INTRODUCTION — The management of asthma relies on a patient's ability to monitor their asthma regularly. Self-monitoring includes assessing the frequency and severity of symptoms (such as wheezing and shortness of breath) and measurement of lung function with tests such as a peak expiratory flow rate (PEFR). PEFR provides a number that correlates to how open the lung's airways are; as asthma worsens and the airways narrow, the PEFR decreases. Monitoring can help a patient and their healthcare provider determine the most appropriate asthma treatment plan. (See "Patient information: Overview of managing asthma").
ASTHMA MONITORING RECOMMENDATIONS — The National Asthma Education and Prevention Program (NAEPP) recommends that patients with moderate to severe persistent asthma have a peak flow meter at home and know how to use it [1]. The peak flow meter is small, inexpensive, and easy for most patients to use.
The NAEPP recommend that patients use a peak flow meter to: Provide a regular assessment of lung function and response to treatment over the short- and long-term Determine the severity of an asthma attack Assess response to treatment during an attack
Patients should use an asthma diary to record their daily peak flow meter readings, exposure to potential asthma triggers, asthma medication use, and asthma symptoms (show figure 1). This can help patients to see a cause-and-effect relationship between exposure to triggers and decreases in peak flow. The asthma diary can be reviewed with a healthcare provider to make decisions about asthma treatment. (See "Patient information: Trigger avoidance in asthma" and see "Patient information: Metered dose inhaler techniques").
HOW TO USE A PEAK FLOW METER — PEFR monitoring should be performed on a regular basis, even when asthma symptoms are not present. PEFR should also be checked if symptoms of coughing, wheezing, or shortness of breath develops. Patients should demonstrate PEFR measurement with their healthcare provider to verify that their technique is accurate.
Different brands of peak flow meters have unique features; however, these general instructions can be adapted to an individual's peak flow meter.
Getting the best readings — Several steps are important to make sure the peak flow meter records an accurate value: The peak flow meter should read zero or its lowest reading when not in use Use the peak flow meter while standing up straight Take in as deep a breath as possible Place the peak flow meter in the mouth, with the tongue under the mouthpiece Close the lips tightly around the mouthpiece Blow out as hard and fast as possible Breathe a few normal breaths and then repeat the process two more times. Write down the highest number obtained. Do not average the numbers.
Note: The test should be repeated if the tongue partially blocks the mouthpiece or if the patient coughs or spits during the test. Most peak flow meters need to be cleaned periodically; cleaning instructions should be available when the unit is purchased.
Establishing a baseline measurement — Unlike a blood pressure reading or a cholesterol test, there is no PEFR that is normal for everyone. For this reason, it is important to determine what PEFR value is normal for each individual.
To determine an individual patient's normal PEFR, they should measure their PEFR when they have no asthma symptoms. Three PEFR measurements should be done with the same peak flow meter two to four times daily for two to three weeks. For long term management, most clinicians will recommend testing once per day, usually in the morning.
The patient should note the highest PEFR measure achieved; this is the "personal best" PEFR. This number is used to determine if future PEFR readings are normal or low, and is also used to create a normal PEFR range (between 80 and 100 percent of the personal best PEFR).
Readings below the normal range are a sign of airway narrowing in the lungs. A low PEFR can occur before asthma symptoms such as wheezing or shortness of breath develop.
A personal best PEFR value should be remeasured each year to account for growth (in children) or changes in the disease (in both children and adults). In addition, home PEFR measurements should be verified with readings taken with equipment in a healthcare provider's office since this equipment is more sensitive.
The action plan — Once the normal range can been established, the healthcare provider will provide tailored guidelines (also called an action plan) to follow when the PEFR begins to decrease (show figure 2 and show figure 3).
Peak expiratory flow rates are divided into three zones, which are assigned colors similar to those of a traffic light. These zones can be used to make decisions about the need for treatment: GREEN (80 to 100 percent of personal best) signals that the lungs are functioning well. When readings are within this range and symptoms are not present, patients should continue their regular medicines and activities. YELLOW (50 to 80 percent of personal best) is a sign that the airways in the lungs are somewhat narrowed, making it difficult to move air in and out. A short-term change or increase in medication is generally required. Patients should change or increase their medication to reverse airway narrowing according to the treatment recommendations previously discussed with their provider. RED (below 50 percent of personal best) is a sign that the airways are significantly narrowed and requires immediate treatment. The "rescue" inhaler should be used according to the treatment recommendation previously discussed with the provider. PEFR should be rechecked 10 to 15 minutes after the rescue medication is used. If the PEFR improves, the patient should monitor their PEFR throughout the day. The healthcare provider should be contacted after the patient improves; daily medication may be changed or increased.
EMERGENCY CARE — Patients with asthma who fail to improve or worsen despite treatment require emergency medical services. Severe asthma attacks can be fatal if not treated promptly. In most areas of the United States, 911 can be called for emergency medical assistance. Patients should not attempt to drive to a hospital or clinician's office on their own.
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 Heart, Lung, and Blood Institute
(www.nhlbi.nih.gov/)
National Lung Health Education Program
(www.nlhep.org)
American Lung Association
(www.lungusa.org)
American Academy of Allergy, Asthma, and Immunology
(www.aaaai.org/patients.stm)
American College of Allergy, Asthma, and Immunology
(www.acaai.org/public/)
[1-6]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. National Asthma Education Program Expert Panel. Guidelines for the diagnosis and management of asthma: Update on Selected Topics 2002. US Department of Health and Human Services, National Institutes of Health, Bethesda, (NIH Publication No. 02-5074) June 2003.
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. Ignacio-Garcia, JM, Gonzalez-Santos, P. Asthma self-management education program by home monitoring of peak expiratory flow. Am J Respir Crit Care Med 1995; 151:353.
4. Jones, KP, Mullee, MA, Middleton, M, et al. Peak flow based asthma self-management: a randomised controlled study in general practice. British Thoracic Society Research Committee. Thorax 1995; 50:851.
5. Breathe Well, Live Well: An asthma management program for adults: The American Lung Association 2005.
6. 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.
Tuesday, October 9, 2007
ASTHMA Patient information: How to use a peak flow meter
INTRODUCTION — The management of asthma relies on a patient's ability to monitor their asthma regularly. Self-monitoring includes assessing the frequency and severity of symptoms (such as wheezing and shortness of breath) and measurement of lung function with tests such as a peak expiratory flow rate (PEFR). PEFR provides a number that correlates to how open the lung's airways are; as asthma worsens and the airways narrow, the PEFR decreases. Monitoring can help a patient and their healthcare provider determine the most appropriate asthma treatment plan. (See "Patient information: Overview of managing asthma").
ASTHMA MONITORING RECOMMENDATIONS — The National Asthma Education and Prevention Program (NAEPP) recommends that patients with moderate to severe persistent asthma have a peak flow meter at home and know how to use it [1]. The peak flow meter is small, inexpensive, and easy for most patients to use.
The NAEPP recommend that patients use a peak flow meter to: Provide a regular assessment of lung function and response to treatment over the short- and long-term Determine the severity of an asthma attack Assess response to treatment during an attack
Patients should use an asthma diary to record their daily peak flow meter readings, exposure to potential asthma triggers, asthma medication use, and asthma symptoms (show figure 1). This can help patients to see a cause-and-effect relationship between exposure to triggers and decreases in peak flow. The asthma diary can be reviewed with a healthcare provider to make decisions about asthma treatment. (See "Patient information: Trigger avoidance in asthma" and see "Patient information: Metered dose inhaler techniques").
HOW TO USE A PEAK FLOW METER — PEFR monitoring should be performed on a regular basis, even when asthma symptoms are not present. PEFR should also be checked if symptoms of coughing, wheezing, or shortness of breath develops. Patients should demonstrate PEFR measurement with their healthcare provider to verify that their technique is accurate.
Different brands of peak flow meters have unique features; however, these general instructions can be adapted to an individual's peak flow meter.
Getting the best readings — Several steps are important to make sure the peak flow meter records an accurate value: The peak flow meter should read zero or its lowest reading when not in use Use the peak flow meter while standing up straight Take in as deep a breath as possible Place the peak flow meter in the mouth, with the tongue under the mouthpiece Close the lips tightly around the mouthpiece Blow out as hard and fast as possible Breathe a few normal breaths and then repeat the process two more times. Write down the highest number obtained. Do not average the numbers.
Note: The test should be repeated if the tongue partially blocks the mouthpiece or if the patient coughs or spits during the test. Most peak flow meters need to be cleaned periodically; cleaning instructions should be available when the unit is purchased.
Establishing a baseline measurement — Unlike a blood pressure reading or a cholesterol test, there is no PEFR that is normal for everyone. For this reason, it is important to determine what PEFR value is normal for each individual.
To determine an individual patient's normal PEFR, they should measure their PEFR when they have no asthma symptoms. Three PEFR measurements should be done with the same peak flow meter two to four times daily for two to three weeks. For long term management, most clinicians will recommend testing once per day, usually in the morning.
The patient should note the highest PEFR measure achieved; this is the "personal best" PEFR. This number is used to determine if future PEFR readings are normal or low, and is also used to create a normal PEFR range (between 80 and 100 percent of the personal best PEFR).
Readings below the normal range are a sign of airway narrowing in the lungs. A low PEFR can occur before asthma symptoms such as wheezing or shortness of breath develop.
A personal best PEFR value should be remeasured each year to account for growth (in children) or changes in the disease (in both children and adults). In addition, home PEFR measurements should be verified with readings taken with equipment in a healthcare provider's office since this equipment is more sensitive.
The action plan — Once the normal range can been established, the healthcare provider will provide tailored guidelines (also called an action plan) to follow when the PEFR begins to decrease (show figure 2 and show figure 3).
Peak expiratory flow rates are divided into three zones, which are assigned colors similar to those of a traffic light. These zones can be used to make decisions about the need for treatment: GREEN (80 to 100 percent of personal best) signals that the lungs are functioning well. When readings are within this range and symptoms are not present, patients should continue their regular medicines and activities. YELLOW (50 to 80 percent of personal best) is a sign that the airways in the lungs are somewhat narrowed, making it difficult to move air in and out. A short-term change or increase in medication is generally required. Patients should change or increase their medication to reverse airway narrowing according to the treatment recommendations previously discussed with their provider. RED (below 50 percent of personal best) is a sign that the airways are significantly narrowed and requires immediate treatment. The "rescue" inhaler should be used according to the treatment recommendation previously discussed with the provider. PEFR should be rechecked 10 to 15 minutes after the rescue medication is used. If the PEFR improves, the patient should monitor their PEFR throughout the day. The healthcare provider should be contacted after the patient improves; daily medication may be changed or increased.
EMERGENCY CARE — Patients with asthma who fail to improve or worsen despite treatment require emergency medical services. Severe asthma attacks can be fatal if not treated promptly. In most areas of the United States, 911 can be called for emergency medical assistance. Patients should not attempt to drive to a hospital or clinician's office on their own.
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 Heart, Lung, and Blood Institute
(www.nhlbi.nih.gov/)
National Lung Health Education Program
(www.nlhep.org)
American Lung Association
(www.lungusa.org)
American Academy of Allergy, Asthma, and Immunology
(www.aaaai.org/patients.stm)
American College of Allergy, Asthma, and Immunology
(www.acaai.org/public/)
[1-6]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. National Asthma Education Program Expert Panel. Guidelines for the diagnosis and management of asthma: Update on Selected Topics 2002. US Department of Health and Human Services, National Institutes of Health, Bethesda, (NIH Publication No. 02-5074) June 2003.
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. Ignacio-Garcia, JM, Gonzalez-Santos, P. Asthma self-management education program by home monitoring of peak expiratory flow. Am J Respir Crit Care Med 1995; 151:353.
4. Jones, KP, Mullee, MA, Middleton, M, et al. Peak flow based asthma self-management: a randomised controlled study in general practice. British Thoracic Society Research Committee. Thorax 1995; 50:851.
5. Breathe Well, Live Well: An asthma management program for adults: The American Lung Association 2005.
6. 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.
ASTHMA MONITORING RECOMMENDATIONS — The National Asthma Education and Prevention Program (NAEPP) recommends that patients with moderate to severe persistent asthma have a peak flow meter at home and know how to use it [1]. The peak flow meter is small, inexpensive, and easy for most patients to use.
The NAEPP recommend that patients use a peak flow meter to: Provide a regular assessment of lung function and response to treatment over the short- and long-term Determine the severity of an asthma attack Assess response to treatment during an attack
Patients should use an asthma diary to record their daily peak flow meter readings, exposure to potential asthma triggers, asthma medication use, and asthma symptoms (show figure 1). This can help patients to see a cause-and-effect relationship between exposure to triggers and decreases in peak flow. The asthma diary can be reviewed with a healthcare provider to make decisions about asthma treatment. (See "Patient information: Trigger avoidance in asthma" and see "Patient information: Metered dose inhaler techniques").
HOW TO USE A PEAK FLOW METER — PEFR monitoring should be performed on a regular basis, even when asthma symptoms are not present. PEFR should also be checked if symptoms of coughing, wheezing, or shortness of breath develops. Patients should demonstrate PEFR measurement with their healthcare provider to verify that their technique is accurate.
Different brands of peak flow meters have unique features; however, these general instructions can be adapted to an individual's peak flow meter.
Getting the best readings — Several steps are important to make sure the peak flow meter records an accurate value: The peak flow meter should read zero or its lowest reading when not in use Use the peak flow meter while standing up straight Take in as deep a breath as possible Place the peak flow meter in the mouth, with the tongue under the mouthpiece Close the lips tightly around the mouthpiece Blow out as hard and fast as possible Breathe a few normal breaths and then repeat the process two more times. Write down the highest number obtained. Do not average the numbers.
Note: The test should be repeated if the tongue partially blocks the mouthpiece or if the patient coughs or spits during the test. Most peak flow meters need to be cleaned periodically; cleaning instructions should be available when the unit is purchased.
Establishing a baseline measurement — Unlike a blood pressure reading or a cholesterol test, there is no PEFR that is normal for everyone. For this reason, it is important to determine what PEFR value is normal for each individual.
