, newspapers, clothing, and bedding should not be stored in the home. Water damaged carpets should be thrown out because eliminating mold is difficult or impossible, even with thorough cleaning. For an important note about the use of bleach by people with asthma, see below (see "Irritants" below).
Animal danders — Asthma can be triggered by proteins from the "dander," saliva, and urine of common house pets such as cats and dogs. Other warm-blooded animals, such as rodents, birds, and ferrets can also trigger asthma in an allergic individual. Pets without feathers or fur, such as reptiles, turtles, and fish, rarely cause allergy, although deposits of fish food that may build up under the covers of fish tanks are an excellent source of food for dust mite colonies.
Animal dander is made up of the dead skin cells or scales (like dandruff) that are constantly shed by animals. Any breed of dog and cat is capable of being allergenic, although the levels given off by individual animals may vary to some degree. In cats, the protein that causes most people's allergies is found in the cat's saliva, skin glands, and urinary/reproductive tract. Accordingly, short-haired cats are not necessarily less allergenic than long-haired animals, and furless cats give off similar amounts of allergen as furred cats.
If a person with asthma is found to be allergic to a pet, the pet should be removed from the home. Limiting an animal to a certain area in the house is not effective because some allergens are carried on clothing or spread in the air. Once a pet has left a home, careful cleaning of carpets, sofas, curtain, and bedding must follow. This is particularly true for cat allergens, as they are "sticky" and adhere to a variety of indoor surfaces. Even after a cat has been removed from a home and it has been thoroughly cleaned, it can take months for levels of cat allergen to drop . For this reason, it may take months for the allergic person's symptoms to fully reflect the absence of the pet.
If it is not possible to remove the animal, measures can be taken to decrease exposure to the animal dander (show table 3), although none of these methods is as effective as removing the animal.
Cockroaches — Cockroach droppings contain allergens that have been shown to trigger asthma in sensitive individuals. Cockroaches thrive in warm environments with easily accessible food and water. Unfortunately, efforts to control cockroach populations in infested areas are often less than successful. Still, certain measures should be tried, including: Using multiple baited traps or poisons Removing garbage and food waste promptly from the home Washing dishes and cooking utensils immediately after use Removing cockroach debris quickly Eliminating any standing water from leaking faucets or drains
The role of air filters — Air filtering devices, including HEPA and other mechanical filters as well as electrostatic filters, are widely advertised and can be quite costly. These may be marketed as components of heating or cooling systems, as individual units for use in a room or area, or as units that are worn by individuals. None of these filtration devices have been scientifically proven to have a significant impact on asthma symptoms.
One possible explanation for this is that although these devices may clean the air, allergen levels cannot be effectively reduced unless measures are taken to eliminate their source. Thus, air filtration may be a useful adjunct to the measures described above, although we advise directing financial resources and efforts primarily towards eliminating sources of allergens.
CONTROLLING OTHER ASTHMA TRIGGERS — In addition to indoor allergens, other factors may be identified as asthma triggers.
Respiratory infections — Infections that cause airway inflammation can trigger asthma, including colds, influenza (flu), bronchitis, ear infections, sinus infections, and pneumonia. An asthma attack that occurs along with a respiratory infection may be more severe than one that occurs at other times. (See "Patient information: Influenza" and see "Patient information: Pneumonia in adults" and see "Patient information: The common cold in adults").
To reduce the risk of a serious flare related to respiratory infection, a person with asthma should: Call a healthcare provider at the first sign of an infection. Get a flu shot once a year. Get a pneumonia vaccine (if needed based on other risk factors) Wash hands frequently, especially when in contact with an infected person, and avoid contact with infected people when possible. Use treatments prescribed for symptoms, such as nasal steroids and decongestants.
Allergies to food and medicine — Allergy to foods, especially foods containing sulfites (potatoes, shrimp, dried fruit, beer, wine) may trigger asthma in sensitive individuals. A food diary, listing all food and drink and chronicling asthma symptoms, may help isolate sensitivity to a particular food. If a sulfite allergy has been identified, the patient should be sure to read food labels to make sure sulfites are not present.
Sensitivity to medications can also trigger asthma. In particular, aspirin, some other anti-inflammatory drugs such as ibuprofen (Advil®, Motrin®) and naproxen (Aleve®, Anaprox®) and certain beta blocker heart medicines may cause an attack in certain individuals. Acetaminophen (Tylenol®) does not cause symptoms in most aspirin-sensitive patients.
Outdoor allergens — Asthma symptoms that worsen outdoors at certain times of year are likely to be triggered by an allergy to pollen or other plant material. Affected individuals should stay indoors as much as possible during the season when their asthma tends to flare and keep windows closed. Patients should also try to avoid cutting grass, digging around plants, or other outdoor activities that seem to worsen asthma symptoms.
Irritants — A variety of irritants can trigger asthma. Irritants can be found inside or outside, and include: Cigarette smoke and ashes — A person with asthma should never smoke, smoking should not be allowed in the person's home, and second-hand smoke should be avoided whenever possible. (See "Patient information: Smoking cessation"). Aerosol sprays, perfumes — Non-aerosol products should be used, and exposure to offending perfumes avoided. Fireplace smoke and cooking odors — Wood-burning stoves, fireplaces, and pellet stoves should not be used, and cooking areas should be well ventilated. Air pollution, car exhaust, gas fumes — Patients should avoid unnecessary exposure to car exhaust, and outdoor exercise should be avoided when pollution levels are high.
Chemicals — Industrial or occupational exposure to chemicals is responsible for about 15 percent of cases of asthma. If symptoms tend to flare in a workplace where chemicals are in use, the patient and healthcare provider can discuss strategies to limit exposure.
If possible, patients whose asthma is triggered by strong odors should also avoid the use of chlorine and bleach-based cleaning products. If these cleaners are needed to control the growth of mold in the home, efforts should be made to ventilate the area thoroughly during and after use, and if possible, have a non-asthmatic person perform the cleaning.
Menstrual cycle — Worsening of asthma symptoms before or during menstruation has been reported in 20 to 40 percent of women with asthma. The reason for this phenomenon is unclear. Women with hormonally-triggered asthma tend to have more severe asthma than women whose asthma is unaffected by hormonal levels.
The optimal management of menstrual-associated asthma flares has not been determined, although women with a history of this problem are advised to increase their medication if necessary and avoid other potential asthma triggers.
Physical activity — Although exercise can trigger asthma in certain people, it should not be avoided. Exercise strengthens the cardiovascular system and may decrease sensitivity to asthma triggers. To minimize the effects of this trigger, asthmatics should: Take one or 2 puffs from an albuterol inhaler 5 minutes before beginning exercise Start any new exercise regime slowly, gradually building strength and endurance. Warm up gradually at the beginning of each exercise session. Take all medications on schedule. Avoid exercising outdoors in extremely cold weather and cover the mouth and nose with a scarf to help warm the inspired air when temperatures are low.
SUMMARY Asthma is a chronic lung condition that causes inflammation and constriction of the airways and difficulty breathing. Asthma attacks, or worsening of asthma symptoms, can occur after exposure to factors known as triggers (show table 1). Once asthma triggers have been identified, the patient has several options: avoid the trigger entirely, limit exposure to the trigger if it cannot be completely avoided, consult with a healthcare provider about taking an extra dose of medicine before exposure to the trigger, or consider immunotherapy (allergy shots), which can sometimes be helpful. Allergens are substances that can produce an allergic reaction in people who are sensitive (allergic) to them. Sensitivity to indoor allergens is especially common in asthmatics. The most common indoor allergens that affect asthmatics are dust mites, mold, animal danders, and cockroaches. In addition to indoor allergens, other factors may be identified as asthma triggers, including respiratory infections (colds, flu), allergies to food or medicines, outdoor allergens (pollen, grasses), irritants (cigarette smoke, aerosols, wood smoke, car exhaust), chemicals in the home or workplace, a woman's menses, or physical activity.
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. The National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
American Academy of Allergy, Asthma, and Immunology
(www.aaaai.org)
National Heart, Lung, and Blood Institute
(www.nhlbi.nih.gov/)
National Lung Health Education Program
(www.nlhep.org)
American Lung Association
(www.lungusa.org)
American College of Allergy, Asthma, and Immunology
(allergy.mcg.edu/)
[1-5]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. National Asthma Education and Prevention Program. Expert Panel Report: Guidelines for the Diagnosis and Management of Asthma Update on Selected Topics--2002. J Allergy Clin Immunol 2002; 110:S141.
2. Platts-Mills, TA, Vervloet, D, Thomas, WR, et al. Indoor allergens and asthma: report of the Third International Workshop. J Allergy Clin Immunol 1997; 100:S2.
3. Sporik, RB, Holgate, ST, Platts-Mills, TAE, Cogswell, J. Exposure to house dust mite allergen (Der p I) and the development of asthma in childhood: A prospective study. N Engl J Med 1990; 323:502.
4. Wood, RA, Johnson, EF, Van Natta, ML, et al. A placebo-controlled trial of a HEPA air cleaner in the treatment of cat allergy. Am J Respir Crit Care Med 1998; 158:115.
5. Cates, CJ, Jefferson, TO, Bara, AI, Rowe, BH. Vaccines for preventing influenza in people with asthma. Cochrane Database Syst Rev 2004; :CD000364.
Not all patients with asthma have the same triggers. Finding out which factors trigger an attack and taking steps to avoid the triggers are important parts of good asthma management.
IDENTIFYING AND MANAGING TRIGGERS — Careful attention to the pattern of asthma symptoms is an important part of identifying triggers. For example, if symptoms occur primarily at home, something in that environment may be involved. If symptoms flare in the spring or fall, an outdoor allergy is more likely to blame.
Additional information about possible asthma triggers can sometimes be gained by using blood tests or skin tests to see if a patient is sensitive (or allergic) to a particular substance.
Once asthma triggers have been identified, the patient has several options: Avoid the trigger entirely. Limit exposure to the trigger if it cannot be completely avoided. If a trigger is encountered in a predictable manner, consult with a healthcare provider about taking an extra dose of medicine before exposure to the trigger. Immunotherapy (allergy shots) can sometimes be helpful.
INDOOR TRIGGERS — Allergens are substances that can produce an allergic reaction and are major triggers in many people with asthma. Sensitivity to indoor allergens is especially common in asthmatics. The most common indoor allergens that affect asthmatics are dust mites, mold, animal danders, and cockroaches. The bedroom of the asthmatic person should be given special consideration because the greatest number of hours are typically spent there. However, to be effective, measures must be made to reduce allergens throughout the entire home.
Dust mites — Dust mites are microscopic organisms that are present in most households. They avoid light and absorb humidity from the atmosphere (ie, they do not drink). Mites may live in bedding, sofas, carpets, or any woven material if the humidity is high enough.
Measures that help limit exposure to dust mites are detailed in Table 2 and include (show table 2) : Create a physical barrier to the source of the mites by covering pillows and mattresses with plastic or another impermeable fabric covers. A potential source of confusion when purchasing bedding covers is the availability of "hypoallergenic" unbleached or organic cotton bedding covers. These do not limit the passage of dust mites and are intended for people who have contact sensitivities to fabric dyes. Decrease the population of dust mites in the home by washing bedding in hot water and removing carpets and stuffed toys; these measures help to reduce nesting areas for mites. Control humidity. Mites thrive in humid environments. Opening windows in dry climates and using air conditioning in humid ones decreases humidity in the home and reduces the number of mites. Moving to or spending more time on upper floors of buildings may help, as upper floors tend to be less humid than lower floors or basements. Household humidity should be below 50 percent if possible. Inexpensive humidity monitors can be purchased at most hardware stores.
Mold — Mold spores can trigger asthma in allergic patients. Mold thrives in damp environments. Area such as air conditioning vents, water traps, refrigerator drip trays, shower stalls, leaky sinks, and damp basements are particularly vulnerable to mold growth if not cleaned regularly.
General measures to reduce mold exposure include the quick repair of any plumbing leaks, removal of bathroom carpeting which is exposed to steam and moisture, and scouring of sinks and tubs at least every four weeks with dilute bleach (1 ounce diluted in one quart of water); mold thrives on soap film that covers tiles and grout. In addition, indoor garbage pails should be regularly disinfected, and an electric dehumidifier should be used to remove moisture from the basement. Old books, newspapers, clothing, and bedding should not be stored in the home. Water damaged carpets should be thrown out because eliminating mold is difficult or impossible, even with thorough cleaning. For an important note about the use of bleach by people with asthma, see below (see "Irritants" below).
Animal danders — Asthma can be triggered by proteins from the "dander," saliva, and urine of common house pets such as cats and dogs. Other warm-blooded animals, such as rodents, birds, and ferrets can also trigger asthma in an allergic individual. Pets without feathers or fur, such as reptiles, turtles, and fish, rarely cause allergy, although deposits of fish food that may build up under the covers of fish tanks are an excellent source of food for dust mite colonies.
Animal dander is made up of the dead skin cells or scales (like dandruff) that are constantly shed by animals. Any breed of dog and cat is capable of being allergenic, although the levels given off by individual animals may vary to some degree. In cats, the protein that causes most people's allergies is found in the cat's saliva, skin glands, and urinary/reproductive tract. Accordingly, short-haired cats are not necessarily less allergenic than long-haired animals, and furless cats give off similar amounts of allergen as furred cats.
If a person with asthma is found to be allergic to a pet, the pet should be removed from the home. Limiting an animal to a certain area in the house is not effective because some allergens are carried on clothing or spread in the air. Once a pet has left a home, careful cleaning of carpets, sofas, curtain, and bedding must follow. This is particularly true for cat allergens, as they are "sticky" and adhere to a variety of indoor surfaces. Even after a cat has been removed from a home and it has been thoroughly cleaned, it can take months for levels of cat allergen to drop . For this reason, it may take months for the allergic person's symptoms to fully reflect the absence of the pet.
If it is not possible to remove the animal, measures can be taken to decrease exposure to the animal dander (show table 3), although none of these methods is as effective as removing the animal.
Cockroaches — Cockroach droppings contain allergens that have been shown to trigger asthma in sensitive individuals. Cockroaches thrive in warm environments with easily accessible food and water. Unfortunately, efforts to control cockroach populations in infested areas are often less than successful. Still, certain measures should be tried, including: Using multiple baited traps or poisons Removing garbage and food waste promptly from the home Washing dishes and cooking utensils immediately after use Removing cockroach debris quickly Eliminating any standing water from leaking faucets or drains
The role of air filters — Air filtering devices, including HEPA and other mechanical filters as well as electrostatic filters, are widely advertised and can be quite costly. These may be marketed as components of heating or cooling systems, as individual units for use in a room or area, or as units that are worn by individuals. None of these filtration devices have been scientifically proven to have a significant impact on asthma symptoms.
One possible explanation for this is that although these devices may clean the air, allergen levels cannot be effectively reduced unless measures are taken to eliminate their source. Thus, air filtration may be a useful adjunct to the measures described above, although we advise directing financial resources and efforts primarily towards eliminating sources of allergens.
CONTROLLING OTHER ASTHMA TRIGGERS — In addition to indoor allergens, other factors may be identified as asthma triggers.
Respiratory infections — Infections that cause airway inflammation can trigger asthma, including colds, influenza (flu), bronchitis, ear infections, sinus infections, and pneumonia. An asthma attack that occurs along with a respiratory infection may be more severe than one that occurs at other times. (See "Patient information: Influenza" and see "Patient information: Pneumonia in adults" and see "Patient information: The common cold in adults").
To reduce the risk of a serious flare related to respiratory infection, a person with asthma should: Call a healthcare provider at the first sign of an infection. Get a flu shot once a year. Get a pneumonia vaccine (if needed based on other risk factors) Wash hands frequently, especially when in contact with an infected person, and avoid contact with infected people when possible. Use treatments prescribed for symptoms, such as nasal steroids and decongestants.
Allergies to food and medicine — Allergy to foods, especially foods containing sulfites (potatoes, shrimp, dried fruit, beer, wine) may trigger asthma in sensitive individuals. A food diary, listing all food and drink and chronicling asthma symptoms, may help isolate sensitivity to a particular food. If a sulfite allergy has been identified, the patient should be sure to read food labels to make sure sulfites are not present.
Sensitivity to medications can also trigger asthma. In particular, aspirin, some other anti-inflammatory drugs such as ibuprofen (Advil®, Motrin®) and naproxen (Aleve®, Anaprox®) and certain beta blocker heart medicines may cause an attack in certain individuals. Acetaminophen (Tylenol®) does not cause symptoms in most aspirin-sensitive patients.
Outdoor allergens — Asthma symptoms that worsen outdoors at certain times of year are likely to be triggered by an allergy to pollen or other plant material. Affected individuals should stay indoors as much as possible during the season when their asthma tends to flare and keep windows closed. Patients should also try to avoid cutting grass, digging around plants, or other outdoor activities that seem to worsen asthma symptoms.
Irritants — A variety of irritants can trigger asthma. Irritants can be found inside or outside, and include: Cigarette smoke and ashes — A person with asthma should never smoke, smoking should not be allowed in the person's home, and second-hand smoke should be avoided whenever possible. (See "Patient information: Smoking cessation"). Aerosol sprays, perfumes — Non-aerosol products should be used, and exposure to offending perfumes avoided. Fireplace smoke and cooking odors — Wood-burning stoves, fireplaces, and pellet stoves should not be used, and cooking areas should be well ventilated. Air pollution, car exhaust, gas fumes — Patients should avoid unnecessary exposure to car exhaust, and outdoor exercise should be avoided when pollution levels are high.