To determine an individual patient's normal PEFR, they should measure their PEFR when they have no asthma symptoms. Three PEFR measurements should be done with the same peak flow meter two to four times daily for two to three weeks. For long term management, most clinicians will recommend testing once per day, usually in the morning.
The patient should note the highest PEFR measure achieved; this is the "personal best" PEFR. This number is used to determine if future PEFR readings are normal or low, and is also used to create a normal PEFR range (between 80 and 100 percent of the personal best PEFR).
Readings below the normal range are a sign of airway narrowing in the lungs. A low PEFR can occur before asthma symptoms such as wheezing or shortness of breath develop.
A personal best PEFR value should be remeasured each year to account for growth (in children) or changes in the disease (in both children and adults). In addition, home PEFR measurements should be verified with readings taken with equipment in a healthcare provider's office since this equipment is more sensitive.
The action plan — Once the normal range can been established, the healthcare provider will provide tailored guidelines (also called an action plan) to follow when the PEFR begins to decrease (show figure 2 and show figure 3).
Peak expiratory flow rates are divided into three zones, which are assigned colors similar to those of a traffic light. These zones can be used to make decisions about the need for treatment: GREEN (80 to 100 percent of personal best) signals that the lungs are functioning well. When readings are within this range and symptoms are not present, patients should continue their regular medicines and activities. YELLOW (50 to 80 percent of personal best) is a sign that the airways in the lungs are somewhat narrowed, making it difficult to move air in and out. A short-term change or increase in medication is generally required. Patients should change or increase their medication to reverse airway narrowing according to the treatment recommendations previously discussed with their provider. RED (below 50 percent of personal best) is a sign that the airways are significantly narrowed and requires immediate treatment. The "rescue" inhaler should be used according to the treatment recommendation previously discussed with the provider. PEFR should be rechecked 10 to 15 minutes after the rescue medication is used. If the PEFR improves, the patient should monitor their PEFR throughout the day. The healthcare provider should be contacted after the patient improves; daily medication may be changed or increased.
EMERGENCY CARE — Patients with asthma who fail to improve or worsen despite treatment require emergency medical services. Severe asthma attacks can be fatal if not treated promptly. In most areas of the United States, 911 can be called for emergency medical assistance. Patients should not attempt to drive to a hospital or clinician's office on their own.
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 Heart, Lung, and Blood Institute
(www.nhlbi.nih.gov/)
National Lung Health Education Program
(www.nlhep.org)
American Lung Association
(www.lungusa.org)
American Academy of Allergy, Asthma, and Immunology
(www.aaaai.org/patients.stm)
American College of Allergy, Asthma, and Immunology
(www.acaai.org/public/)
[1-6]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. National Asthma Education Program Expert Panel. Guidelines for the diagnosis and management of asthma: Update on Selected Topics 2002. US Department of Health and Human Services, National Institutes of Health, Bethesda, (NIH Publication No. 02-5074) June 2003.
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. Ignacio-Garcia, JM, Gonzalez-Santos, P. Asthma self-management education program by home monitoring of peak expiratory flow. Am J Respir Crit Care Med 1995; 151:353.
4. Jones, KP, Mullee, MA, Middleton, M, et al. Peak flow based asthma self-management: a randomised controlled study in general practice. British Thoracic Society Research Committee. Thorax 1995; 50:851.
5. Breathe Well, Live Well: An asthma management program for adults: The American Lung Association 2005.
6. 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.
ASTHMA Patient information: Use of an epinephrine autoinjector
INTRODUCTION — Allergic reactions can be triggered by foods, medications, exercise, latex, insect stings, or unknown triggers, and can cause a sudden, potentially life-threatening allergic reaction called anaphylaxis. Epinephrine (also known as adrenaline) is a medicine that treats the symptoms of serious allergic reactions. (See "Patient information: Anaphylaxis").
PATIENT AND FAMILY EDUCATION — A person with allergies, as well as his or her family, close friends, teachers, and co-workers, should learn to use an epinephrine autoinjector before it is needed. Persons suffering with anaphylaxis may panic and be unable to assist with their own injection. In addition, a quick response is necessary to prevent serious complications of anaphylaxis.
Patients should fill their epinephrine autoinjector prescription immediately, and should keep at least one epinephrine autoinjector with them at all times. It is a good idea to have an additional autoinjector at work, school, and home. Family and friends should be informed about where the home injector is stored, and it should be kept in a place that can be easily located by others in an emergency. It is also important to ensure that the injector is not expired, although an expired injector may be used if there is no alternative.
Epinephrine should be stored at normal room temperature, away from cold and heat sources. The epinephrine cartridge window should be examined periodically, to ensure that the solution is colorless and contains no floating particles. Solutions that are discolored or contain particles should be replaced.
SYMPTOMS OF ALLERGY — Allergic reaction can produce symptoms throughout the body. Skin: A sudden tingling and warm sensation, itching, flushing, urticaria (hives), and angioedema (swelling). Eyes: Itching, tearing, and swelling of the tissues around the eyes. Nose and mouth: Sneezing, runny nose, nasal congestion, itching of the mouth, and a metallic taste. Lungs and throat: Difficulty breathing, coughing, wheezing, increased airway secretions, swelling of the upper throat, hoarseness, sounds of labored breathing, and a sensation of choking. Heart: Very rapid heartbeat, arrhythmia (an irregular heart beat), low blood pressure, and cardiac arrest (a cessation of the heart's pumping action). Digestive system: Nausea, vomiting, abdominal cramps, bloating, and diarrhea. Nervous system: Dizziness, weakness, fainting, and a sense of impending doom.
WHEN TO TREAT — Persons having an allergic reaction should use their epinephrine autoinjector immediately if they: Are having trouble breathing Feel tightness in the throat Feel they might pass out
If treating a child with an allergic reaction, also use the autoinjector if the child: Is not responding or seems groggy during an allergic reaction Has food allergies and is vomiting repeatedly shortly after eating, especially if these symptoms are accompanied by flushing or hives
HOW TO TREAT — Patients should read the instructions provided with their autoinjector, and should review them each time a refill is obtained in case changes have been made. Instructions may differ from one autoinjector to another.
Epipen® or Epipen Jr.®
Sit down or lie down if possible. Stay with other people if possible. There is no need to undress, as the injector works through clothing.
1. Unscrew the cap and remove the pen from its case (show picture 1). Keep fingers away from both ends to avoid sticking them. The black end contains the needle.
2. Pull off the gray safety-release cap and form a fist around the auto-injector. The black tip should be pointing down.
3. Swing and quickly jab the black tip into the upper, outer thigh muscle and hold in place for 10 seconds to allow all the medicine to be injected (show figure 1). The cartridge window will show red.
4. Remove the pen.
5. Massage the injected area for 10 seconds.
6. Call 911 and get to the nearest emergency department immediately (patients should not drive themselves). Allergic reactions sometimes come back.
7. Replace the pen in the case, and take it to the hospital.
The Epipen® is now availabe in packages of two, in case a second dose is needed. Large-sized adults may need to repeat the dose. A second dose may also be needed if symptoms are not improving or getting worse after five minutes, or if symptoms come back before reaching the emergency department.
Twinject®
Sit down or lie down if possible. Stay with other people if possible. There is no need to undress, as the injector works through clothing.
1. Remove the pen from its grey case, keeping your fingers off both ends to avoid sticking your finger (show picture 2).
2. Pull off the green cap, labeled "1". This will reveal a grey tip, which contains a needle inside.
3. Pull off the red cap, labeled "2".
4. Form a fist around the autoinjector with the grey tip pointing down.
5. Place the grey tip against the upper, outer thigh, and press firmly until the needle enters the skin. Hold in place for 10 seconds to allow all the medicine to be injected (show figure 1).
6. Remove the injector and check the grey cap. If the needle is visible, epinephrine was given. If the needle is not present, repeat steps 4 through 5 again.
7. Massage the injected area for 10 seconds.
8. Call 911 and get to the nearest emergency department immediately (Patients should not drive themselves). Allergic reactions sometimes come back.
9. Take the pen to the hospital.
The Twinject® contains a second dose inside the cartridge. Large-sized adults may need to repeat the dose. A second dose may be needed if symptoms are not improving or getting worse after five minutes, or if symptoms come back before reaching the emergency department. Studies have shown that one in three patients will need a second dose.
To remove the inside injector: Unscrew the grey cap, taking care to avoid the needle. Hold the blue ring and pull the small injector out.
To use the second dose: Slide the yellow or orange collar off plunger at the other end. Quickly jab the injector firmly into your thigh muscle; push the plunger all the way down to inject the medicine. Remove the injector.
Injector disposal — Injectors should not be thrown away with household trash since they contain a needle. Patients should take their used injectors to a hospital or healthcare provider for proper disposal.
SIDE EFFECTS — The benefits of epinephrine in treatment of a severe allergic reaction far outweigh the risks of side effects. However, epinephrine can cause short-lived side effects in some patients. The most common side effects include the following:
Heart — Fast and/or pounding heartbeat, fleeting chest pain
Nervous system — Nervousness, trembling, feeling cold, anxiety, headache, dizziness
Digestive system — Nausea, dry throat
Lungs — Fleeting shortness of breath
FOLLOW-UP CARE — Patients can have varying responses to a severe allergic reaction. Some patients have symptoms that will resolve rapidly and completely with treatment. These patients may feel fatigued, but otherwise normal afterwards. Other patients have symptoms that take longer to resolve. For most patients, facial swelling and asthma symptoms resolve completely after 24 to 48 hours.
Some patients experience a second reaction after the initial allergic reaction, although this is not common. Second reactions can occur hours to up to four days later, although most second reactions happen within eight hours.
In most cases, the doctor may advise taking antihistamines regularly for several days after the allergic reaction. Oral corticosteroids, a type of medication that reduces inflammation, may also be prescribed. Antihistamines and corticosteroids are prescribed to treat residual symptoms; it is also possible (but not proven) that these medications can help to prevent a second reaction.
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 Food Allergy and Anaphylaxis Network
(www.foodallergy.org)
American Academy of Allergy, Asthma, and Immunology
(www.aaaai.org)
Anaphylaxis Foundation and Anaphylaxis Network of Canada
(www.anaphylaxis.org)
The Anaphylaxis Campaign
(www.anaphylaxis.org.uk)
[1-7]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Bochner, BS, Lichtenstein, LM. Anaphylaxis. N Engl J Med 1991; 324:1785.
2. Ewan, PW. Anaphylaxis. BMJ 1998; 316:1442.
3. Fisher, M. Treatment of acute anaphylaxis. BMJ 1995; 311:731.
4. Kemp, SF, Lockey, RF, Wolf, BL, Lieberman, P. Anaphylaxis: Review of 266 cases. Arch Intern Med 1995; 155:1749.
5. Chamberlain, D. Emergency medical treatment of anaphylactic reactions. Project Team of the Resuscitation Council (UK). J Accid Emerg Med 1999; 16:243.
6. Golden, DB. Patterns of anaphylaxis: acute and late phase features of allergic reactions. Novartis Found Symp 2004; 257:101.
7. Pumphrey, R. Anaphylaxis: can we tell who is at risk of a fatal reaction?. Curr Opin Allergy Clin Immunol 2004; 4:285.
PATIENT AND FAMILY EDUCATION — A person with allergies, as well as his or her family, close friends, teachers, and co-workers, should learn to use an epinephrine autoinjector before it is needed. Persons suffering with anaphylaxis may panic and be unable to assist with their own injection. In addition, a quick response is necessary to prevent serious complications of anaphylaxis.
Patients should fill their epinephrine autoinjector prescription immediately, and should keep at least one epinephrine autoinjector with them at all times. It is a good idea to have an additional autoinjector at work, school, and home. Family and friends should be informed about where the home injector is stored, and it should be kept in a place that can be easily located by others in an emergency. It is also important to ensure that the injector is not expired, although an expired injector may be used if there is no alternative.
Epinephrine should be stored at normal room temperature, away from cold and heat sources. The epinephrine cartridge window should be examined periodically, to ensure that the solution is colorless and contains no floating particles. Solutions that are discolored or contain particles should be replaced.
SYMPTOMS OF ALLERGY — Allergic reaction can produce symptoms throughout the body. Skin: A sudden tingling and warm sensation, itching, flushing, urticaria (hives), and angioedema (swelling). Eyes: Itching, tearing, and swelling of the tissues around the eyes. Nose and mouth: Sneezing, runny nose, nasal congestion, itching of the mouth, and a metallic taste. Lungs and throat: Difficulty breathing, coughing, wheezing, increased airway secretions, swelling of the upper throat, hoarseness, sounds of labored breathing, and a sensation of choking. Heart: Very rapid heartbeat, arrhythmia (an irregular heart beat), low blood pressure, and cardiac arrest (a cessation of the heart's pumping action). Digestive system: Nausea, vomiting, abdominal cramps, bloating, and diarrhea. Nervous system: Dizziness, weakness, fainting, and a sense of impending doom.
WHEN TO TREAT — Persons having an allergic reaction should use their epinephrine autoinjector immediately if they: Are having trouble breathing Feel tightness in the throat Feel they might pass out
If treating a child with an allergic reaction, also use the autoinjector if the child: Is not responding or seems groggy during an allergic reaction Has food allergies and is vomiting repeatedly shortly after eating, especially if these symptoms are accompanied by flushing or hives
HOW TO TREAT — Patients should read the instructions provided with their autoinjector, and should review them each time a refill is obtained in case changes have been made. Instructions may differ from one autoinjector to another.
Epipen® or Epipen Jr.®
Sit down or lie down if possible. Stay with other people if possible. There is no need to undress, as the injector works through clothing.
1. Unscrew the cap and remove the pen from its case (show picture 1). Keep fingers away from both ends to avoid sticking them. The black end contains the needle.
2. Pull off the gray safety-release cap and form a fist around the auto-injector. The black tip should be pointing down.
3. Swing and quickly jab the black tip into the upper, outer thigh muscle and hold in place for 10 seconds to allow all the medicine to be injected (show figure 1). The cartridge window will show red.
4. Remove the pen.
5. Massage the injected area for 10 seconds.
6. Call 911 and get to the nearest emergency department immediately (patients should not drive themselves). Allergic reactions sometimes come back.