Chemicals — Industrial or occupational exposure to chemicals is responsible for about 15 percent of cases of asthma. If symptoms tend to flare in a workplace where chemicals are in use, the patient and healthcare provider can discuss strategies to limit exposure.
If possible, patients whose asthma is triggered by strong odors should also avoid the use of chlorine and bleach-based cleaning products. If these cleaners are needed to control the growth of mold in the home, efforts should be made to ventilate the area thoroughly during and after use, and if possible, have a non-asthmatic person perform the cleaning.
Menstrual cycle — Worsening of asthma symptoms before or during menstruation has been reported in 20 to 40 percent of women with asthma. The reason for this phenomenon is unclear. Women with hormonally-triggered asthma tend to have more severe asthma than women whose asthma is unaffected by hormonal levels.
The optimal management of menstrual-associated asthma flares has not been determined, although women with a history of this problem are advised to increase their medication if necessary and avoid other potential asthma triggers.
Physical activity — Although exercise can trigger asthma in certain people, it should not be avoided. Exercise strengthens the cardiovascular system and may decrease sensitivity to asthma triggers. To minimize the effects of this trigger, asthmatics should: Take one or 2 puffs from an albuterol inhaler 5 minutes before beginning exercise Start any new exercise regime slowly, gradually building strength and endurance. Warm up gradually at the beginning of each exercise session. Take all medications on schedule. Avoid exercising outdoors in extremely cold weather and cover the mouth and nose with a scarf to help warm the inspired air when temperatures are low.
SUMMARY Asthma is a chronic lung condition that causes inflammation and constriction of the airways and difficulty breathing. Asthma attacks, or worsening of asthma symptoms, can occur after exposure to factors known as triggers (show table 1). Once asthma triggers have been identified, the patient has several options: avoid the trigger entirely, limit exposure to the trigger if it cannot be completely avoided, consult with a healthcare provider about taking an extra dose of medicine before exposure to the trigger, or consider immunotherapy (allergy shots), which can sometimes be helpful. Allergens are substances that can produce an allergic reaction in people who are sensitive (allergic) to them. Sensitivity to indoor allergens is especially common in asthmatics. The most common indoor allergens that affect asthmatics are dust mites, mold, animal danders, and cockroaches. In addition to indoor allergens, other factors may be identified as asthma triggers, including respiratory infections (colds, flu), allergies to food or medicines, outdoor allergens (pollen, grasses), irritants (cigarette smoke, aerosols, wood smoke, car exhaust), chemicals in the home or workplace, a woman's menses, or physical activity.
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. The National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
American Academy of Allergy, Asthma, and Immunology
(www.aaaai.org)
National Heart, Lung, and Blood Institute
(www.nhlbi.nih.gov/)
National Lung Health Education Program
(www.nlhep.org)
American Lung Association
(www.lungusa.org)
American College of Allergy, Asthma, and Immunology
(allergy.mcg.edu/)
[1-5]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. National Asthma Education and Prevention Program. Expert Panel Report: Guidelines for the Diagnosis and Management of Asthma Update on Selected Topics--2002. J Allergy Clin Immunol 2002; 110:S141.
2. Platts-Mills, TA, Vervloet, D, Thomas, WR, et al. Indoor allergens and asthma: report of the Third International Workshop. J Allergy Clin Immunol 1997; 100:S2.
3. Sporik, RB, Holgate, ST, Platts-Mills, TAE, Cogswell, J. Exposure to house dust mite allergen (Der p I) and the development of asthma in childhood: A prospective study. N Engl J Med 1990; 323:502.
4. Wood, RA, Johnson, EF, Van Natta, ML, et al. A placebo-controlled trial of a HEPA air cleaner in the treatment of cat allergy. Am J Respir Crit Care Med 1998; 158:115.
5. Cates, CJ, Jefferson, TO, Bara, AI, Rowe, BH. Vaccines for preventing influenza in people with asthma. Cochrane Database Syst Rev 2004; :CD000364.
ASTHMA Patient information: Pregnancy and asthma
INTRODUCTION — Asthma is the most common condition affecting the lungs during pregnancy. At any given time, up to 8 percent of pregnant women have asthma.
It is normal to worry about how the changes of pregnancy will affect asthma and if asthma and its treatments will harm the baby. With good asthma therapy, most women can breathe easily, have a normal pregnancy, and deliver a healthy baby. Overall, the risk of poorly controlled asthma is much higher than the risk of taking medications to control asthma.
Asthma therapy during pregnancy is most successful when a woman receives regular medical care and follows her treatment plan closely. Before becoming pregnant, women with asthma should learn as much as they can about their condition and talk with their healthcare providers about asthma therapy during pregnancy.
SEVERITY OF SYMPTOMS — The effects of pregnancy on asthma vary from woman to woman. Unfortunately, it is difficult to predict the course that asthma will follow in individual women who become pregnant for the first time. During pregnancy, asthma worsens in one-third of women, improves in one-third, and remains stable in one-third.
Other patterns that have been observed include: Among women whose asthma worsens, worsening is most rapid between weeks 29 and 36 of pregnancy. Asthma is generally less severe during the last month of pregnancy. Labor and delivery are not usually associated with a worsening of asthma. Among women whose asthma improves, the improvement progresses gradually throughout pregnancy. The severity of asthma symptoms in a first pregnancy is often similar in subsequent pregnancies.
Factors affecting risk of attacks — The factors that increase or decrease the risk of asthma attacks during pregnancy are not entirely clear. The likelihood of these attacks is not constant throughout pregnancy; attacks seem to be most likely during weeks 17 through 24 of pregnancy (show figure 1). The cause for this pattern is unknown, but researchers suspect that women may stop using asthma-controlling drugs when they discover that they are pregnant, increasing their risk for attacks.
EFFECTS OF ASTHMA ON PREGNANCY AND BABY — Women who have asthma have a small increase in the risk for certain complications of pregnancy, although the reasons for this are unknown. Compared to women who do not have asthma, women with asthma are slightly more likely to develop high blood pressure and preeclampsia during pregnancy, to have a placental abnormality called placenta previa, to have a premature delivery, and to require a cesarean delivery. Women with asthma are also slightly more likely to have a baby that is small for its age.
However, the vast majority of women with asthma and their babies do NOT have any complications during pregnancy. Good control of asthma during pregnancy reduces the risk of complications.
ASTHMA THERAPY DURING PREGNANCY — Good asthma therapy is essential to ensuring the health of both the mother and the baby. Asthma therapy in pregnant women is very similar to asthma therapy in nonpregnant women. Therapy during pregnancy has several key components, which are most successful when used together:
Monitoring Mother's lung function — Normal lung function is important to a mother's health and to her baby's well-being. Lung function can be monitored in a healthcare provider's office or hospital, although home monitoring often provides important information when asthma symptoms worsen, typically during the night or upon awakening.
Pregnant women can monitor their lung function at home by using a simple device that measures the peak expiratory flow rate (PEFR). Depending on the frequency of attacks, a healthcare provider may recommend measuring this rate twice per day: once upon awakening and again 12 hours later. Decreasing flow rates usually signal a worsening of asthma and a need for more intensive therapy, even if the patient is feeling well. (See "Patient information: How to use a peak flow meter").
Lung function tests performed in the doctor's office are also useful for distinguishing the shortness of breath associated with a worsening of asthma from the normal shortness of breath that many women experience during pregnancy. Baby's well-being — A baby's well-being is carefully monitored during regular medical visits throughout pregnancy. These visits are particularly important for women who have asthma.
Avoiding triggers — Several simple steps can help control environmental factors that worsen asthma and trigger attacks. These include: Avoid exposure to specific allergens, especially pet dander (such as fur or feathers), house dust, and nonspecific irritants, such as tobacco smoke, dust, and pollutants Cover mattresses and pillows with special casings to avoid house dust mites. Avoid sleeping on upholstered furniture (eg, couches, recliners). Pregnant women should not smoke or permit smoking in their home.
(For more information about trigger avoidance, see "Patient information: Trigger avoidance in asthma").
Education — Learning about asthma enables people with this condition to better manage their symptoms, prevent attacks, and react when attacks do occur. This education can be particularly reassuring and useful during pregnancy. Asthma education usually teaches strategies for recognizing the signs and symptoms of asthma, avoiding factors that trigger attacks, correctly using asthma-controlling drugs, and developing an individualized treatment plan for acute attacks.
Drug therapy — With a few exceptions, the drug therapy for asthma during pregnancy is very similar to the drug therapy for asthma at other times during a person's life.
Safety of allergy-controlling drugs — It is difficult to prove that asthma-controlling drugs are completely safe during pregnancy, but evidence from the use of these drugs in pregnant women for many years suggests that most of them probably carry little or no risk for the mother or baby.
It is important to weigh the unknown (but likely small) risks of asthma-controlling drugs against the potentially serious harm of undertreated asthma. In most cases, undertreated asthma poses a far greater risk to both the mother and the baby than the use of asthma-controlling drugs.
Types of asthma drugs — There are many different types of asthma-controlling drugs, and the drug or drugs that your healthcare provider recommends will depend upon many factors. In general, inhaled drugs are usually recommended because there is limited body-wide effects in the mother and the baby. It may be necessary to adjust the type or dose of drugs during pregnancy to compensate for changes in metabolism and the severity of asthma. Bronchodilators — Bronchodilators rapidly relieve asthma symptoms by relaxing the airways. They include albuterol (Proventil®, Ventolin®), metaproterenol (Alupent®), terbutaline, and other drugs. Newer drugs, such as salmeterol (Serevent®) and formoterol (Foradil®), are longer-acting bronchodilators; these have been used less frequently during pregnancy, so assessment of potential risk to the unborn baby is more difficult.
Bronchodilators appear to be safe during pregnancy. One study showed that the babies of women who used these drugs during pregnancy had no increase in health problems when compared to the babies of mothers who did not. About 70 percent of these women used the bronchodilators during the first trimester of pregnancy (a particularly sensitive time in fetal development), further suggesting that these drugs are safe.
A healthcare provider may avoid giving bronchodilator pills near the time of delivery because they can weaken uterine contractions. Corticosteroids — Corticosteroids are used to treat many conditions in addition to asthma. Experience from their use in pregnant women suggests that these drugs are generally safe for both the mother and the baby. The corticosteroids include pills such as prednisone and inhaled drugs such as beclomethasone (Beclovent®, Vanceril®, and others), triamcinolone (Azmacort®), flunisolide (AeroBid®), budesonide (Pulmicort®), and fluticasone (Flovent®).
- Oral corticosteroids - Some studies have suggested that there may be an increased risk of cleft lip or cleft palate in the babies of mothers who took oral steroid medications during the first trimester of pregnancy, although these results are not definitive. Two studies found a slightly increased risk of premature delivery, and one study found a slightly increased risk of having a low birth weight baby. However, the researchers could not rule out the possibility that these effects were related to the severity of asthma and not to the use of the drug. In very rare cases, a mother's use of corticosteroids may cause adrenal insufficiency (poor function of the adrenal glands) in the baby at the time of birth, but this condition can be treated and resolves over time.
Women who use corticosteroid pills during pregnancy may be more likely to develop gestational diabetes and high blood pressure, but these conditions can be detected and managed with regular medical visits.
Any of the above risks are probably smaller than the risk of not treating severe asthma, which could be life-threatening for the mother and the baby.
- Inhaled corticosteroids - The information about inhaled corticosteroids is quite reassuring. A variety of inhaled corticosteroids have been used during pregnancy. Budesonide is thought to be one of the safest inhaled corticosteroids. Beclomethasone has also been used extensively during pregnancy. Theophylline — Theophylline (Slo-bid®, Theo-Dur®, and others) has been used for many years during pregnancy without any apparent complications, suggesting that it is safe during pregnancy. As examples, one study of 193 women who took theophylline during pregnancy found no increase in complications; another study found that the risk of stillbirth was no greater in women who took these drugs than in women who did not.
The physiologic changes of pregnancy alter the body's metabolism of theophylline, frequently requiring an adjustment of the dosage. Theophylline, like the beta agonist bronchodilators, can block uterine contractions when taken near delivery. It may also cause a rapid heart beat and fussiness in the baby at the time of delivery, but these effects are usually short-lived. Theophylline can worsen symptoms of heartburn and nausea in the mother; another medicine may be preferred if these symptoms occur.
Since the introduction of the inhaled corticosteroids, theophylline is used less often for asthma in general, including during pregnancy. Inhaled corticosteroids have been shown to be more effective and to cause fewer side effects than theophylline. Cromolyn sodium — There was no increase in birth defects or other pregnancy complications in one study of women who took cromolyn sodium during pregnancy. Although it appears to be a very safe drug, it is not as effective in controlling asthma as inhaled corticosteroids Drugs that affect the leukotriene pathway — Some drugs help control asthma by blocking the leukotriene pathway, which plays an important role in asthma. These drugs include zafirlukast (Accolate®), montelukast (Singulair®), and zileuton (Zyflo™). Studies in animals suggest that zafirlukast and montelukast do not cause birth defects when taken during pregnancy, but there are no studies on the safety of these drugs during pregnancy. Little is known about the safety of zileuton in pregnant women, but it does increase the risk of pregnancy complications in animals and is not generally recommended for use during pregnancy. Antihistamines — Although antihistamines are not used to directly treat asthma, they may be used to treat the allergies that often accompany asthma. These drugs include chlorpheniramine (Chlor-Trimeton® and others), loratadine (Claritin®), fexofenadine (Allegra®), and cetirizine (Zyrtec®). Studies in both animals and humans suggest that antihistamines cause no increase or only a very small increase in the risk for birth defects when taken during pregnancy. Of the currently available preparations, chlorpheniramine (which can be sedating), loratadine, or cetirizine are considered the antihistamines of choice for use during pregnancy. Decongestants — Decongestants are not used for the treatment of asthma, but they may be used to treat the symptoms of upper airway allergies. Pseudoephedrine (Sudafed®) is a decongestant that is commonly available. Most studies examining the safety of decongestants during pregnancy have been small, making it difficult to draw clear-cut conclusions. Until more information is available, it would probably be best to avoid the use of any oral decongestants during the first trimester of pregnancy. After the first trimester, the use of pseudoephedrine is thought to be safe in women without high blood pressure. Immunotherapy — Immunotherapy refers to regular injections (allergy shots) given to reduce a person's sensitivity to allergens. This therapy appears to be safe during pregnancy, although it carries a very small risk of a severe allergic reaction (anaphylaxis) in any patient, including pregnant women.
It is probably safe for women who are already receiving immunotherapy to continue receiving shots during pregnancy. Women who are not receiving immunotherapy at the time they become pregnant generally should not start immunotherapy until after delivery.
Labor, delivery, and the postpartum period — Pregnant women with asthma should discuss their labor and delivery plans with their healthcare provider. Asthma will affect a provider's choice of medications commonly used during labor, delivery, and the postpartum period.
Women with asthma can be treated with the drug oxytocin (Pitocin®) to induce labor and to control bleeding after delivery. During labor and delivery, epidural anesthesia is preferred over general anesthesia for women with asthma because epidural anesthesia reduces the demands on the lungs. If general anesthesia becomes necessary, doctors select specific general anesthetics that promote dilation of airways. The painkillers morphine and meperidine (Demerol®) are usually not recommended for women with asthma because these drugs can cause a release of histamine and worsen an asthma attack, but the painkillers butorphanol (Stadol®) or fentanyl (Sublimaze®) are safe and effective alternatives.
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
American Lung Association
(www.lungusa.org)
Canadian Lung Association
(www.lung.ca)
American Academy of Allergy, Asthma, and Immunology
(www.aaaai.org/patients.stm)
National Heart, Lung, and Blood Institute
(www.nhlbi.nih.gov/health/prof/lung/asthma/astpreg.htm)
[1-5]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Demissie, K, Breckenridge, MB, Rhoads, CG. Infant and maternal outcomes in the pregnancies of asthmatic women. Am J Respir Crit Care Med 1998; 158:1095.
2. Minerbi-Codish, I, Fraser, D, Avnun, L, et al. Influence of asthma in pregnancy on labor and the newborn. Respiration 1998; 65:130.
3. National Asthma Education Program: Report of the Working Group on Asthma and Pregnancy. Management of asthma during pregnancy. National Institutes of Health (NIH publication no. 933279A), Bethesda, MD, 1993. (www.nhlbi.nih.gov/health/prof/lung/asthma/astpreg.txt).
4. Schatz, M. Asthma and pregnancy. Lancet 1999; 353:1202.
5. Wendel, PJ, Ramin, SM, Barnett-Hamm, C, et al. Asthma treatment in pregnancy. A randomized controlled study. Am J Obstet Gynecol 1996; 175:150.
It is normal to worry about how the changes of pregnancy will affect asthma and if asthma and its treatments will harm the baby. With good asthma therapy, most women can breathe easily, have a normal pregnancy, and deliver a healthy baby. Overall, the risk of poorly controlled asthma is much higher than the risk of taking medications to control asthma.
Asthma therapy during pregnancy is most successful when a woman receives regular medical care and follows her treatment plan closely. Before becoming pregnant, women with asthma should learn as much as they can about their condition and talk with their healthcare providers about asthma therapy during pregnancy.
SEVERITY OF SYMPTOMS — The effects of pregnancy on asthma vary from woman to woman. Unfortunately, it is difficult to predict the course that asthma will follow in individual women who become pregnant for the first time. During pregnancy, asthma worsens in one-third of women, improves in one-third, and remains stable in one-third.