7. Replace the pen in the case, and take it to the hospital.
The Epipen® is now availabe in packages of two, in case a second dose is needed. Large-sized adults may need to repeat the dose. A second dose may also be needed if symptoms are not improving or getting worse after five minutes, or if symptoms come back before reaching the emergency department.
Twinject®
Sit down or lie down if possible. Stay with other people if possible. There is no need to undress, as the injector works through clothing.
1. Remove the pen from its grey case, keeping your fingers off both ends to avoid sticking your finger (show picture 2).
2. Pull off the green cap, labeled "1". This will reveal a grey tip, which contains a needle inside.
3. Pull off the red cap, labeled "2".
4. Form a fist around the autoinjector with the grey tip pointing down.
5. Place the grey tip against the upper, outer thigh, and press firmly until the needle enters the skin. Hold in place for 10 seconds to allow all the medicine to be injected (show figure 1).
6. Remove the injector and check the grey cap. If the needle is visible, epinephrine was given. If the needle is not present, repeat steps 4 through 5 again.
7. Massage the injected area for 10 seconds.
8. Call 911 and get to the nearest emergency department immediately (Patients should not drive themselves). Allergic reactions sometimes come back.
9. Take the pen to the hospital.
The Twinject® contains a second dose inside the cartridge. Large-sized adults may need to repeat the dose. A second dose may be needed if symptoms are not improving or getting worse after five minutes, or if symptoms come back before reaching the emergency department. Studies have shown that one in three patients will need a second dose.
To remove the inside injector: Unscrew the grey cap, taking care to avoid the needle. Hold the blue ring and pull the small injector out.
To use the second dose: Slide the yellow or orange collar off plunger at the other end. Quickly jab the injector firmly into your thigh muscle; push the plunger all the way down to inject the medicine. Remove the injector.
Injector disposal — Injectors should not be thrown away with household trash since they contain a needle. Patients should take their used injectors to a hospital or healthcare provider for proper disposal.
SIDE EFFECTS — The benefits of epinephrine in treatment of a severe allergic reaction far outweigh the risks of side effects. However, epinephrine can cause short-lived side effects in some patients. The most common side effects include the following:
Heart — Fast and/or pounding heartbeat, fleeting chest pain
Nervous system — Nervousness, trembling, feeling cold, anxiety, headache, dizziness
Digestive system — Nausea, dry throat
Lungs — Fleeting shortness of breath
FOLLOW-UP CARE — Patients can have varying responses to a severe allergic reaction. Some patients have symptoms that will resolve rapidly and completely with treatment. These patients may feel fatigued, but otherwise normal afterwards. Other patients have symptoms that take longer to resolve. For most patients, facial swelling and asthma symptoms resolve completely after 24 to 48 hours.
Some patients experience a second reaction after the initial allergic reaction, although this is not common. Second reactions can occur hours to up to four days later, although most second reactions happen within eight hours.
In most cases, the doctor may advise taking antihistamines regularly for several days after the allergic reaction. Oral corticosteroids, a type of medication that reduces inflammation, may also be prescribed. Antihistamines and corticosteroids are prescribed to treat residual symptoms; it is also possible (but not proven) that these medications can help to prevent a second reaction.
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 Food Allergy and Anaphylaxis Network
(www.foodallergy.org)
American Academy of Allergy, Asthma, and Immunology
(www.aaaai.org)
Anaphylaxis Foundation and Anaphylaxis Network of Canada
(www.anaphylaxis.org)
The Anaphylaxis Campaign
(www.anaphylaxis.org.uk)
[1-7]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Bochner, BS, Lichtenstein, LM. Anaphylaxis. N Engl J Med 1991; 324:1785.
2. Ewan, PW. Anaphylaxis. BMJ 1998; 316:1442.
3. Fisher, M. Treatment of acute anaphylaxis. BMJ 1995; 311:731.
4. Kemp, SF, Lockey, RF, Wolf, BL, Lieberman, P. Anaphylaxis: Review of 266 cases. Arch Intern Med 1995; 155:1749.
5. Chamberlain, D. Emergency medical treatment of anaphylactic reactions. Project Team of the Resuscitation Council (UK). J Accid Emerg Med 1999; 16:243.
6. Golden, DB. Patterns of anaphylaxis: acute and late phase features of allergic reactions. Novartis Found Symp 2004; 257:101.
7. Pumphrey, R. Anaphylaxis: can we tell who is at risk of a fatal reaction?. Curr Opin Allergy Clin Immunol 2004; 4:285.
ASTHMA Patient information: Use of an epinephrine autoinjector
INTRODUCTION — Allergic reactions can be triggered by foods, medications, exercise, latex, insect stings, or unknown triggers, and can cause a sudden, potentially life-threatening allergic reaction called anaphylaxis. Epinephrine (also known as adrenaline) is a medicine that treats the symptoms of serious allergic reactions. (See "Patient information: Anaphylaxis").
PATIENT AND FAMILY EDUCATION — A person with allergies, as well as his or her family, close friends, teachers, and co-workers, should learn to use an epinephrine autoinjector before it is needed. Persons suffering with anaphylaxis may panic and be unable to assist with their own injection. In addition, a quick response is necessary to prevent serious complications of anaphylaxis.
Patients should fill their epinephrine autoinjector prescription immediately, and should keep at least one epinephrine autoinjector with them at all times. It is a good idea to have an additional autoinjector at work, school, and home. Family and friends should be informed about where the home injector is stored, and it should be kept in a place that can be easily located by others in an emergency. It is also important to ensure that the injector is not expired, although an expired injector may be used if there is no alternative.
Epinephrine should be stored at normal room temperature, away from cold and heat sources. The epinephrine cartridge window should be examined periodically, to ensure that the solution is colorless and contains no floating particles. Solutions that are discolored or contain particles should be replaced.
SYMPTOMS OF ALLERGY — Allergic reaction can produce symptoms throughout the body. Skin: A sudden tingling and warm sensation, itching, flushing, urticaria (hives), and angioedema (swelling). Eyes: Itching, tearing, and swelling of the tissues around the eyes. Nose and mouth: Sneezing, runny nose, nasal congestion, itching of the mouth, and a metallic taste. Lungs and throat: Difficulty breathing, coughing, wheezing, increased airway secretions, swelling of the upper throat, hoarseness, sounds of labored breathing, and a sensation of choking. Heart: Very rapid heartbeat, arrhythmia (an irregular heart beat), low blood pressure, and cardiac arrest (a cessation of the heart's pumping action). Digestive system: Nausea, vomiting, abdominal cramps, bloating, and diarrhea. Nervous system: Dizziness, weakness, fainting, and a sense of impending doom.
WHEN TO TREAT — Persons having an allergic reaction should use their epinephrine autoinjector immediately if they: Are having trouble breathing Feel tightness in the throat Feel they might pass out
If treating a child with an allergic reaction, also use the autoinjector if the child: Is not responding or seems groggy during an allergic reaction Has food allergies and is vomiting repeatedly shortly after eating, especially if these symptoms are accompanied by flushing or hives
HOW TO TREAT — Patients should read the instructions provided with their autoinjector, and should review them each time a refill is obtained in case changes have been made. Instructions may differ from one autoinjector to another.
Epipen® or Epipen Jr.®
Sit down or lie down if possible. Stay with other people if possible. There is no need to undress, as the injector works through clothing.
1. Unscrew the cap and remove the pen from its case (show picture 1). Keep fingers away from both ends to avoid sticking them. The black end contains the needle.
2. Pull off the gray safety-release cap and form a fist around the auto-injector. The black tip should be pointing down.
3. Swing and quickly jab the black tip into the upper, outer thigh muscle and hold in place for 10 seconds to allow all the medicine to be injected (show figure 1). The cartridge window will show red.
4. Remove the pen.
5. Massage the injected area for 10 seconds.
6. Call 911 and get to the nearest emergency department immediately (patients should not drive themselves). Allergic reactions sometimes come back.
7. Replace the pen in the case, and take it to the hospital.
The Epipen® is now availabe in packages of two, in case a second dose is needed. Large-sized adults may need to repeat the dose. A second dose may also be needed if symptoms are not improving or getting worse after five minutes, or if symptoms come back before reaching the emergency department.
Twinject®
Sit down or lie down if possible. Stay with other people if possible. There is no need to undress, as the injector works through clothing.
1. Remove the pen from its grey case, keeping your fingers off both ends to avoid sticking your finger (show picture 2).
2. Pull off the green cap, labeled "1". This will reveal a grey tip, which contains a needle inside.
3. Pull off the red cap, labeled "2".
4. Form a fist around the autoinjector with the grey tip pointing down.
5. Place the grey tip against the upper, outer thigh, and press firmly until the needle enters the skin. Hold in place for 10 seconds to allow all the medicine to be injected (show figure 1).
6. Remove the injector and check the grey cap. If the needle is visible, epinephrine was given. If the needle is not present, repeat steps 4 through 5 again.
7. Massage the injected area for 10 seconds.
8. Call 911 and get to the nearest emergency department immediately (Patients should not drive themselves). Allergic reactions sometimes come back.
9. Take the pen to the hospital.
The Twinject® contains a second dose inside the cartridge. Large-sized adults may need to repeat the dose. A second dose may be needed if symptoms are not improving or getting worse after five minutes, or if symptoms come back before reaching the emergency department. Studies have shown that one in three patients will need a second dose.
To remove the inside injector: Unscrew the grey cap, taking care to avoid the needle. Hold the blue ring and pull the small injector out.
To use the second dose: Slide the yellow or orange collar off plunger at the other end. Quickly jab the injector firmly into your thigh muscle; push the plunger all the way down to inject the medicine. Remove the injector.
Injector disposal — Injectors should not be thrown away with household trash since they contain a needle. Patients should take their used injectors to a hospital or healthcare provider for proper disposal.
SIDE EFFECTS — The benefits of epinephrine in treatment of a severe allergic reaction far outweigh the risks of side effects. However, epinephrine can cause short-lived side effects in some patients. The most common side effects include the following:
Heart — Fast and/or pounding heartbeat, fleeting chest pain
Nervous system — Nervousness, trembling, feeling cold, anxiety, headache, dizziness
Digestive system — Nausea, dry throat
Lungs — Fleeting shortness of breath
FOLLOW-UP CARE — Patients can have varying responses to a severe allergic reaction. Some patients have symptoms that will resolve rapidly and completely with treatment. These patients may feel fatigued, but otherwise normal afterwards. Other patients have symptoms that take longer to resolve. For most patients, facial swelling and asthma symptoms resolve completely after 24 to 48 hours.
Some patients experience a second reaction after the initial allergic reaction, although this is not common. Second reactions can occur hours to up to four days later, although most second reactions happen within eight hours.
In most cases, the doctor may advise taking antihistamines regularly for several days after the allergic reaction. Oral corticosteroids, a type of medication that reduces inflammation, may also be prescribed. Antihistamines and corticosteroids are prescribed to treat residual symptoms; it is also possible (but not proven) that these medications can help to prevent a second reaction.
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 Food Allergy and Anaphylaxis Network
(www.foodallergy.org)
American Academy of Allergy, Asthma, and Immunology
(www.aaaai.org)
Anaphylaxis Foundation and Anaphylaxis Network of Canada
(www.anaphylaxis.org)
The Anaphylaxis Campaign
(www.anaphylaxis.org.uk)
[1-7]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Bochner, BS, Lichtenstein, LM. Anaphylaxis. N Engl J Med 1991; 324:1785.
2. Ewan, PW. Anaphylaxis. BMJ 1998; 316:1442.
3. Fisher, M. Treatment of acute anaphylaxis. BMJ 1995; 311:731.
4. Kemp, SF, Lockey, RF, Wolf, BL, Lieberman, P. Anaphylaxis: Review of 266 cases. Arch Intern Med 1995; 155:1749.
5. Chamberlain, D. Emergency medical treatment of anaphylactic reactions. Project Team of the Resuscitation Council (UK). J Accid Emerg Med 1999; 16:243.
6. Golden, DB. Patterns of anaphylaxis: acute and late phase features of allergic reactions. Novartis Found Symp 2004; 257:101.
7. Pumphrey, R. Anaphylaxis: can we tell who is at risk of a fatal reaction?. Curr Opin Allergy Clin Immunol 2004; 4:285.
PATIENT AND FAMILY EDUCATION — A person with allergies, as well as his or her family, close friends, teachers, and co-workers, should learn to use an epinephrine autoinjector before it is needed. Persons suffering with anaphylaxis may panic and be unable to assist with their own injection. In addition, a quick response is necessary to prevent serious complications of anaphylaxis.
Patients should fill their epinephrine autoinjector prescription immediately, and should keep at least one epinephrine autoinjector with them at all times. It is a good idea to have an additional autoinjector at work, school, and home. Family and friends should be informed about where the home injector is stored, and it should be kept in a place that can be easily located by others in an emergency. It is also important to ensure that the injector is not expired, although an expired injector may be used if there is no alternative.
Epinephrine should be stored at normal room temperature, away from cold and heat sources. The epinephrine cartridge window should be examined periodically, to ensure that the solution is colorless and contains no floating particles. Solutions that are discolored or contain particles should be replaced.
SYMPTOMS OF ALLERGY — Allergic reaction can produce symptoms throughout the body. Skin: A sudden tingling and warm sensation, itching, flushing, urticaria (hives), and angioedema (swelling). Eyes: Itching, tearing, and swelling of the tissues around the eyes. Nose and mouth: Sneezing, runny nose, nasal congestion, itching of the mouth, and a metallic taste. Lungs and throat: Difficulty breathing, coughing, wheezing, increased airway secretions, swelling of the upper throat, hoarseness, sounds of labored breathing, and a sensation of choking. Heart: Very rapid heartbeat, arrhythmia (an irregular heart beat), low blood pressure, and cardiac arrest (a cessation of the heart's pumping action). Digestive system: Nausea, vomiting, abdominal cramps, bloating, and diarrhea. Nervous system: Dizziness, weakness, fainting, and a sense of impending doom.