Other patterns that have been observed include: Among women whose asthma worsens, worsening is most rapid between weeks 29 and 36 of pregnancy. Asthma is generally less severe during the last month of pregnancy. Labor and delivery are not usually associated with a worsening of asthma. Among women whose asthma improves, the improvement progresses gradually throughout pregnancy. The severity of asthma symptoms in a first pregnancy is often similar in subsequent pregnancies.
Factors affecting risk of attacks — The factors that increase or decrease the risk of asthma attacks during pregnancy are not entirely clear. The likelihood of these attacks is not constant throughout pregnancy; attacks seem to be most likely during weeks 17 through 24 of pregnancy (show figure 1). The cause for this pattern is unknown, but researchers suspect that women may stop using asthma-controlling drugs when they discover that they are pregnant, increasing their risk for attacks.
EFFECTS OF ASTHMA ON PREGNANCY AND BABY — Women who have asthma have a small increase in the risk for certain complications of pregnancy, although the reasons for this are unknown. Compared to women who do not have asthma, women with asthma are slightly more likely to develop high blood pressure and preeclampsia during pregnancy, to have a placental abnormality called placenta previa, to have a premature delivery, and to require a cesarean delivery. Women with asthma are also slightly more likely to have a baby that is small for its age.
However, the vast majority of women with asthma and their babies do NOT have any complications during pregnancy. Good control of asthma during pregnancy reduces the risk of complications.
ASTHMA THERAPY DURING PREGNANCY — Good asthma therapy is essential to ensuring the health of both the mother and the baby. Asthma therapy in pregnant women is very similar to asthma therapy in nonpregnant women. Therapy during pregnancy has several key components, which are most successful when used together:
Monitoring Mother's lung function — Normal lung function is important to a mother's health and to her baby's well-being. Lung function can be monitored in a healthcare provider's office or hospital, although home monitoring often provides important information when asthma symptoms worsen, typically during the night or upon awakening.
Pregnant women can monitor their lung function at home by using a simple device that measures the peak expiratory flow rate (PEFR). Depending on the frequency of attacks, a healthcare provider may recommend measuring this rate twice per day: once upon awakening and again 12 hours later. Decreasing flow rates usually signal a worsening of asthma and a need for more intensive therapy, even if the patient is feeling well. (See "Patient information: How to use a peak flow meter").
Lung function tests performed in the doctor's office are also useful for distinguishing the shortness of breath associated with a worsening of asthma from the normal shortness of breath that many women experience during pregnancy. Baby's well-being — A baby's well-being is carefully monitored during regular medical visits throughout pregnancy. These visits are particularly important for women who have asthma.
Avoiding triggers — Several simple steps can help control environmental factors that worsen asthma and trigger attacks. These include: Avoid exposure to specific allergens, especially pet dander (such as fur or feathers), house dust, and nonspecific irritants, such as tobacco smoke, dust, and pollutants Cover mattresses and pillows with special casings to avoid house dust mites. Avoid sleeping on upholstered furniture (eg, couches, recliners). Pregnant women should not smoke or permit smoking in their home.
(For more information about trigger avoidance, see "Patient information: Trigger avoidance in asthma").
Education — Learning about asthma enables people with this condition to better manage their symptoms, prevent attacks, and react when attacks do occur. This education can be particularly reassuring and useful during pregnancy. Asthma education usually teaches strategies for recognizing the signs and symptoms of asthma, avoiding factors that trigger attacks, correctly using asthma-controlling drugs, and developing an individualized treatment plan for acute attacks.
Drug therapy — With a few exceptions, the drug therapy for asthma during pregnancy is very similar to the drug therapy for asthma at other times during a person's life.
Safety of allergy-controlling drugs — It is difficult to prove that asthma-controlling drugs are completely safe during pregnancy, but evidence from the use of these drugs in pregnant women for many years suggests that most of them probably carry little or no risk for the mother or baby.
It is important to weigh the unknown (but likely small) risks of asthma-controlling drugs against the potentially serious harm of undertreated asthma. In most cases, undertreated asthma poses a far greater risk to both the mother and the baby than the use of asthma-controlling drugs.
Types of asthma drugs — There are many different types of asthma-controlling drugs, and the drug or drugs that your healthcare provider recommends will depend upon many factors. In general, inhaled drugs are usually recommended because there is limited body-wide effects in the mother and the baby. It may be necessary to adjust the type or dose of drugs during pregnancy to compensate for changes in metabolism and the severity of asthma. Bronchodilators — Bronchodilators rapidly relieve asthma symptoms by relaxing the airways. They include albuterol (Proventil®, Ventolin®), metaproterenol (Alupent®), terbutaline, and other drugs. Newer drugs, such as salmeterol (Serevent®) and formoterol (Foradil®), are longer-acting bronchodilators; these have been used less frequently during pregnancy, so assessment of potential risk to the unborn baby is more difficult.
Bronchodilators appear to be safe during pregnancy. One study showed that the babies of women who used these drugs during pregnancy had no increase in health problems when compared to the babies of mothers who did not. About 70 percent of these women used the bronchodilators during the first trimester of pregnancy (a particularly sensitive time in fetal development), further suggesting that these drugs are safe.
A healthcare provider may avoid giving bronchodilator pills near the time of delivery because they can weaken uterine contractions. Corticosteroids — Corticosteroids are used to treat many conditions in addition to asthma. Experience from their use in pregnant women suggests that these drugs are generally safe for both the mother and the baby. The corticosteroids include pills such as prednisone and inhaled drugs such as beclomethasone (Beclovent®, Vanceril®, and others), triamcinolone (Azmacort®), flunisolide (AeroBid®), budesonide (Pulmicort®), and fluticasone (Flovent®).
- Oral corticosteroids - Some studies have suggested that there may be an increased risk of cleft lip or cleft palate in the babies of mothers who took oral steroid medications during the first trimester of pregnancy, although these results are not definitive. Two studies found a slightly increased risk of premature delivery, and one study found a slightly increased risk of having a low birth weight baby. However, the researchers could not rule out the possibility that these effects were related to the severity of asthma and not to the use of the drug. In very rare cases, a mother's use of corticosteroids may cause adrenal insufficiency (poor function of the adrenal glands) in the baby at the time of birth, but this condition can be treated and resolves over time.
Women who use corticosteroid pills during pregnancy may be more likely to develop gestational diabetes and high blood pressure, but these conditions can be detected and managed with regular medical visits.
Any of the above risks are probably smaller than the risk of not treating severe asthma, which could be life-threatening for the mother and the baby.
- Inhaled corticosteroids - The information about inhaled corticosteroids is quite reassuring. A variety of inhaled corticosteroids have been used during pregnancy. Budesonide is thought to be one of the safest inhaled corticosteroids. Beclomethasone has also been used extensively during pregnancy. Theophylline — Theophylline (Slo-bid®, Theo-Dur®, and others) has been used for many years during pregnancy without any apparent complications, suggesting that it is safe during pregnancy. As examples, one study of 193 women who took theophylline during pregnancy found no increase in complications; another study found that the risk of stillbirth was no greater in women who took these drugs than in women who did not.
The physiologic changes of pregnancy alter the body's metabolism of theophylline, frequently requiring an adjustment of the dosage. Theophylline, like the beta agonist bronchodilators, can block uterine contractions when taken near delivery. It may also cause a rapid heart beat and fussiness in the baby at the time of delivery, but these effects are usually short-lived. Theophylline can worsen symptoms of heartburn and nausea in the mother; another medicine may be preferred if these symptoms occur.
Since the introduction of the inhaled corticosteroids, theophylline is used less often for asthma in general, including during pregnancy. Inhaled corticosteroids have been shown to be more effective and to cause fewer side effects than theophylline. Cromolyn sodium — There was no increase in birth defects or other pregnancy complications in one study of women who took cromolyn sodium during pregnancy. Although it appears to be a very safe drug, it is not as effective in controlling asthma as inhaled corticosteroids Drugs that affect the leukotriene pathway — Some drugs help control asthma by blocking the leukotriene pathway, which plays an important role in asthma. These drugs include zafirlukast (Accolate®), montelukast (Singulair®), and zileuton (Zyflo™). Studies in animals suggest that zafirlukast and montelukast do not cause birth defects when taken during pregnancy, but there are no studies on the safety of these drugs during pregnancy. Little is known about the safety of zileuton in pregnant women, but it does increase the risk of pregnancy complications in animals and is not generally recommended for use during pregnancy. Antihistamines — Although antihistamines are not used to directly treat asthma, they may be used to treat the allergies that often accompany asthma. These drugs include chlorpheniramine (Chlor-Trimeton® and others), loratadine (Claritin®), fexofenadine (Allegra®), and cetirizine (Zyrtec®). Studies in both animals and humans suggest that antihistamines cause no increase or only a very small increase in the risk for birth defects when taken during pregnancy. Of the currently available preparations, chlorpheniramine (which can be sedating), loratadine, or cetirizine are considered the antihistamines of choice for use during pregnancy. Decongestants — Decongestants are not used for the treatment of asthma, but they may be used to treat the symptoms of upper airway allergies. Pseudoephedrine (Sudafed®) is a decongestant that is commonly available. Most studies examining the safety of decongestants during pregnancy have been small, making it difficult to draw clear-cut conclusions. Until more information is available, it would probably be best to avoid the use of any oral decongestants during the first trimester of pregnancy. After the first trimester, the use of pseudoephedrine is thought to be safe in women without high blood pressure. Immunotherapy — Immunotherapy refers to regular injections (allergy shots) given to reduce a person's sensitivity to allergens. This therapy appears to be safe during pregnancy, although it carries a very small risk of a severe allergic reaction (anaphylaxis) in any patient, including pregnant women.
It is probably safe for women who are already receiving immunotherapy to continue receiving shots during pregnancy. Women who are not receiving immunotherapy at the time they become pregnant generally should not start immunotherapy until after delivery.
Labor, delivery, and the postpartum period — Pregnant women with asthma should discuss their labor and delivery plans with their healthcare provider. Asthma will affect a provider's choice of medications commonly used during labor, delivery, and the postpartum period.
Women with asthma can be treated with the drug oxytocin (Pitocin®) to induce labor and to control bleeding after delivery. During labor and delivery, epidural anesthesia is preferred over general anesthesia for women with asthma because epidural anesthesia reduces the demands on the lungs. If general anesthesia becomes necessary, doctors select specific general anesthetics that promote dilation of airways. The painkillers morphine and meperidine (Demerol®) are usually not recommended for women with asthma because these drugs can cause a release of histamine and worsen an asthma attack, but the painkillers butorphanol (Stadol®) or fentanyl (Sublimaze®) are safe and effective alternatives.
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
American Lung Association
(www.lungusa.org)
Canadian Lung Association
(www.lung.ca)
American Academy of Allergy, Asthma, and Immunology
(www.aaaai.org/patients.stm)
National Heart, Lung, and Blood Institute
(www.nhlbi.nih.gov/health/prof/lung/asthma/astpreg.htm)
[1-5]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Demissie, K, Breckenridge, MB, Rhoads, CG. Infant and maternal outcomes in the pregnancies of asthmatic women. Am J Respir Crit Care Med 1998; 158:1095.
2. Minerbi-Codish, I, Fraser, D, Avnun, L, et al. Influence of asthma in pregnancy on labor and the newborn. Respiration 1998; 65:130.
3. National Asthma Education Program: Report of the Working Group on Asthma and Pregnancy. Management of asthma during pregnancy. National Institutes of Health (NIH publication no. 933279A), Bethesda, MD, 1993. (www.nhlbi.nih.gov/health/prof/lung/asthma/astpreg.txt).
4. Schatz, M. Asthma and pregnancy. Lancet 1999; 353:1202.
5. Wendel, PJ, Ramin, SM, Barnett-Hamm, C, et al. Asthma treatment in pregnancy. A randomized controlled study. Am J Obstet Gynecol 1996; 175:150.
ASTHMA Patient information: Overview of managing asthma
INTRODUCTION — Asthma is a common lung disease affecting millions of people worldwide. It is caused by narrowing of the small airways (tubes) in the lungs. This narrowing is usually reversible, but may occasionally become permanent over time. Many different genetic and environmental factors play a role in causing asthma. Symptoms of asthma include wheezing, coughing, chest tightness, and shortness of breath. These symptoms tend to come and go, and are related to the degree of airway narrowing in the lungs.
A number of different medicines are useful in treating asthma, but not all asthma medicines are appropriate for every patient. Medicines used to treat asthma vary in cost, method of delivery, and potential side effects. Patients are affected differently by asthma, so patients, doctors, and other health care professionals must work together to develop an individualized treatment plan.
The purpose of asthma treatment is to manage the disease in order to live as normal a life as possible. This requires being well educated about the disease and being an active player in managing it. Most people with asthma are successful in controlling the disease.
The severity of asthma is an important factor in determining an asthma treatment plan. Asthma is generally classified as mild, moderate, or severe based on history of the disease, studies of lung function, and medication use. A patient's history includes frequency and severity of symptoms that occur with activities of daily living, such as walking, running, climbing stairs, carrying packages up stairs, and sleeping. The majority of people with asthma have a mild case (show table 1).
Successful management of asthma involves four components: Understanding the disease and how to treat it Controlling things that trigger asthma Regularly monitoring symptoms and lung function Medication
CONTROLLING ASTHMA TRIGGERS — The factors that set off and exacerbate asthma symptoms are called "triggers." Identifying and avoiding asthma triggers is essential in preventing asthma flare-ups. Common triggers generally fall into several categories: Allergens (including dust and animal fur) Respiratory infections Irritants (such as smoke or chemicals) Physical activity Emotional stress Menstrual cycle in women
A small number of patients will develop asthmatic symptoms after exposure to aspirin or other nonsteroidal antiinflammatory medications, like ibuprofen or naproxen. (See "Patient information: Trigger avoidance in asthma").
After identifying potential asthma triggers, a patient and their clinician should develop a plan to deal with the triggers. There are three main options: Avoid the trigger entirely (eg, if allergic to animals, do not own pets, or if asthma is triggered by dust, have someone else do the house cleaning) Limit exposure to the trigger if it cannot be completely avoided (eg, move to another seat if someone with strong perfume is seated nearby) Take an extra dose of bronchodilator medication before exposure to a trigger. Talk with a healthcare provider before using this approach; it should only be used if the first two options are not possible. Be careful not to use more than twice the amount of medication normally used.
MONITORING SYMPTOMS AND LUNG FUNCTION — Successful management of asthma relies on a patient's ability to monitor their condition regularly. This is done by recording the frequency and severity of symptoms (such as wheezing, coughing, and shortness of breath) and by obtaining numerical measurements of lung function, such as peak expiratory flow rates (PEFRs).
Peak expiratory flow rate — PEFR measures the rate at which a patient can exhale. This rate is dependent on the degree of airway narrowing. PEFR monitoring can provide firm data that can be used to make treatment decisions. The National Asthma Education and Prevention Program recommends that people with moderate to severe persistent asthma use a peak flow meter daily to monitor their lung function. PEFR measurement can be used to monitor lung function and response to treatment, assess the severity of asthma attacks, and guide decisions regarding treatment.
Peak flow meters are inexpensive and easy to use. PEFR is usually measured when getting up in the morning and before going to bed at night. For more information, see "Patient Information: How to use a peak flow meter".
Asthma diary — Using an asthma diary to record daily peak flow readings and asthma symptoms can help patients to identify a cause-and-effect relationship between exposure to certain asthma triggers, decreases in peak flow, and exacerbations of asthma. The diary can also help track medication use (show figure 1).
TREATMENT — Medication is the main form of treatment for most people in managing asthma. The medications used vary according to the type and severity of asthma. An individual's asthma treatment plan must constantly be adjusted because the severity of the disorder changes over time. As symptoms improve, medication should be reduced. As symptoms worsen, medication should be increased.
Mild intermittent asthma — People with mild intermittent asthma are defined in part as those who have: Symptoms of asthma occurring two or fewer times per week Two or fewer awakenings during the night per month Peak flow measurements when asymptomatic that are consistently within the normal range (ie, PEFR >80 percent of predicted normal)
In addition, a person with asthma that is triggered only during vigorous exercise (exercise-induced asthma) might fit into this category even if exercising more than twice per week. Others in whom asthmatic symptoms arise only under certain infrequently occurring circumstances (eg, when exposed to a cat or during some viral respiratory tract infections) are also considered to have mild intermittent asthma.
Bronchodilators — People with mild intermittent asthma have the mildest form of asthma and require treatment with bronchodilators (called beta agonists) only occasionally. Bronchodilators are medicines that help open the narrowed airways of patients with asthma. Although patients with mild intermittent asthma can take bronchodilators on a regularly scheduled basis without harmful effects, there is no advantage over taking them only when needed.
The preferred way of taking medication for people with mild intermittent asthma is using an inhaler. This method allows the medication to take effect rapidly with maximum strength and minimal side effects. People who can predict triggers of asthma symptoms (eg, exercise-induced symptoms) are encouraged to use their inhalers approximately 10 minutes before exposure in order to prevent symptoms from occurring. Inhaled beta agonists can also relieve symptoms after they have started. (See "Patient Information: Metered dose inhaler techniques" for information on how to use an inhaler).
Some people experience tremulousness, palpitations, and/or anxiety from inhaled beta agonists. Using a single inhalation of the medication for prevention or relief of symptoms rather than the usual two puffs may alleviate these reactions with a minimal decrease in benefit.
Mast cell stabilizers — Mast cell stabilizing medications, such as cromolyn (Intal®) and nedocromil (Tilade®), are alternate medications for prevention of exercise-induced symptoms. Two inhalations of either medication taken about 10 to 20 minutes before exercising can provide effective preventive treatment with no side effects. However, they cannot relieve symptoms that have already started. These medications provide additive protection when used with a beta agonist before exercising.