WHEN TO TREAT — Persons having an allergic reaction should use their epinephrine autoinjector immediately if they: Are having trouble breathing Feel tightness in the throat Feel they might pass out
If treating a child with an allergic reaction, also use the autoinjector if the child: Is not responding or seems groggy during an allergic reaction Has food allergies and is vomiting repeatedly shortly after eating, especially if these symptoms are accompanied by flushing or hives
HOW TO TREAT — Patients should read the instructions provided with their autoinjector, and should review them each time a refill is obtained in case changes have been made. Instructions may differ from one autoinjector to another.
Epipen® or Epipen Jr.®
Sit down or lie down if possible. Stay with other people if possible. There is no need to undress, as the injector works through clothing.
1. Unscrew the cap and remove the pen from its case (show picture 1). Keep fingers away from both ends to avoid sticking them. The black end contains the needle.
2. Pull off the gray safety-release cap and form a fist around the auto-injector. The black tip should be pointing down.
3. Swing and quickly jab the black tip into the upper, outer thigh muscle and hold in place for 10 seconds to allow all the medicine to be injected (show figure 1). The cartridge window will show red.
4. Remove the pen.
5. Massage the injected area for 10 seconds.
6. Call 911 and get to the nearest emergency department immediately (patients should not drive themselves). Allergic reactions sometimes come back.
7. Replace the pen in the case, and take it to the hospital.
The Epipen® is now availabe in packages of two, in case a second dose is needed. Large-sized adults may need to repeat the dose. A second dose may also be needed if symptoms are not improving or getting worse after five minutes, or if symptoms come back before reaching the emergency department.
Twinject®
Sit down or lie down if possible. Stay with other people if possible. There is no need to undress, as the injector works through clothing.
1. Remove the pen from its grey case, keeping your fingers off both ends to avoid sticking your finger (show picture 2).
2. Pull off the green cap, labeled "1". This will reveal a grey tip, which contains a needle inside.
3. Pull off the red cap, labeled "2".
4. Form a fist around the autoinjector with the grey tip pointing down.
5. Place the grey tip against the upper, outer thigh, and press firmly until the needle enters the skin. Hold in place for 10 seconds to allow all the medicine to be injected (show figure 1).
6. Remove the injector and check the grey cap. If the needle is visible, epinephrine was given. If the needle is not present, repeat steps 4 through 5 again.
7. Massage the injected area for 10 seconds.
8. Call 911 and get to the nearest emergency department immediately (Patients should not drive themselves). Allergic reactions sometimes come back.
9. Take the pen to the hospital.
The Twinject® contains a second dose inside the cartridge. Large-sized adults may need to repeat the dose. A second dose may be needed if symptoms are not improving or getting worse after five minutes, or if symptoms come back before reaching the emergency department. Studies have shown that one in three patients will need a second dose.
To remove the inside injector: Unscrew the grey cap, taking care to avoid the needle. Hold the blue ring and pull the small injector out.
To use the second dose: Slide the yellow or orange collar off plunger at the other end. Quickly jab the injector firmly into your thigh muscle; push the plunger all the way down to inject the medicine. Remove the injector.
Injector disposal — Injectors should not be thrown away with household trash since they contain a needle. Patients should take their used injectors to a hospital or healthcare provider for proper disposal.
SIDE EFFECTS — The benefits of epinephrine in treatment of a severe allergic reaction far outweigh the risks of side effects. However, epinephrine can cause short-lived side effects in some patients. The most common side effects include the following:
Heart — Fast and/or pounding heartbeat, fleeting chest pain
Nervous system — Nervousness, trembling, feeling cold, anxiety, headache, dizziness
Digestive system — Nausea, dry throat
Lungs — Fleeting shortness of breath
FOLLOW-UP CARE — Patients can have varying responses to a severe allergic reaction. Some patients have symptoms that will resolve rapidly and completely with treatment. These patients may feel fatigued, but otherwise normal afterwards. Other patients have symptoms that take longer to resolve. For most patients, facial swelling and asthma symptoms resolve completely after 24 to 48 hours.
Some patients experience a second reaction after the initial allergic reaction, although this is not common. Second reactions can occur hours to up to four days later, although most second reactions happen within eight hours.
In most cases, the doctor may advise taking antihistamines regularly for several days after the allergic reaction. Oral corticosteroids, a type of medication that reduces inflammation, may also be prescribed. Antihistamines and corticosteroids are prescribed to treat residual symptoms; it is also possible (but not proven) that these medications can help to prevent a second reaction.
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 Food Allergy and Anaphylaxis Network
(www.foodallergy.org)
American Academy of Allergy, Asthma, and Immunology
(www.aaaai.org)
Anaphylaxis Foundation and Anaphylaxis Network of Canada
(www.anaphylaxis.org)
The Anaphylaxis Campaign
(www.anaphylaxis.org.uk)
[1-7]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Bochner, BS, Lichtenstein, LM. Anaphylaxis. N Engl J Med 1991; 324:1785.
2. Ewan, PW. Anaphylaxis. BMJ 1998; 316:1442.
3. Fisher, M. Treatment of acute anaphylaxis. BMJ 1995; 311:731.
4. Kemp, SF, Lockey, RF, Wolf, BL, Lieberman, P. Anaphylaxis: Review of 266 cases. Arch Intern Med 1995; 155:1749.
5. Chamberlain, D. Emergency medical treatment of anaphylactic reactions. Project Team of the Resuscitation Council (UK). J Accid Emerg Med 1999; 16:243.
6. Golden, DB. Patterns of anaphylaxis: acute and late phase features of allergic reactions. Novartis Found Symp 2004; 257:101.
7. Pumphrey, R. Anaphylaxis: can we tell who is at risk of a fatal reaction?. Curr Opin Allergy Clin Immunol 2004; 4:285.
ASTHMA Patient information: Anaphylaxis
INTRODUCTION — Anaphylaxis is a sudden, potentially life-threatening allergic reaction. Allergic reactions can be triggered by foods, medications, exercise, latex, or insect stings, or unknown triggers.
Every year, about 500 to 1000 people die from severe anaphylaxis. However, many more people likely experience mild or moderate anaphylaxis and do not seek medical care. As a result, the true frequency of anaphylaxis is unknown.
The severity of anaphylactic reactions can be minimized by recognizing the symptoms early, having the proper medications available for self-treatment, and seeking emergency medical care promptly. It is also important to try to identify the specific trigger for each person, although this is not always possible.
PHYSIOLOGY — Anaphylaxis occurs when a trigger activates immune cells, which then release large amounts of multiple substances, including histamine, into the blood stream. This sets off a number of reactions, including itching, dilated blood vessels (leading to low blood pressure and rapid heart rate), mucus secretion, stimulation of the nervous system, and activation of other cells of the immune system. These reactions cause the symptoms that are commonly associated with anaphylaxis.
In some people with anaphylaxis, abnormal antibodies called IgE (proteins that normally fight infections and protect the body) are made in response to non-harmful things, like food or medicines. These IgE antibodies can trigger a violent immune response when the person is later exposed to that food or medicine. The immune response is so strong and uncontrolled that the reaction itself can be harmful. In other people with anaphylaxis, these abnormal IgE proteins are not found, and the reaction is thought to have been caused by other processes.
SYMPTOMS — Symptoms of anaphylaxis generally begin within 5 to 60 minutes of exposure to a trigger. Some patients may not develop symptoms for several hours.
Anaphylaxis can produce symptoms throughout the body: Skin: Itching, flushing, urticaria (hives), and angioedema (swelling). Eyes: Itching, tearing, and swelling of the tissues around the eyes. Nose and mouth: Sneezing, runny nose, nasal congestion, itching of the mouth, and a metallic taste. Lungs and throat: Difficulty breathing, wheezing, increased airway secretions, swelling of the upper throat and/or tongue, hoarseness, sounds of labored breathing, and a sensation of choking. Heart: Very rapid heartbeat, arrhythmia (an irregular heart beat), low blood pressure, and cardiac arrest (a cessation of the heart's pumping action). Digestive system: Nausea, vomiting, abdominal cramps, bloating, and diarrhea. Nervous system: Dizziness, weakness, fainting, and a sense of impending doom.
The most common symptoms of anaphylaxis are urticaria (hives) and angioedema (swelling of the tissues under the skin), which occur in nearly 90 percent of people who have anaphylaxis. These symptoms usually begin after a period of generalized itching, flushing, and sometimes a growing sense of impending doom.
Respiratory symptoms occur in about 50 percent of people who have anaphylaxis and are especially common in people who also have asthma. Gastrointestinal symptoms occur in 30 percent of people. Anaphylactic shock (extremely low blood pressure) occurs in 30 percent of people who have a reaction. Low blood pressure can cause lightheadedness, dizziness, tunnel vision, and loss of consciousness (passing out). These are serious symptoms.
Less commonly, a person may have biphasic or protracted anaphylaxis. A patient with biphasic anaphylaxis has a reaction that resolves but recurs one to eight hours later; second reactions have occurred as much as 72 hours later. A patient with protracted anaphylaxis has signs and symptoms that persist for up to 48 hours despite treatment.
CAUSES — Anaphylaxis triggers can include: Foods, especially seafood, milk, peanuts and tree nuts Drugs, especially certain antibiotics (such as penicillin), nonsteroidal anti-inflammatory drugs (such as aspirin or ibuprofen), drugs used for chemotherapy, and angiotensin-converting enzyme (ACE) inhibitors (See "Patient information: Allergy to penicillin and other antibiotics") Venom from insects, including bees, wasps, kissing bugs, and fire ants Some substances used during x-ray procedures (radiocontrast media) Transfused blood and blood products Exercise or exertion Latex from natural rubber, used to make gloves, balloons, and some medical products
In some cases, a thorough evaluation by an allergy specialist will not identify any specific trigger. This condition is called idiopathic anaphylaxis and is more common in adults than in children.
Food allergies in children — Anaphylaxis in children often results from food allergies. Food allergies are most likely to develop in the first three years of life, when many foods are introduced into a child's diet. Allergies to hen's egg, peanuts, cow's milk, soy, fish, and wheat are among the most common food allergies that children develop. In children over the age of three years, peanuts are the most common allergen. Children often outgrow allergies to milk, eggs, and soybeans. However, allergies to peanuts, other tree nuts, fish and seafood tend to persist.
RISK FACTORS — Several factors help to predict which individuals are most likely to experience anaphylaxis and which factors are most likely to trigger anaphylaxis in specific groups of people.
Age — Children are more likely than adults to have anaphylactic reactions to foods. Adults are more likely to have anaphylactic reactions to antibiotics, radiocontrast media, insect stings, anesthetic drugs, and certain intravenous medicines. They are also more likely to have idiopathic anaphylaxis.
Gender — Overall, women are somewhat more likely to experience anaphylaxis.
Asthma — People with asthma are more likely to experience anaphylaxis and to have more severe respiratory problems during anaphylaxis. The combination of food allergy (especially to peanuts and tree nuts) and asthma seems to put people at risk for particularly dangerous attacks of anaphylaxis.
History of anaphylaxis — People who have had an anaphylactic reaction in the past are at increased risk of future anaphylactic reactions. For example, people who have had an anaphylactic reaction to certain antibiotics are four to six times more likely to have another reaction to these antibiotics when compared to the general population. Similarly, 60 percent of people who have had an allergic reaction to a bee or wasp sting have a severe reaction if stung again, and up to 40 percent of people who have had a reaction to radiocontrast media have a repeat reaction if they are given it again (unless they are given medications to prevent a reaction).
Multiple exposures — People who are exposed to several different allergic stimuli at the same time have an increased risk of anaphylaxis. For example, people who receive immunotherapy (regular injections, also called allergy shots) to decrease a their sensitivity to allergens are more likely to have a severe reaction to their injections during the season(s) when natural exposure is greatest (eg, allergy season, usually spring and fall in most regions of the United States).
DIAGNOSIS — The diagnosis of anaphylaxis is usually based upon the presence of characteristics symptoms, particularly if there is an accompanying story of exposure to a potential trigger, such as a new medicine or insect sting.
However, other problems, such as food poisoning, a severe asthma attack, or cardiac events, can sometimes look like anaphylaxis. In such cases, further evaluation by allergists or other specialists may be needed to clarify the diagnosis. In some cases, the diagnosis of anaphylaxis is difficult to establish.
TREATMENT — A patient who has had an anaphylactic reaction should talk with their healthcare provider to design a plan for responding to future reactions. A plan can minimize the severity of an anaphylactic reaction and ensure that the best treatments are given. Many people find that developing a plan is reassuring, even if it is never needed.
Because anaphylaxis can be life-threatening, it should be treated as an emergency. Most people with moderate to severe anaphylaxis are hospitalized for observation, even when emergency treatment brings the symptoms under control. This hospitalization enables prompt treatment if the symptoms reappear several hours later.
Self-treatment — Patients with allergies or who have a history of anaphylaxis should always carry two epinephrine autoinjectors. A full description of epinephrine autoinjectors is available separately. (See "Patient information: Use of an epinephrine autoinjector").
Remove the cause — The trigger for the anaphylactic reaction should be promptly removed, whenever possible. This removal may entail stopping a drug, or in the case of an insect sting, dislodging the stinger with the edge of a credit card or coin. Patients should not attempt to pull the stinger out of the skin.
Respiratory and cardiovascular support — The initial treatment of anaphylaxis addresses any life-threatening respiratory and cardiovascular symptoms. This treatment may require inserting a breathing (endotracheal) tube to keep a person's airways open. Treatment may also include medications to treat low blood pressure and cardiac arrhythmias (irregular heart beat).
Drug therapy — Many different drugs are used to treat anaphylaxis, including epinephrine, asthma medications, antihistamines, and corticosteroids. Intravenous fluids are also frequently used to increase and maintain blood pressure.
Epinephrine is the most effective drug for the treatment of anaphylaxis. It treats all the symptoms of anaphylaxis, and is the most important treatment for the severe symptoms that can occur: low blood pressure, chest tightness or wheezing, and throat closure. (See "Patient information: Use of an epinephrine autoinjector").
Antihistamines can be given by injection or pill, and are almost always given to patients during anaphylaxis. Inhaled medications, such as albuterol, are given during anaphylaxis if a person has difficulty breathing, chest tightness, or coughing. Corticosteroids, such as prednisone, do not work rapidly enough to stop the immediate signs and symptoms of anaphylaxis. However, they may prevent a recurrence in the hours following an anaphylactic reaction and prevent late reactions, such as asthma attacks.
PREVENTION — Anaphylaxis is a frightening experience for the person who suffers the reaction, as well as for the people around him or her. It is normal to worry about future reactions. A few simple measures can reduce this risk.
Allergist evaluation — Anyone who has experienced an anaphylactic reaction should be evaluated by an allergist - a doctor who specializes in the diagnosis and treatment of allergies and related conditions. An allergist may recommend skin tests or blood testing to help identify the stimuli that triggered anaphylaxis. As stated above, a specific trigger cannot be identified in all cases, although an allergist can provide advice about how best to manage this situation as well.
Avoiding triggers — When a trigger can be identified, it can often be avoided. For example, a person with a known food allergy may be able to prevent anaphylactic reactions by carefully eliminating that food from their diet. A healthcare provider can provide strategies for identifying the food in processed products and when dining out.
Eliminating a food requires that a person carefully read food labels on everything they plan to eat, not just the foods that are most likely to contain the allergy trigger. The United States Food Allergen Labeling and Consumer Protection Act (which affects foods labeled on or after January 2006) requires that the nutrition labels on food packages clearly identify eight potential allergy triggers: milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, and soybeans. Other potential allergy triggers may be identified with names that are less clear (eg, spices, flavorings, or colorings that may cause an allergic reaction). In addition, "substitute" foods that are used to lower the fat content or replace other components of a food may not remove the allergenic proteins. As an example, some egg substitutes (which are lower in cholesterol) still contain egg white proteins.
People with allergies to bees, wasps, or hornets can wear protective clothing, learn to stay calm around insects, avoid wearing scented sprays or lotions, and take care when outdoors to reduce the likelihood of being stung.
Wear a device identifying the allergy — People who have allergies or have experienced an anaphylactic reaction should wear a bracelet, necklace, or similar alert tag at all times. If another 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.
Other preventive measures — Other measures to prevent future episodes of anaphylaxis include immunotherapy (injections to reduce sensitivity) for bee and wasp stings, antibiotic desensitization, and premedication with antihistamines and corticosteroids before radiocontrast administration.
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)
Anaphylaxis Foundation and Anaphylaxis Network of Canada
(www.anaphylaxis.org)
The Anaphylaxis Campaign
(www.anaphylaxis.org.uk)
[1-9]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Sicherer, SH. Food allergy: when and how to perform oral food challenges. Pediatr Allergy Immunol 1999; 10:226.
2. Bock, SA, Burks, AW. Taking action against anaphylaxis. Contemp Pediatr 1999; 16:87.
3. Bochner, BS, Lichtenstein, LM. Anaphylaxis. N Engl J Med 1991; 324:1785.
4. Ewan, PW. Anaphylaxis. BMJ 1998; 316:1442.
5. Fisher, M. Treatment of acute anaphylaxis. BMJ 1995; 311:731.
6. Kemp, SF, Lockey, RF, Wolf, BL, Lieberman, P. Anaphylaxis: Review of 266 cases. Arch Intern Med 1995; 155:1749.
7. Chamberlain, D. Emergency medical treatment of anaphylactic reactions. Project Team of the Resuscitation Council (UK). J Accid Emerg Med 1999; 16:243.
8. Golden, DB. Patterns of anaphylaxis: acute and late phase features of allergic reactions. Novartis Found Symp 2004; 257:101.
9. Pumphrey, R. Anaphylaxis: can we tell who is at risk of a fatal reaction?. Curr Opin Allergy Clin Immunol 2004; 4:285.
Every year, about 500 to 1000 people die from severe anaphylaxis. However, many more people likely experience mild or moderate anaphylaxis and do not seek medical care. As a result, the true frequency of anaphylaxis is unknown.
The severity of anaphylactic reactions can be minimized by recognizing the symptoms early, having the proper medications available for self-treatment, and seeking emergency medical care promptly. It is also important to try to identify the specific trigger for each person, although this is not always possible.
PHYSIOLOGY — Anaphylaxis occurs when a trigger activates immune cells, which then release large amounts of multiple substances, including histamine, into the blood stream. This sets off a number of reactions, including itching, dilated blood vessels (leading to low blood pressure and rapid heart rate), mucus secretion, stimulation of the nervous system, and activation of other cells of the immune system. These reactions cause the symptoms that are commonly associated with anaphylaxis.
In some people with anaphylaxis, abnormal antibodies called IgE (proteins that normally fight infections and protect the body) are made in response to non-harmful things, like food or medicines. These IgE antibodies can trigger a violent immune response when the person is later exposed to that food or medicine. The immune response is so strong and uncontrolled that the reaction itself can be harmful. In other people with anaphylaxis, these abnormal IgE proteins are not found, and the reaction is thought to have been caused by other processes.
SYMPTOMS — Symptoms of anaphylaxis generally begin within 5 to 60 minutes of exposure to a trigger. Some patients may not develop symptoms for several hours.
Anaphylaxis can produce symptoms throughout the body: Skin: Itching, flushing, urticaria (hives), and angioedema (swelling). Eyes: Itching, tearing, and swelling of the tissues around the eyes. Nose and mouth: Sneezing, runny nose, nasal congestion, itching of the mouth, and a metallic taste. Lungs and throat: Difficulty breathing, wheezing, increased airway secretions, swelling of the upper throat and/or tongue, hoarseness, sounds of labored breathing, and a sensation of choking. Heart: Very rapid heartbeat, arrhythmia (an irregular heart beat), low blood pressure, and cardiac arrest (a cessation of the heart's pumping action). Digestive system: Nausea, vomiting, abdominal cramps, bloating, and diarrhea. Nervous system: Dizziness, weakness, fainting, and a sense of impending doom.
The most common symptoms of anaphylaxis are urticaria (hives) and angioedema (swelling of the tissues under the skin), which occur in nearly 90 percent of people who have anaphylaxis. These symptoms usually begin after a period of generalized itching, flushing, and sometimes a growing sense of impending doom.
Respiratory symptoms occur in about 50 percent of people who have anaphylaxis and are especially common in people who also have asthma. Gastrointestinal symptoms occur in 30 percent of people. Anaphylactic shock (extremely low blood pressure) occurs in 30 percent of people who have a reaction. Low blood pressure can cause lightheadedness, dizziness, tunnel vision, and loss of consciousness (passing out). These are serious symptoms.
Less commonly, a person may have biphasic or protracted anaphylaxis. A patient with biphasic anaphylaxis has a reaction that resolves but recurs one to eight hours later; second reactions have occurred as much as 72 hours later. A patient with protracted anaphylaxis has signs and symptoms that persist for up to 48 hours despite treatment.
CAUSES — Anaphylaxis triggers can include: Foods, especially seafood, milk, peanuts and tree nuts Drugs, especially certain antibiotics (such as penicillin), nonsteroidal anti-inflammatory drugs (such as aspirin or ibuprofen), drugs used for chemotherapy, and angiotensin-converting enzyme (ACE) inhibitors (See "Patient information: Allergy to penicillin and other antibiotics") Venom from insects, including bees, wasps, kissing bugs, and fire ants Some substances used during x-ray procedures (radiocontrast media) Transfused blood and blood products Exercise or exertion Latex from natural rubber, used to make gloves, balloons, and some medical products
In some cases, a thorough evaluation by an allergy specialist will not identify any specific trigger. This condition is called idiopathic anaphylaxis and is more common in adults than in children.
Food allergies in children — Anaphylaxis in children often results from food allergies. Food allergies are most likely to develop in the first three years of life, when many foods are introduced into a child's diet. Allergies to hen's egg, peanuts, cow's milk, soy, fish, and wheat are among the most common food allergies that children develop. In children over the age of three years, peanuts are the most common allergen. Children often outgrow allergies to milk, eggs, and soybeans. However, allergies to peanuts, other tree nuts, fish and seafood tend to persist.
RISK FACTORS — Several factors help to predict which individuals are most likely to experience anaphylaxis and which factors are most likely to trigger anaphylaxis in specific groups of people.
Age — Children are more likely than adults to have anaphylactic reactions to foods. Adults are more likely to have anaphylactic reactions to antibiotics, radiocontrast media, insect stings, anesthetic drugs, and certain intravenous medicines. They are also more likely to have idiopathic anaphylaxis.
Gender — Overall, women are somewhat more likely to experience anaphylaxis.
Asthma — People with asthma are more likely to experience anaphylaxis and to have more severe respiratory problems during anaphylaxis. The combination of food allergy (especially to peanuts and tree nuts) and asthma seems to put people at risk for particularly dangerous attacks of anaphylaxis.
History of anaphylaxis — People who have had an anaphylactic reaction in the past are at increased risk of future anaphylactic reactions. For example, people who have had an anaphylactic reaction to certain antibiotics are four to six times more likely to have another reaction to these antibiotics when compared to the general population. Similarly, 60 percent of people who have had an allergic reaction to a bee or wasp sting have a severe reaction if stung again, and up to 40 percent of people who have had a reaction to radiocontrast media have a repeat reaction if they are given it again (unless they are given medications to prevent a reaction).
Multiple exposures — People who are exposed to several different allergic stimuli at the same time have an increased risk of anaphylaxis. For example, people who receive immunotherapy (regular injections, also called allergy shots) to decrease a their sensitivity to allergens are more likely to have a severe reaction to their injections during the season(s) when natural exposure is greatest (eg, allergy season, usually spring and fall in most regions of the United States).
DIAGNOSIS — The diagnosis of anaphylaxis is usually based upon the presence of characteristics symptoms, particularly if there is an accompanying story of exposure to a potential trigger, such as a new medicine or insect sting.
However, other problems, such as food poisoning, a severe asthma attack, or cardiac events, can sometimes look like anaphylaxis. In such cases, further evaluation by allergists or other specialists may be needed to clarify the diagnosis. In some cases, the diagnosis of anaphylaxis is difficult to establish.
TREATMENT — A patient who has had an anaphylactic reaction should talk with their healthcare provider to design a plan for responding to future reactions. A plan can minimize the severity of an anaphylactic reaction and ensure that the best treatments are given. Many people find that developing a plan is reassuring, even if it is never needed.
Because anaphylaxis can be life-threatening, it should be treated as an emergency. Most people with moderate to severe anaphylaxis are hospitalized for observation, even when emergency treatment brings the symptoms under control. This hospitalization enables prompt treatment if the symptoms reappear several hours later.
Self-treatment — Patients with allergies or who have a history of anaphylaxis should always carry two epinephrine autoinjectors. A full description of epinephrine autoinjectors is available separately. (See "Patient information: Use of an epinephrine autoinjector").
Remove the cause — The trigger for the anaphylactic reaction should be promptly removed, whenever possible. This removal may entail stopping a drug, or in the case of an insect sting, dislodging the stinger with the edge of a credit card or coin. Patients should not attempt to pull the stinger out of the skin.
Respiratory and cardiovascular support — The initial treatment of anaphylaxis addresses any life-threatening respiratory and cardiovascular symptoms. This treatment may require inserting a breathing (endotracheal) tube to keep a person's airways open. Treatment may also include medications to treat low blood pressure and cardiac arrhythmias (irregular heart beat).
Drug therapy — Many different drugs are used to treat anaphylaxis, including epinephrine, asthma medications, antihistamines, and corticosteroids. Intravenous fluids are also frequently used to increase and maintain blood pressure.
Epinephrine is the most effective drug for the treatment of anaphylaxis. It treats all the symptoms of anaphylaxis, and is the most important treatment for the severe symptoms that can occur: low blood pressure, chest tightness or wheezing, and throat closure. (See "Patient information: Use of an epinephrine autoinjector").
Antihistamines can be given by injection or pill, and are almost always given to patients during anaphylaxis. Inhaled medications, such as albuterol, are given during anaphylaxis if a person has difficulty breathing, chest tightness, or coughing. Corticosteroids, such as prednisone, do not work rapidly enough to stop the immediate signs and symptoms of anaphylaxis. However, they may prevent a recurrence in the hours following an anaphylactic reaction and prevent late reactions, such as asthma attacks.
PREVENTION — Anaphylaxis is a frightening experience for the person who suffers the reaction, as well as for the people around him or her. It is normal to worry about future reactions. A few simple measures can reduce this risk.
Allergist evaluation — Anyone who has experienced an anaphylactic reaction should be evaluated by an allergist - a doctor who specializes in the diagnosis and treatment of allergies and related conditions. An allergist may recommend skin tests or blood testing to help identify the stimuli that triggered anaphylaxis. As stated above, a specific trigger cannot be identified in all cases, although an allergist can provide advice about how best to manage this situation as well.
Avoiding triggers — When a trigger can be identified, it can often be avoided. For example, a person with a known food allergy may be able to prevent anaphylactic reactions by carefully eliminating that food from their diet. A healthcare provider can provide strategies for identifying the food in processed products and when dining out.
Eliminating a food requires that a person carefully read food labels on everything they plan to eat, not just the foods that are most likely to contain the allergy trigger. The United States Food Allergen Labeling and Consumer Protection Act (which affects foods labeled on or after January 2006) requires that the nutrition labels on food packages clearly identify eight potential allergy triggers: milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, and soybeans. Other potential allergy triggers may be identified with names that are less clear (eg, spices, flavorings, or colorings that may cause an allergic reaction). In addition, "substitute" foods that are used to lower the fat content or replace other components of a food may not remove the allergenic proteins. As an example, some egg substitutes (which are lower in cholesterol) still contain egg white proteins.
People with allergies to bees, wasps, or hornets can wear protective clothing, learn to stay calm around insects, avoid wearing scented sprays or lotions, and take care when outdoors to reduce the likelihood of being stung.
Wear a device identifying the allergy — People who have allergies or have experienced an anaphylactic reaction should wear a bracelet, necklace, or similar alert tag at all times. If another 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.