Mild persistent asthma — People with mild persistent asthma have symptoms regularly but not every day. Although they have days with some limitation in their activities, they are typically not restricted. They may be awakened from sleep three to four times a month by symptoms but most nights they sleep well. Lung function is usually normal between episodes but becomes abnormal during an asthma attack.
It is useful to start regular treatment with antiinflammatory medications when a person has one of the following: Symptoms requiring relief with an inhaled bronchodilator more than twice a week Awakenings during the night more often than twice a month Changes in PEFR of more than 20 percent
Antiinflammatory medications — Regular treatment with antiinflammatory medications reduces the frequency of symptoms (and the need for inhaled bronchodilators for symptom relief), improves quality of life, and decreases the risk of serious exacerbations. By reducing over-responsiveness of the bronchial tubes, regular antiinflammatory treatment change the basic condition of the airways that causes asthma and reduces a patient's exaggerated sensitivity to asthma triggers.
For adults, the most frequently recommended type of antiinflammatory medication is an inhaled corticosteroid. It is usually taken twice a day. People who are taking antiinflammatory medication regularly should continue to use their inhaled bronchodilator as needed for relief of symptoms and before exposure to their asthma triggers. Side effects — The most common side effect from this type of medication is oral candidiasis (thrush). This complication is infrequent when inhaled corticosteroids are taken with a spacer (which helps to deliver medication to the lungs rather than the mouth) and if the patient rinses their mouth immediately after inhalation.
Hoarse voice and sore throat (without thrush) are less common side effects that usually resolve quickly after temporarily stopping the medication. If inhalation causes coughing with each use, changing to a different steroid preparation may relieve the problem.
Leukotriene blockers — A separate category of medications called leukotriene blockers provides an alternative to inhaled steroids in patients with mild persistent asthma. They are in pill form, are taken by mouth once or twice daily, and have very few side effects. However, compared to inhaled corticosteroids they are somewhat less effective in controlling asthma and are more expensive.
Moderate persistent asthma — The presence of any of the following is an indication of moderate asthma: Daily symptoms Daily need for bronchodilator medications Asthma attacks that interfere with daily activities Awakening during the night more than once per week PEFR 60 to 80 percent of normal
Controller medications — Patients who have moderate persistent asthma often need to use medicines on a daily basis to keep their asthma under control. For these patients, controller medicines are important, and should be used regularly even if there are no symptoms of active asthma. Controller medicines work over time to decrease the amount of inflammation (or narrowing) of the small airways. Some controller medicines are delivered by inhaler while others are taken by mouth. Controller medicines include long-acting bronchodilators, inhaled or oral steroids, and oral leukotriene modifiers like montelukast (Singulair®)
Many people whose asthma is poorly controlled on low doses of inhaled corticosteroids improve when the dose is raised. If they have moderate persistent asthma, they should use a dose at the high end of the medium dose range. They should also use quick-acting beta agonists for relief of sudden onset symptoms.
If symptoms continue several weeks after starting inhaled corticosteroids at the high end of the medium dose range, a second controller medication should be added. These include salmeterol (contained in Advair®), montelukast (Singulair®) zafirlukast (Accolate®) or sustained release theophylline. Side effects — As the dose of inhaled corticosteroids is increased, the likelihood of systemic absorption and the chance for significant side effects from long-term use increase. Side effects from long-term use may include: Increased pressure in the eye Cataracts Growth retardation Increased bone loss
The risk of these complications is far less with inhaled corticosteroids than with oral corticosteroids. Nevertheless, in patients with moderate or severe asthma whose disease has been well controlled with high-dose inhaled corticosteroids, every effort should be made to reduce the dose to as low as possible while maintaining good asthma control and minimizing the risk of exacerbations.
Severe asthma — The following are indications of severe chronic asthma: Frequent asthma exacerbations as a result of minor exposures to viral illnesses, allergens, exercise, or air pollutants Awakenings from sleep four to seven nights per week PEFR below 60 percent of predicted normal Inability to achieve normal lung function despite chronic treatment with multiple medications, including inhaled steroids at moderate to high dose, or continuous, every other day, or multiple short courses of oral steroids.
People with severe asthma usually require multiple controller medications and bronchodilator medications on a regular basis. If they cannot achieve symptom control with two controller medications, they are likely to require the addition of oral corticosteroids or high-dose inhaled corticosteroids. Consultation with an asthma specialist is warranted in cases of severe asthma.
ASTHMA IN PREGNANCY — Asthma is the most common condition that affects the lungs during pregnancy. About 4 percent of pregnant women have asthma. With good asthma treatment during pregnancy, most women can breathe easily, have a normal pregnancy, and give birth to a healthy baby.
Before becoming pregnant, women with asthma should learn as much as they can about the condition and talk with their doctors about asthma treatment during pregnancy. More information about asthma during pregnancy is presented separately. (See "Patient Information: Pregnancy and asthma").
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. The National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
National Heart, Lung, and Blood Institute
(www.nhlbi.nih.gov/)
American Lung Association
(www.lungusa.org)
What's Asthma All About?
(www.whatsasthma.org)
The Asthma and Allergy Foundation of America
(www.aafa.org)
American Academy of Allergy, Asthma, and Immunology
(www.aaaai.org/patients.stm)
American College of Allergy, Asthma, and Immunology
(www.acaai.org/public/)
[1-3]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Worldwide variation in prevalence of symptoms of asthma, allergic rhinoconjunctivitis, and atopic eczema: ISAAC. The International Study of Asthma and Allergies in Childhood (ISAAC) Steering Committee. Lancet 1998; 351:1225.
2. National Asthma Education Program Expert Panel. Guidelines for the diagnosis and management of asthma. US Department of Health and Human Services, National Institutes of Health, Bethesda, 1997.
3. National Asthma Education and Prevention Program Expert Panel Executive Summary Report: Guidelines for the Diagnosis and Management of Asthma - Update on Selected Topics 2002. National Institutes of Health, National Heart, Lung, and Blood Institute, Publication No. 02-5075, 2002. Full text available online: www.nhlbi.nih.gov/guidelines/asthma/asthgdln.pdf (Accessed 3/7/05).
A number of different medicines are useful in treating asthma, but not all asthma medicines are appropriate for every patient. Medicines used to treat asthma vary in cost, method of delivery, and potential side effects. Patients are affected differently by asthma, so patients, doctors, and other health care professionals must work together to develop an individualized treatment plan.
The purpose of asthma treatment is to manage the disease in order to live as normal a life as possible. This requires being well educated about the disease and being an active player in managing it. Most people with asthma are successful in controlling the disease.
The severity of asthma is an important factor in determining an asthma treatment plan. Asthma is generally classified as mild, moderate, or severe based on history of the disease, studies of lung function, and medication use. A patient's history includes frequency and severity of symptoms that occur with activities of daily living, such as walking, running, climbing stairs, carrying packages up stairs, and sleeping. The majority of people with asthma have a mild case (show table 1).
Successful management of asthma involves four components: Understanding the disease and how to treat it Controlling things that trigger asthma Regularly monitoring symptoms and lung function Medication
CONTROLLING ASTHMA TRIGGERS — The factors that set off and exacerbate asthma symptoms are called "triggers." Identifying and avoiding asthma triggers is essential in preventing asthma flare-ups. Common triggers generally fall into several categories: Allergens (including dust and animal fur) Respiratory infections Irritants (such as smoke or chemicals) Physical activity Emotional stress Menstrual cycle in women
A small number of patients will develop asthmatic symptoms after exposure to aspirin or other nonsteroidal antiinflammatory medications, like ibuprofen or naproxen. (See "Patient information: Trigger avoidance in asthma").
After identifying potential asthma triggers, a patient and their clinician should develop a plan to deal with the triggers. There are three main options: Avoid the trigger entirely (eg, if allergic to animals, do not own pets, or if asthma is triggered by dust, have someone else do the house cleaning) Limit exposure to the trigger if it cannot be completely avoided (eg, move to another seat if someone with strong perfume is seated nearby) Take an extra dose of bronchodilator medication before exposure to a trigger. Talk with a healthcare provider before using this approach; it should only be used if the first two options are not possible. Be careful not to use more than twice the amount of medication normally used.
MONITORING SYMPTOMS AND LUNG FUNCTION — Successful management of asthma relies on a patient's ability to monitor their condition regularly. This is done by recording the frequency and severity of symptoms (such as wheezing, coughing, and shortness of breath) and by obtaining numerical measurements of lung function, such as peak expiratory flow rates (PEFRs).
Peak expiratory flow rate — PEFR measures the rate at which a patient can exhale. This rate is dependent on the degree of airway narrowing. PEFR monitoring can provide firm data that can be used to make treatment decisions. The National Asthma Education and Prevention Program recommends that people with moderate to severe persistent asthma use a peak flow meter daily to monitor their lung function. PEFR measurement can be used to monitor lung function and response to treatment, assess the severity of asthma attacks, and guide decisions regarding treatment.