Other preventive measures — Other measures to prevent future episodes of anaphylaxis include immunotherapy (injections to reduce sensitivity) for bee and wasp stings, antibiotic desensitization, and premedication with antihistamines and corticosteroids before radiocontrast administration.
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)
Anaphylaxis Foundation and Anaphylaxis Network of Canada
(www.anaphylaxis.org)
The Anaphylaxis Campaign
(www.anaphylaxis.org.uk)
[1-9]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Sicherer, SH. Food allergy: when and how to perform oral food challenges. Pediatr Allergy Immunol 1999; 10:226.
2. Bock, SA, Burks, AW. Taking action against anaphylaxis. Contemp Pediatr 1999; 16:87.
3. Bochner, BS, Lichtenstein, LM. Anaphylaxis. N Engl J Med 1991; 324:1785.
4. Ewan, PW. Anaphylaxis. BMJ 1998; 316:1442.
5. Fisher, M. Treatment of acute anaphylaxis. BMJ 1995; 311:731.
6. Kemp, SF, Lockey, RF, Wolf, BL, Lieberman, P. Anaphylaxis: Review of 266 cases. Arch Intern Med 1995; 155:1749.
7. Chamberlain, D. Emergency medical treatment of anaphylactic reactions. Project Team of the Resuscitation Council (UK). J Accid Emerg Med 1999; 16:243.
8. Golden, DB. Patterns of anaphylaxis: acute and late phase features of allergic reactions. Novartis Found Symp 2004; 257:101.
9. Pumphrey, R. Anaphylaxis: can we tell who is at risk of a fatal reaction?. Curr Opin Allergy Clin Immunol 2004; 4:285.
ASTHMA Patient information: Anaphylaxis
INTRODUCTION — Anaphylaxis is a sudden, potentially life-threatening allergic reaction. Allergic reactions can be triggered by foods, medications, exercise, latex, or insect stings, or unknown triggers.
Every year, about 500 to 1000 people die from severe anaphylaxis. However, many more people likely experience mild or moderate anaphylaxis and do not seek medical care. As a result, the true frequency of anaphylaxis is unknown.
The severity of anaphylactic reactions can be minimized by recognizing the symptoms early, having the proper medications available for self-treatment, and seeking emergency medical care promptly. It is also important to try to identify the specific trigger for each person, although this is not always possible.
PHYSIOLOGY — Anaphylaxis occurs when a trigger activates immune cells, which then release large amounts of multiple substances, including histamine, into the blood stream. This sets off a number of reactions, including itching, dilated blood vessels (leading to low blood pressure and rapid heart rate), mucus secretion, stimulation of the nervous system, and activation of other cells of the immune system. These reactions cause the symptoms that are commonly associated with anaphylaxis.
In some people with anaphylaxis, abnormal antibodies called IgE (proteins that normally fight infections and protect the body) are made in response to non-harmful things, like food or medicines. These IgE antibodies can trigger a violent immune response when the person is later exposed to that food or medicine. The immune response is so strong and uncontrolled that the reaction itself can be harmful. In other people with anaphylaxis, these abnormal IgE proteins are not found, and the reaction is thought to have been caused by other processes.
SYMPTOMS — Symptoms of anaphylaxis generally begin within 5 to 60 minutes of exposure to a trigger. Some patients may not develop symptoms for several hours.
Anaphylaxis can produce symptoms throughout the body: Skin: Itching, flushing, urticaria (hives), and angioedema (swelling). Eyes: Itching, tearing, and swelling of the tissues around the eyes. Nose and mouth: Sneezing, runny nose, nasal congestion, itching of the mouth, and a metallic taste. Lungs and throat: Difficulty breathing, wheezing, increased airway secretions, swelling of the upper throat and/or tongue, hoarseness, sounds of labored breathing, and a sensation of choking. Heart: Very rapid heartbeat, arrhythmia (an irregular heart beat), low blood pressure, and cardiac arrest (a cessation of the heart's pumping action). Digestive system: Nausea, vomiting, abdominal cramps, bloating, and diarrhea. Nervous system: Dizziness, weakness, fainting, and a sense of impending doom.
The most common symptoms of anaphylaxis are urticaria (hives) and angioedema (swelling of the tissues under the skin), which occur in nearly 90 percent of people who have anaphylaxis. These symptoms usually begin after a period of generalized itching, flushing, and sometimes a growing sense of impending doom.
Respiratory symptoms occur in about 50 percent of people who have anaphylaxis and are especially common in people who also have asthma. Gastrointestinal symptoms occur in 30 percent of people. Anaphylactic shock (extremely low blood pressure) occurs in 30 percent of people who have a reaction. Low blood pressure can cause lightheadedness, dizziness, tunnel vision, and loss of consciousness (passing out). These are serious symptoms.
Less commonly, a person may have biphasic or protracted anaphylaxis. A patient with biphasic anaphylaxis has a reaction that resolves but recurs one to eight hours later; second reactions have occurred as much as 72 hours later. A patient with protracted anaphylaxis has signs and symptoms that persist for up to 48 hours despite treatment.
CAUSES — Anaphylaxis triggers can include: Foods, especially seafood, milk, peanuts and tree nuts Drugs, especially certain antibiotics (such as penicillin), nonsteroidal anti-inflammatory drugs (such as aspirin or ibuprofen), drugs used for chemotherapy, and angiotensin-converting enzyme (ACE) inhibitors (See "Patient information: Allergy to penicillin and other antibiotics") Venom from insects, including bees, wasps, kissing bugs, and fire ants Some substances used during x-ray procedures (radiocontrast media) Transfused blood and blood products Exercise or exertion Latex from natural rubber, used to make gloves, balloons, and some medical products
In some cases, a thorough evaluation by an allergy specialist will not identify any specific trigger. This condition is called idiopathic anaphylaxis and is more common in adults than in children.
Food allergies in children — Anaphylaxis in children often results from food allergies. Food allergies are most likely to develop in the first three years of life, when many foods are introduced into a child's diet. Allergies to hen's egg, peanuts, cow's milk, soy, fish, and wheat are among the most common food allergies that children develop. In children over the age of three years, peanuts are the most common allergen. Children often outgrow allergies to milk, eggs, and soybeans. However, allergies to peanuts, other tree nuts, fish and seafood tend to persist.
RISK FACTORS — Several factors help to predict which individuals are most likely to experience anaphylaxis and which factors are most likely to trigger anaphylaxis in specific groups of people.
Age — Children are more likely than adults to have anaphylactic reactions to foods. Adults are more likely to have anaphylactic reactions to antibiotics, radiocontrast media, insect stings, anesthetic drugs, and certain intravenous medicines. They are also more likely to have idiopathic anaphylaxis.
Gender — Overall, women are somewhat more likely to experience anaphylaxis.
Asthma — People with asthma are more likely to experience anaphylaxis and to have more severe respiratory problems during anaphylaxis. The combination of food allergy (especially to peanuts and tree nuts) and asthma seems to put people at risk for particularly dangerous attacks of anaphylaxis.
History of anaphylaxis — People who have had an anaphylactic reaction in the past are at increased risk of future anaphylactic reactions. For example, people who have had an anaphylactic reaction to certain antibiotics are four to six times more likely to have another reaction to these antibiotics when compared to the general population. Similarly, 60 percent of people who have had an allergic reaction to a bee or wasp sting have a severe reaction if stung again, and up to 40 percent of people who have had a reaction to radiocontrast media have a repeat reaction if they are given it again (unless they are given medications to prevent a reaction).
Multiple exposures — People who are exposed to several different allergic stimuli at the same time have an increased risk of anaphylaxis. For example, people who receive immunotherapy (regular injections, also called allergy shots) to decrease a their sensitivity to allergens are more likely to have a severe reaction to their injections during the season(s) when natural exposure is greatest (eg, allergy season, usually spring and fall in most regions of the United States).
DIAGNOSIS — The diagnosis of anaphylaxis is usually based upon the presence of characteristics symptoms, particularly if there is an accompanying story of exposure to a potential trigger, such as a new medicine or insect sting.
However, other problems, such as food poisoning, a severe asthma attack, or cardiac events, can sometimes look like anaphylaxis. In such cases, further evaluation by allergists or other specialists may be needed to clarify the diagnosis. In some cases, the diagnosis of anaphylaxis is difficult to establish.
TREATMENT — A patient who has had an anaphylactic reaction should talk with their healthcare provider to design a plan for responding to future reactions. A plan can minimize the severity of an anaphylactic reaction and ensure that the best treatments are given. Many people find that developing a plan is reassuring, even if it is never needed.
Because anaphylaxis can be life-threatening, it should be treated as an emergency. Most people with moderate to severe anaphylaxis are hospitalized for observation, even when emergency treatment brings the symptoms under control. This hospitalization enables prompt treatment if the symptoms reappear several hours later.
Self-treatment — Patients with allergies or who have a history of anaphylaxis should always carry two epinephrine autoinjectors. A full description of epinephrine autoinjectors is available separately. (See "Patient information: Use of an epinephrine autoinjector").
Remove the cause — The trigger for the anaphylactic reaction should be promptly removed, whenever possible. This removal may entail stopping a drug, or in the case of an insect sting, dislodging the stinger with the edge of a credit card or coin. Patients should not attempt to pull the stinger out of the skin.
Respiratory and cardiovascular support — The initial treatment of anaphylaxis addresses any life-threatening respiratory and cardiovascular symptoms. This treatment may require inserting a breathing (endotracheal) tube to keep a person's airways open. Treatment may also include medications to treat low blood pressure and cardiac arrhythmias (irregular heart beat).
Drug therapy — Many different drugs are used to treat anaphylaxis, including epinephrine, asthma medications, antihistamines, and corticosteroids. Intravenous fluids are also frequently used to increase and maintain blood pressure.
Epinephrine is the most effective drug for the treatment of anaphylaxis. It treats all the symptoms of anaphylaxis, and is the most important treatment for the severe symptoms that can occur: low blood pressure, chest tightness or wheezing, and throat closure. (See "Patient information: Use of an epinephrine autoinjector").
Antihistamines can be given by injection or pill, and are almost always given to patients during anaphylaxis. Inhaled medications, such as albuterol, are given during anaphylaxis if a person has difficulty breathing, chest tightness, or coughing. Corticosteroids, such as prednisone, do not work rapidly enough to stop the immediate signs and symptoms of anaphylaxis. However, they may prevent a recurrence in the hours following an anaphylactic reaction and prevent late reactions, such as asthma attacks.
PREVENTION — Anaphylaxis is a frightening experience for the person who suffers the reaction, as well as for the people around him or her. It is normal to worry about future reactions. A few simple measures can reduce this risk.
Allergist evaluation — Anyone who has experienced an anaphylactic reaction should be evaluated by an allergist - a doctor who specializes in the diagnosis and treatment of allergies and related conditions. An allergist may recommend skin tests or blood testing to help identify the stimuli that triggered anaphylaxis. As stated above, a specific trigger cannot be identified in all cases, although an allergist can provide advice about how best to manage this situation as well.
Avoiding triggers — When a trigger can be identified, it can often be avoided. For example, a person with a known food allergy may be able to prevent anaphylactic reactions by carefully eliminating that food from their diet. A healthcare provider can provide strategies for identifying the food in processed products and when dining out.
Eliminating a food requires that a person carefully read food labels on everything they plan to eat, not just the foods that are most likely to contain the allergy trigger. The United States Food Allergen Labeling and Consumer Protection Act (which affects foods labeled on or after January 2006) requires that the nutrition labels on food packages clearly identify eight potential allergy triggers: milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, and soybeans. Other potential allergy triggers may be identified with names that are less clear (eg, spices, flavorings, or colorings that may cause an allergic reaction). In addition, "substitute" foods that are used to lower the fat content or replace other components of a food may not remove the allergenic proteins. As an example, some egg substitutes (which are lower in cholesterol) still contain egg white proteins.
People with allergies to bees, wasps, or hornets can wear protective clothing, learn to stay calm around insects, avoid wearing scented sprays or lotions, and take care when outdoors to reduce the likelihood of being stung.
Wear a device identifying the allergy — People who have allergies or have experienced an anaphylactic reaction should wear a bracelet, necklace, or similar alert tag at all times. If another 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.
Other preventive measures — Other measures to prevent future episodes of anaphylaxis include immunotherapy (injections to reduce sensitivity) for bee and wasp stings, antibiotic desensitization, and premedication with antihistamines and corticosteroids before radiocontrast administration.
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)
Anaphylaxis Foundation and Anaphylaxis Network of Canada
(www.anaphylaxis.org)
The Anaphylaxis Campaign
(www.anaphylaxis.org.uk)
[1-9]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Sicherer, SH. Food allergy: when and how to perform oral food challenges. Pediatr Allergy Immunol 1999; 10:226.
2. Bock, SA, Burks, AW. Taking action against anaphylaxis. Contemp Pediatr 1999; 16:87.
3. Bochner, BS, Lichtenstein, LM. Anaphylaxis. N Engl J Med 1991; 324:1785.
4. Ewan, PW. Anaphylaxis. BMJ 1998; 316:1442.
5. Fisher, M. Treatment of acute anaphylaxis. BMJ 1995; 311:731.
6. Kemp, SF, Lockey, RF, Wolf, BL, Lieberman, P. Anaphylaxis: Review of 266 cases. Arch Intern Med 1995; 155:1749.
7. Chamberlain, D. Emergency medical treatment of anaphylactic reactions. Project Team of the Resuscitation Council (UK). J Accid Emerg Med 1999; 16:243.
8. Golden, DB. Patterns of anaphylaxis: acute and late phase features of allergic reactions. Novartis Found Symp 2004; 257:101.
9. Pumphrey, R. Anaphylaxis: can we tell who is at risk of a fatal reaction?. Curr Opin Allergy Clin Immunol 2004; 4:285.
Every year, about 500 to 1000 people die from severe anaphylaxis. However, many more people likely experience mild or moderate anaphylaxis and do not seek medical care. As a result, the true frequency of anaphylaxis is unknown.
The severity of anaphylactic reactions can be minimized by recognizing the symptoms early, having the proper medications available for self-treatment, and seeking emergency medical care promptly. It is also important to try to identify the specific trigger for each person, although this is not always possible.