Peak flow meters are inexpensive and easy to use. PEFR is usually measured when getting up in the morning and before going to bed at night. For more information, see "Patient Information: How to use a peak flow meter".
Asthma diary — Using an asthma diary to record daily peak flow readings and asthma symptoms can help patients to identify a cause-and-effect relationship between exposure to certain asthma triggers, decreases in peak flow, and exacerbations of asthma. The diary can also help track medication use (show figure 1).
TREATMENT — Medication is the main form of treatment for most people in managing asthma. The medications used vary according to the type and severity of asthma. An individual's asthma treatment plan must constantly be adjusted because the severity of the disorder changes over time. As symptoms improve, medication should be reduced. As symptoms worsen, medication should be increased.
Mild intermittent asthma — People with mild intermittent asthma are defined in part as those who have: Symptoms of asthma occurring two or fewer times per week Two or fewer awakenings during the night per month Peak flow measurements when asymptomatic that are consistently within the normal range (ie, PEFR >80 percent of predicted normal)
In addition, a person with asthma that is triggered only during vigorous exercise (exercise-induced asthma) might fit into this category even if exercising more than twice per week. Others in whom asthmatic symptoms arise only under certain infrequently occurring circumstances (eg, when exposed to a cat or during some viral respiratory tract infections) are also considered to have mild intermittent asthma.
Bronchodilators — People with mild intermittent asthma have the mildest form of asthma and require treatment with bronchodilators (called beta agonists) only occasionally. Bronchodilators are medicines that help open the narrowed airways of patients with asthma. Although patients with mild intermittent asthma can take bronchodilators on a regularly scheduled basis without harmful effects, there is no advantage over taking them only when needed.
The preferred way of taking medication for people with mild intermittent asthma is using an inhaler. This method allows the medication to take effect rapidly with maximum strength and minimal side effects. People who can predict triggers of asthma symptoms (eg, exercise-induced symptoms) are encouraged to use their inhalers approximately 10 minutes before exposure in order to prevent symptoms from occurring. Inhaled beta agonists can also relieve symptoms after they have started. (See "Patient Information: Metered dose inhaler techniques" for information on how to use an inhaler).
Some people experience tremulousness, palpitations, and/or anxiety from inhaled beta agonists. Using a single inhalation of the medication for prevention or relief of symptoms rather than the usual two puffs may alleviate these reactions with a minimal decrease in benefit.
Mast cell stabilizers — Mast cell stabilizing medications, such as cromolyn (Intal®) and nedocromil (Tilade®), are alternate medications for prevention of exercise-induced symptoms. Two inhalations of either medication taken about 10 to 20 minutes before exercising can provide effective preventive treatment with no side effects. However, they cannot relieve symptoms that have already started. These medications provide additive protection when used with a beta agonist before exercising.
Mild persistent asthma — People with mild persistent asthma have symptoms regularly but not every day. Although they have days with some limitation in their activities, they are typically not restricted. They may be awakened from sleep three to four times a month by symptoms but most nights they sleep well. Lung function is usually normal between episodes but becomes abnormal during an asthma attack.
It is useful to start regular treatment with antiinflammatory medications when a person has one of the following: Symptoms requiring relief with an inhaled bronchodilator more than twice a week Awakenings during the night more often than twice a month Changes in PEFR of more than 20 percent
Antiinflammatory medications — Regular treatment with antiinflammatory medications reduces the frequency of symptoms (and the need for inhaled bronchodilators for symptom relief), improves quality of life, and decreases the risk of serious exacerbations. By reducing over-responsiveness of the bronchial tubes, regular antiinflammatory treatment change the basic condition of the airways that causes asthma and reduces a patient's exaggerated sensitivity to asthma triggers.
For adults, the most frequently recommended type of antiinflammatory medication is an inhaled corticosteroid. It is usually taken twice a day. People who are taking antiinflammatory medication regularly should continue to use their inhaled bronchodilator as needed for relief of symptoms and before exposure to their asthma triggers. Side effects — The most common side effect from this type of medication is oral candidiasis (thrush). This complication is infrequent when inhaled corticosteroids are taken with a spacer (which helps to deliver medication to the lungs rather than the mouth) and if the patient rinses their mouth immediately after inhalation.
Hoarse voice and sore throat (without thrush) are less common side effects that usually resolve quickly after temporarily stopping the medication. If inhalation causes coughing with each use, changing to a different steroid preparation may relieve the problem.
Leukotriene blockers — A separate category of medications called leukotriene blockers provides an alternative to inhaled steroids in patients with mild persistent asthma. They are in pill form, are taken by mouth once or twice daily, and have very few side effects. However, compared to inhaled corticosteroids they are somewhat less effective in controlling asthma and are more expensive.
Moderate persistent asthma — The presence of any of the following is an indication of moderate asthma: Daily symptoms Daily need for bronchodilator medications Asthma attacks that interfere with daily activities Awakening during the night more than once per week PEFR 60 to 80 percent of normal
Controller medications — Patients who have moderate persistent asthma often need to use medicines on a daily basis to keep their asthma under control. For these patients, controller medicines are important, and should be used regularly even if there are no symptoms of active asthma. Controller medicines work over time to decrease the amount of inflammation (or narrowing) of the small airways. Some controller medicines are delivered by inhaler while others are taken by mouth. Controller medicines include long-acting bronchodilators, inhaled or oral steroids, and oral leukotriene modifiers like montelukast (Singulair®)
Many people whose asthma is poorly controlled on low doses of inhaled corticosteroids improve when the dose is raised. If they have moderate persistent asthma, they should use a dose at the high end of the medium dose range. They should also use quick-acting beta agonists for relief of sudden onset symptoms.
If symptoms continue several weeks after starting inhaled corticosteroids at the high end of the medium dose range, a second controller medication should be added. These include salmeterol (contained in Advair®), montelukast (Singulair®) zafirlukast (Accolate®) or sustained release theophylline. Side effects — As the dose of inhaled corticosteroids is increased, the likelihood of systemic absorption and the chance for significant side effects from long-term use increase. Side effects from long-term use may include: Increased pressure in the eye Cataracts Growth retardation Increased bone loss
The risk of these complications is far less with inhaled corticosteroids than with oral corticosteroids. Nevertheless, in patients with moderate or severe asthma whose disease has been well controlled with high-dose inhaled corticosteroids, every effort should be made to reduce the dose to as low as possible while maintaining good asthma control and minimizing the risk of exacerbations.
Severe asthma — The following are indications of severe chronic asthma: Frequent asthma exacerbations as a result of minor exposures to viral illnesses, allergens, exercise, or air pollutants Awakenings from sleep four to seven nights per week PEFR below 60 percent of predicted normal Inability to achieve normal lung function despite chronic treatment with multiple medications, including inhaled steroids at moderate to high dose, or continuous, every other day, or multiple short courses of oral steroids.
People with severe asthma usually require multiple controller medications and bronchodilator medications on a regular basis. If they cannot achieve symptom control with two controller medications, they are likely to require the addition of oral corticosteroids or high-dose inhaled corticosteroids. Consultation with an asthma specialist is warranted in cases of severe asthma.
ASTHMA IN PREGNANCY — Asthma is the most common condition that affects the lungs during pregnancy. About 4 percent of pregnant women have asthma. With good asthma treatment during pregnancy, most women can breathe easily, have a normal pregnancy, and give birth to a healthy baby.
Before becoming pregnant, women with asthma should learn as much as they can about the condition and talk with their doctors about asthma treatment during pregnancy. More information about asthma during pregnancy is presented separately. (See "Patient Information: Pregnancy and asthma").
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. The National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
National Heart, Lung, and Blood Institute
(www.nhlbi.nih.gov/)
American Lung Association
(www.lungusa.org)
What's Asthma All About?
(www.whatsasthma.org)
The Asthma and Allergy Foundation of America
(www.aafa.org)
American Academy of Allergy, Asthma, and Immunology
(www.aaaai.org/patients.stm)
American College of Allergy, Asthma, and Immunology
(www.acaai.org/public/)
[1-3]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Worldwide variation in prevalence of symptoms of asthma, allergic rhinoconjunctivitis, and atopic eczema: ISAAC. The International Study of Asthma and Allergies in Childhood (ISAAC) Steering Committee. Lancet 1998; 351:1225.
2. National Asthma Education Program Expert Panel. Guidelines for the diagnosis and management of asthma. US Department of Health and Human Services, National Institutes of Health, Bethesda, 1997.
3. National Asthma Education and Prevention Program Expert Panel Executive Summary Report: Guidelines for the Diagnosis and Management of Asthma - Update on Selected Topics 2002. National Institutes of Health, National Heart, Lung, and Blood Institute, Publication No. 02-5075, 2002. Full text available online: www.nhlbi.nih.gov/guidelines/asthma/asthgdln.pdf (Accessed 3/7/05).
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