PHYSIOLOGY — Anaphylaxis occurs when a trigger activates immune cells, which then release large amounts of multiple substances, including histamine, into the blood stream. This sets off a number of reactions, including itching, dilated blood vessels (leading to low blood pressure and rapid heart rate), mucus secretion, stimulation of the nervous system, and activation of other cells of the immune system. These reactions cause the symptoms that are commonly associated with anaphylaxis.
In some people with anaphylaxis, abnormal antibodies called IgE (proteins that normally fight infections and protect the body) are made in response to non-harmful things, like food or medicines. These IgE antibodies can trigger a violent immune response when the person is later exposed to that food or medicine. The immune response is so strong and uncontrolled that the reaction itself can be harmful. In other people with anaphylaxis, these abnormal IgE proteins are not found, and the reaction is thought to have been caused by other processes.
SYMPTOMS — Symptoms of anaphylaxis generally begin within 5 to 60 minutes of exposure to a trigger. Some patients may not develop symptoms for several hours.
Anaphylaxis can produce symptoms throughout the body: Skin: Itching, flushing, urticaria (hives), and angioedema (swelling). Eyes: Itching, tearing, and swelling of the tissues around the eyes. Nose and mouth: Sneezing, runny nose, nasal congestion, itching of the mouth, and a metallic taste. Lungs and throat: Difficulty breathing, wheezing, increased airway secretions, swelling of the upper throat and/or tongue, hoarseness, sounds of labored breathing, and a sensation of choking. Heart: Very rapid heartbeat, arrhythmia (an irregular heart beat), low blood pressure, and cardiac arrest (a cessation of the heart's pumping action). Digestive system: Nausea, vomiting, abdominal cramps, bloating, and diarrhea. Nervous system: Dizziness, weakness, fainting, and a sense of impending doom.
The most common symptoms of anaphylaxis are urticaria (hives) and angioedema (swelling of the tissues under the skin), which occur in nearly 90 percent of people who have anaphylaxis. These symptoms usually begin after a period of generalized itching, flushing, and sometimes a growing sense of impending doom.
Respiratory symptoms occur in about 50 percent of people who have anaphylaxis and are especially common in people who also have asthma. Gastrointestinal symptoms occur in 30 percent of people. Anaphylactic shock (extremely low blood pressure) occurs in 30 percent of people who have a reaction. Low blood pressure can cause lightheadedness, dizziness, tunnel vision, and loss of consciousness (passing out). These are serious symptoms.
Less commonly, a person may have biphasic or protracted anaphylaxis. A patient with biphasic anaphylaxis has a reaction that resolves but recurs one to eight hours later; second reactions have occurred as much as 72 hours later. A patient with protracted anaphylaxis has signs and symptoms that persist for up to 48 hours despite treatment.
CAUSES — Anaphylaxis triggers can include: Foods, especially seafood, milk, peanuts and tree nuts Drugs, especially certain antibiotics (such as penicillin), nonsteroidal anti-inflammatory drugs (such as aspirin or ibuprofen), drugs used for chemotherapy, and angiotensin-converting enzyme (ACE) inhibitors (See "Patient information: Allergy to penicillin and other antibiotics") Venom from insects, including bees, wasps, kissing bugs, and fire ants Some substances used during x-ray procedures (radiocontrast media) Transfused blood and blood products Exercise or exertion Latex from natural rubber, used to make gloves, balloons, and some medical products
In some cases, a thorough evaluation by an allergy specialist will not identify any specific trigger. This condition is called idiopathic anaphylaxis and is more common in adults than in children.
Food allergies in children — Anaphylaxis in children often results from food allergies. Food allergies are most likely to develop in the first three years of life, when many foods are introduced into a child's diet. Allergies to hen's egg, peanuts, cow's milk, soy, fish, and wheat are among the most common food allergies that children develop. In children over the age of three years, peanuts are the most common allergen. Children often outgrow allergies to milk, eggs, and soybeans. However, allergies to peanuts, other tree nuts, fish and seafood tend to persist.
RISK FACTORS — Several factors help to predict which individuals are most likely to experience anaphylaxis and which factors are most likely to trigger anaphylaxis in specific groups of people.
Age — Children are more likely than adults to have anaphylactic reactions to foods. Adults are more likely to have anaphylactic reactions to antibiotics, radiocontrast media, insect stings, anesthetic drugs, and certain intravenous medicines. They are also more likely to have idiopathic anaphylaxis.
Gender — Overall, women are somewhat more likely to experience anaphylaxis.
Asthma — People with asthma are more likely to experience anaphylaxis and to have more severe respiratory problems during anaphylaxis. The combination of food allergy (especially to peanuts and tree nuts) and asthma seems to put people at risk for particularly dangerous attacks of anaphylaxis.
History of anaphylaxis — People who have had an anaphylactic reaction in the past are at increased risk of future anaphylactic reactions. For example, people who have had an anaphylactic reaction to certain antibiotics are four to six times more likely to have another reaction to these antibiotics when compared to the general population. Similarly, 60 percent of people who have had an allergic reaction to a bee or wasp sting have a severe reaction if stung again, and up to 40 percent of people who have had a reaction to radiocontrast media have a repeat reaction if they are given it again (unless they are given medications to prevent a reaction).
Multiple exposures — People who are exposed to several different allergic stimuli at the same time have an increased risk of anaphylaxis. For example, people who receive immunotherapy (regular injections, also called allergy shots) to decrease a their sensitivity to allergens are more likely to have a severe reaction to their injections during the season(s) when natural exposure is greatest (eg, allergy season, usually spring and fall in most regions of the United States).
DIAGNOSIS — The diagnosis of anaphylaxis is usually based upon the presence of characteristics symptoms, particularly if there is an accompanying story of exposure to a potential trigger, such as a new medicine or insect sting.
However, other problems, such as food poisoning, a severe asthma attack, or cardiac events, can sometimes look like anaphylaxis. In such cases, further evaluation by allergists or other specialists may be needed to clarify the diagnosis. In some cases, the diagnosis of anaphylaxis is difficult to establish.
TREATMENT — A patient who has had an anaphylactic reaction should talk with their healthcare provider to design a plan for responding to future reactions. A plan can minimize the severity of an anaphylactic reaction and ensure that the best treatments are given. Many people find that developing a plan is reassuring, even if it is never needed.
Because anaphylaxis can be life-threatening, it should be treated as an emergency. Most people with moderate to severe anaphylaxis are hospitalized for observation, even when emergency treatment brings the symptoms under control. This hospitalization enables prompt treatment if the symptoms reappear several hours later.
Self-treatment — Patients with allergies or who have a history of anaphylaxis should always carry two epinephrine autoinjectors. A full description of epinephrine autoinjectors is available separately. (See "Patient information: Use of an epinephrine autoinjector").
Remove the cause — The trigger for the anaphylactic reaction should be promptly removed, whenever possible. This removal may entail stopping a drug, or in the case of an insect sting, dislodging the stinger with the edge of a credit card or coin. Patients should not attempt to pull the stinger out of the skin.
Respiratory and cardiovascular support — The initial treatment of anaphylaxis addresses any life-threatening respiratory and cardiovascular symptoms. This treatment may require inserting a breathing (endotracheal) tube to keep a person's airways open. Treatment may also include medications to treat low blood pressure and cardiac arrhythmias (irregular heart beat).
Drug therapy — Many different drugs are used to treat anaphylaxis, including epinephrine, asthma medications, antihistamines, and corticosteroids. Intravenous fluids are also frequently used to increase and maintain blood pressure.
Epinephrine is the most effective drug for the treatment of anaphylaxis. It treats all the symptoms of anaphylaxis, and is the most important treatment for the severe symptoms that can occur: low blood pressure, chest tightness or wheezing, and throat closure. (See "Patient information: Use of an epinephrine autoinjector").
Antihistamines can be given by injection or pill, and are almost always given to patients during anaphylaxis. Inhaled medications, such as albuterol, are given during anaphylaxis if a person has difficulty breathing, chest tightness, or coughing. Corticosteroids, such as prednisone, do not work rapidly enough to stop the immediate signs and symptoms of anaphylaxis. However, they may prevent a recurrence in the hours following an anaphylactic reaction and prevent late reactions, such as asthma attacks.
PREVENTION — Anaphylaxis is a frightening experience for the person who suffers the reaction, as well as for the people around him or her. It is normal to worry about future reactions. A few simple measures can reduce this risk.
Allergist evaluation — Anyone who has experienced an anaphylactic reaction should be evaluated by an allergist - a doctor who specializes in the diagnosis and treatment of allergies and related conditions. An allergist may recommend skin tests or blood testing to help identify the stimuli that triggered anaphylaxis. As stated above, a specific trigger cannot be identified in all cases, although an allergist can provide advice about how best to manage this situation as well.
Avoiding triggers — When a trigger can be identified, it can often be avoided. For example, a person with a known food allergy may be able to prevent anaphylactic reactions by carefully eliminating that food from their diet. A healthcare provider can provide strategies for identifying the food in processed products and when dining out.
Eliminating a food requires that a person carefully read food labels on everything they plan to eat, not just the foods that are most likely to contain the allergy trigger. The United States Food Allergen Labeling and Consumer Protection Act (which affects foods labeled on or after January 2006) requires that the nutrition labels on food packages clearly identify eight potential allergy triggers: milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, and soybeans. Other potential allergy triggers may be identified with names that are less clear (eg, spices, flavorings, or colorings that may cause an allergic reaction). In addition, "substitute" foods that are used to lower the fat content or replace other components of a food may not remove the allergenic proteins. As an example, some egg substitutes (which are lower in cholesterol) still contain egg white proteins.
People with allergies to bees, wasps, or hornets can wear protective clothing, learn to stay calm around insects, avoid wearing scented sprays or lotions, and take care when outdoors to reduce the likelihood of being stung.
Wear a device identifying the allergy — People who have allergies or have experienced an anaphylactic reaction should wear a bracelet, necklace, or similar alert tag at all times. If another 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.
Other preventive measures — Other measures to prevent future episodes of anaphylaxis include immunotherapy (injections to reduce sensitivity) for bee and wasp stings, antibiotic desensitization, and premedication with antihistamines and corticosteroids before radiocontrast administration.
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)
Anaphylaxis Foundation and Anaphylaxis Network of Canada
(www.anaphylaxis.org)
The Anaphylaxis Campaign
(www.anaphylaxis.org.uk)
[1-9]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Sicherer, SH. Food allergy: when and how to perform oral food challenges. Pediatr Allergy Immunol 1999; 10:226.
2. Bock, SA, Burks, AW. Taking action against anaphylaxis. Contemp Pediatr 1999; 16:87.
3. Bochner, BS, Lichtenstein, LM. Anaphylaxis. N Engl J Med 1991; 324:1785.
4. Ewan, PW. Anaphylaxis. BMJ 1998; 316:1442.
5. Fisher, M. Treatment of acute anaphylaxis. BMJ 1995; 311:731.
6. Kemp, SF, Lockey, RF, Wolf, BL, Lieberman, P. Anaphylaxis: Review of 266 cases. Arch Intern Med 1995; 155:1749.
7. Chamberlain, D. Emergency medical treatment of anaphylactic reactions. Project Team of the Resuscitation Council (UK). J Accid Emerg Med 1999; 16:243.
8. Golden, DB. Patterns of anaphylaxis: acute and late phase features of allergic reactions. Novartis Found Symp 2004; 257:101.
9. Pumphrey, R. Anaphylaxis: can we tell who is at risk of a fatal reaction?. Curr Opin Allergy Clin Immunol 2004; 4:285.
ASTHMA Patient information: Allergy to penicillin and other antibiotics
INTRODUCTION — Serious allergies to penicillin are common. True penicillin allergy is a leading cause of fatal drug reactions. However, many patients who believe they are allergic can take penicillin without a problem, either because they were never truly allergic or because their allergy to penicillin diminished over time.
Patients who have a remote history of allergic reaction to a medication may become less allergic as time passes. Only about 20 percent of patients will be allergic to penicillin 20 years after their initial allergic reaction if they are not exposed to it again during this time period.
TYPES OF PENICILLIN ALLERGY — Several different symptoms may develop after taking penicillin that can indicate that an allergy is present. These include hives (raised, intensely itchy spots that come and go over hours), angioedema (swelling of the tissue under the skin), wheezing and coughing from bronchospasm (narrowing of the airways into the lungs), and anaphylaxis.
Anaphylaxis — Anaphylaxis is a sudden, potentially life-threatening allergic reaction. Symptoms can include very low blood pressure, hives, difficulty breathing, abdominal pain, swelling of the throat or tongue, and diarrhea. Two to 4 percent of allergic reactions to penicillin are of this type. (See "Patient information: Anaphylaxis").
Less severe allergic reactions — A person may develop only hives or only angioedema, without other symptoms, while taking penicillin. This can be a sign that the person is allergic. If they were to take the medicine again, they might develop a more severe reaction, even anaphylaxis.
Rashes — Several different types of rashes can appear while people are taking penicillin. Rashes that involve hives are most suggestive of a true allergy rather than another type of reaction to penicillin. However, some people, especially young children, can develop flat, itchy, speckled rashes that do not involve hives. This type of rash is less likely to indicate a dangerous allergy, although it can be difficult to distinguish between different types of rashes if they happened in the past. Taking a photograph of a rash to show to doctors later is always helpful.
Adverse reactions — Some people have unpleasant side effects (called adverse reactions) after taking penicillin or other antibiotics. Adverse reactions are more common than true allergies, and may include stomach upset or other gastrointestinal reactions. Adverse reactions are not related to allergic reactions, and it is important to distinguish between the two. Persons who incorrectly report that they have had an allergic reaction may then be treated for a particular infection with a less-effective antibiotic. This can lead to antibiotic failure or resistance, which can be costly and prolong illness.
When reporting past problems with antibiotics, it is important to provide as much detail as possible about the reaction. Patients who are uncertain if a past allergic reaction was truly caused by allergy should avoid the antibiotic.
DIAGNOSIS — In some situations, it is necessary to determine with certainty if a person is allergic to penicillin. Testing for allergy is recommended in the following situations: Persons who have a suspected penicillin (or closely related antibiotic) allergy and require penicillin to treat a life-threatening condition for which no alternate antibiotic is appropriate Patients who have frequent infections but have suspected allergies to many antibiotics, leaving few options for treatment
Skin testing — Skin testing is the most reliable method to determine the risk of a serious allergic reaction in a person with a history of allergy to penicillin.
Several different types of penicillin preparations are required for skin testing; most people are allergic to the penicillin break-down products, produced after the drug has been digested. These break-down products can be manufactured commercially but are not currently available in the United States. Thus, skin testing cannot be performed in the United States at this time. It is hoped that the preparations will be available again within the next 12 to 24 months.
Testing procedure — Skin testing should be done by an allergist in an office setting. Testing usually takes three to four hours to complete. The skin is pricked with weak solutions of the various preparations of penicillin and observed for a reaction. If there is no skin reaction, slightly stronger solutions are then used. This is repeated until there is a skin reaction or the testing protocol is completed (with no reactions).
A positive skin reaction is an itchy, red lump that lasts about half an hour and then resolves. The testing is stopped if a skin reaction occurs since this indicates that the person is truly allergic.
If a patient completes the protocol without a positive reaction, a single oral dose of full strength penicillin is usually given. This confirms that the patient does not have an allergic reaction, and is done since there is a very small risk of false negative results (when the skin test is negative although the person is actually allergic).
Safety of skin testing — Skin testing is normally very safe. However, certain people should not have skin testing; a person who is severely allergic to penicillin could develop a dangerous whole-body or anaphylactic reaction. Skin testing is not generally done in people who have a strong history of severe allergy, especially if the reaction happened within the past year. In such patients, an alternate antibiotic should be used, or desensitization to penicillin should be performed if no alternates are acceptable or available. (See "Desensitization" below). Skin testing should not be done in people taking certain medications, such as beta-blockers (eg, atenolol, propranolol, nadolol, esmolol, carvedilol, metoprolol, and sotalol). These medications can interfere with treatment of a severe allergic reaction, were it to unexpectedly occur during testing. Finally, skin testing should not be done in patients with an extensive skin rash since it would be difficult to judge if skin test results were positive or negative.
Penicillin skin testing does not provide any information about certain types of reactions. In particular, a person who has experienced a severe reaction with extensive blistering and peeling of the skin (Stevens-Johnson syndrome or toxic epidermal necrolysis), a widespread sunburn-like reaction that later peeled (erythroderma), or a rash composed of small bulls-eyes or target-like spots (erythema multiforme), should not have skin testing. People with these types of reactions should never again be given the medication that caused the reaction. This applies to all situations since a second exposure could cause death.
Interpreting results — Medical tests, including skin testing, are rarely 100 percent accurate. Most people with a positive penicillin skin test will experience an allergic reaction if given penicillin or a related antibiotic (as would be expected). However, 3 percent of people with a history of penicillin allergy but negative skin tests will also experience an allergic reaction. These reactions are uniformly mild, and anaphylaxis in this situation has never been reported.
OTHER ANTIBIOTICS — Reliable skin tests are not commercially available for antibiotics other than penicillin. Thus, determining if a person has an allergy to other antibiotics is more difficult, and mostly based on the history of the reaction. Skin testing with other antibiotics is sometimes performed, but the results are much less certain than those of penicillin testing. In general, the suspicious drug should be avoided unless life-threatening infections demand their use. In the latter case, desensitization is necessary.
Cephalosporins — Cephalosporins are a class of antibiotics closely related to penicillin. There are a number of cephalosporin medications, a few of which include cephalexin (Keflex®), cefaclor (Ceclor®), cefuroxime (Ceftin®), cefadroxil (Duricef®) , cephadrine (Velocef®). cefprozil (Cefzil®), loracarbef (Lorabid®), ceftibuten (Cedax®), cefdinir (Omnicef®), cefditoren (Spectracef®), cefpodoxime (Vantin®) and cefixime (Suprax®).
People with a positive skin test to penicillin have a high risk of an allergic reaction to cephalosporins, compared to those who have a negative skin test. Those with a history of a cephalosporin allergy who require a cephalosporin should have a penicillin skin test, if available. If the test is negative, the patient should take penicillin (rather than a cephalosporin). If a cephalosporin is required or skin testing is not available, desensitization is recommended.
Monobactams — People who are allergic to penicillin can be given aztreonam (Azactam®), a monobactam, because no significant cross reactivity between penicillin and monobactams has been demonstrated.
Carbapenems — Imipenem and meropenem are carbapenem antibiotics that cross-react with penicillin. Thus, imipenem and meropenem should not be given to people who are allergic to penicillin unless they undergo desensitization. Carbapenems are only given by intravenous injection.
DESENSITIZATION — Desensitization can be done for people who are truly allergic to penicillin but require treatment with it or a closely related antibiotic. Desensitization refers to a process of giving a medication in a controlled and gradual manner, which allows the person to tolerate it temporarily without an allergic reaction.
Technique — Desensitization can be performed with oral or intravenous medications. There are different techniques for desensitization. Some patients undergo desensitization in an outpatient clinic under supervision while others are treated in an intensive care unit.
Limitations — While usually successful, desensitization has two important limitations. Desensitization does not work and must never be attempted for certain types of reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis, erythroderma, and erythema multiforme). (See "Safety of skin testing" above). Desensitization also does not work for other types of immunologic reactions to antibiotics, such as serum sickness, drug fever, or hemolytic anemia. Desensitization is temporary. Allergic reactions to the medication given during desensitization is unlikely as long as it is taken regularly. However, once the antibiotic is stopped for more than 24 hours (times differ slightly for different medications), the person is again at risk for a sudden allergic reaction. Repeat desensitization is required if the same medication is needed again.
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. American Academy of Allergy Asthma and Immunology
(www.aaaai.org)
National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
National Institute of Allergy and Infectious Diseases
(www.niaid.nih.gov)
The American Academy of Family Physicians
(familydoctor.org)
[1-3]
Patients who have a remote history of allergic reaction to a medication may become less allergic as time passes. Only about 20 percent of patients will be allergic to penicillin 20 years after their initial allergic reaction if they are not exposed to it again during this time period.
TYPES OF PENICILLIN ALLERGY — Several different symptoms may develop after taking penicillin that can indicate that an allergy is present. These include hives (raised, intensely itchy spots that come and go over hours), angioedema (swelling of the tissue under the skin), wheezing and coughing from bronchospasm (narrowing of the airways into the lungs), and anaphylaxis.
Anaphylaxis — Anaphylaxis is a sudden, potentially life-threatening allergic reaction. Symptoms can include very low blood pressure, hives, difficulty breathing, abdominal pain, swelling of the throat or tongue, and diarrhea. Two to 4 percent of allergic reactions to penicillin are of this type. (See "Patient information: Anaphylaxis").
Less severe allergic reactions — A person may develop only hives or only angioedema, without other symptoms, while taking penicillin. This can be a sign that the person is allergic. If they were to take the medicine again, they might develop a more severe reaction, even anaphylaxis.
Rashes — Several different types of rashes can appear while people are taking penicillin. Rashes that involve hives are most suggestive of a true allergy rather than another type of reaction to penicillin. However, some people, especially young children, can develop flat, itchy, speckled rashes that do not involve hives. This type of rash is less likely to indicate a dangerous allergy, although it can be difficult to distinguish between different types of rashes if they happened in the past. Taking a photograph of a rash to show to doctors later is always helpful.
Adverse reactions — Some people have unpleasant side effects (called adverse reactions) after taking penicillin or other antibiotics. Adverse reactions are more common than true allergies, and may include stomach upset or other gastrointestinal reactions. Adverse reactions are not related to allergic reactions, and it is important to distinguish between the two. Persons who incorrectly report that they have had an allergic reaction may then be treated for a particular infection with a less-effective antibiotic. This can lead to antibiotic failure or resistance, which can be costly and prolong illness.
When reporting past problems with antibiotics, it is important to provide as much detail as possible about the reaction. Patients who are uncertain if a past allergic reaction was truly caused by allergy should avoid the antibiotic.
DIAGNOSIS — In some situations, it is necessary to determine with certainty if a person is allergic to penicillin. Testing for allergy is recommended in the following situations: Persons who have a suspected penicillin (or closely related antibiotic) allergy and require penicillin to treat a life-threatening condition for which no alternate antibiotic is appropriate Patients who have frequent infections but have suspected allergies to many antibiotics, leaving few options for treatment
Skin testing — Skin testing is the most reliable method to determine the risk of a serious allergic reaction in a person with a history of allergy to penicillin.
Several different types of penicillin preparations are required for skin testing; most people are allergic to the penicillin break-down products, produced after the drug has been digested. These break-down products can be manufactured commercially but are not currently available in the United States. Thus, skin testing cannot be performed in the United States at this time. It is hoped that the preparations will be available again within the next 12 to 24 months.
Testing procedure — Skin testing should be done by an allergist in an office setting. Testing usually takes three to four hours to complete. The skin is pricked with weak solutions of the various preparations of penicillin and observed for a reaction. If there is no skin reaction, slightly stronger solutions are then used. This is repeated until there is a skin reaction or the testing protocol is completed (with no reactions).
A positive skin reaction is an itchy, red lump that lasts about half an hour and then resolves. The testing is stopped if a skin reaction occurs since this indicates that the person is truly allergic.
If a patient completes the protocol without a positive reaction, a single oral dose of full strength penicillin is usually given. This confirms that the patient does not have an allergic reaction, and is done since there is a very small risk of false negative results (when the skin test is negative although the person is actually allergic).
Safety of skin testing — Skin testing is normally very safe. However, certain people should not have skin testing; a person who is severely allergic to penicillin could develop a dangerous whole-body or anaphylactic reaction. Skin testing is not generally done in people who have a strong history of severe allergy, especially if the reaction happened within the past year. In such patients, an alternate antibiotic should be used, or desensitization to penicillin should be performed if no alternates are acceptable or available. (See "Desensitization" below). Skin testing should not be done in people taking certain medications, such as beta-blockers (eg, atenolol, propranolol, nadolol, esmolol, carvedilol, metoprolol, and sotalol). These medications can interfere with treatment of a severe allergic reaction, were it to unexpectedly occur during testing. Finally, skin testing should not be done in patients with an extensive skin rash since it would be difficult to judge if skin test results were positive or negative.
Penicillin skin testing does not provide any information about certain types of reactions. In particular, a person who has experienced a severe reaction with extensive blistering and peeling of the skin (Stevens-Johnson syndrome or toxic epidermal necrolysis), a widespread sunburn-like reaction that later peeled (erythroderma), or a rash composed of small bulls-eyes or target-like spots (erythema multiforme), should not have skin testing. People with these types of reactions should never again be given the medication that caused the reaction. This applies to all situations since a second exposure could cause death.
Interpreting results — Medical tests, including skin testing, are rarely 100 percent accurate. Most people with a positive penicillin skin test will experience an allergic reaction if given penicillin or a related antibiotic (as would be expected). However, 3 percent of people with a history of penicillin allergy but negative skin tests will also experience an allergic reaction. These reactions are uniformly mild, and anaphylaxis in this situation has never been reported.
OTHER ANTIBIOTICS — Reliable skin tests are not commercially available for antibiotics other than penicillin. Thus, determining if a person has an allergy to other antibiotics is more difficult, and mostly based on the history of the reaction. Skin testing with other antibiotics is sometimes performed, but the results are much less certain than those of penicillin testing. In general, the suspicious drug should be avoided unless life-threatening infections demand their use. In the latter case, desensitization is necessary.
Cephalosporins — Cephalosporins are a class of antibiotics closely related to penicillin. There are a number of cephalosporin medications, a few of which include cephalexin (Keflex®), cefaclor (Ceclor®), cefuroxime (Ceftin®), cefadroxil (Duricef®) , cephadrine (Velocef®). cefprozil (Cefzil®), loracarbef (Lorabid®), ceftibuten (Cedax®), cefdinir (Omnicef®), cefditoren (Spectracef®), cefpodoxime (Vantin®) and cefixime (Suprax®).
People with a positive skin test to penicillin have a high risk of an allergic reaction to cephalosporins, compared to those who have a negative skin test. Those with a history of a cephalosporin allergy who require a cephalosporin should have a penicillin skin test, if available. If the test is negative, the patient should take penicillin (rather than a cephalosporin). If a cephalosporin is required or skin testing is not available, desensitization is recommended.
Monobactams — People who are allergic to penicillin can be given aztreonam (Azactam®), a monobactam, because no significant cross reactivity between penicillin and monobactams has been demonstrated.
Carbapenems — Imipenem and meropenem are carbapenem antibiotics that cross-react with penicillin. Thus, imipenem and meropenem should not be given to people who are allergic to penicillin unless they undergo desensitization. Carbapenems are only given by intravenous injection.
DESENSITIZATION — Desensitization can be done for people who are truly allergic to penicillin but require treatment with it or a closely related antibiotic. Desensitization refers to a process of giving a medication in a controlled and gradual manner, which allows the person to tolerate it temporarily without an allergic reaction.
Technique — Desensitization can be performed with oral or intravenous medications. There are different techniques for desensitization. Some patients undergo desensitization in an outpatient clinic under supervision while others are treated in an intensive care unit.
Limitations — While usually successful, desensitization has two important limitations. Desensitization does not work and must never be attempted for certain types of reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis, erythroderma, and erythema multiforme). (See "Safety of skin testing" above). Desensitization also does not work for other types of immunologic reactions to antibiotics, such as serum sickness, drug fever, or hemolytic anemia. Desensitization is temporary. Allergic reactions to the medication given during desensitization is unlikely as long as it is taken regularly. However, once the antibiotic is stopped for more than 24 hours (times differ slightly for different medications), the person is again at risk for a sudden allergic reaction. Repeat desensitization is required if the same medication is needed again.
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. American Academy of Allergy Asthma and Immunology
(www.aaaai.org)
National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
National Institute of Allergy and Infectious Diseases
(www.niaid.nih.gov)
The American Academy of Family Physicians
(familydoctor.org)
[1-3]
Subscribe to:
Posts (Atom)