(Anaphylactic Reaction; Severe Allergic Reaction)
Anaphylaxis is a severe, sometimes life-threatening, allergic reaction. It affects multiple organs, including the heart and lungs.
It is important to seek medical care right away if you have symptoms of anaphylaxis.
Substances that cause anaphylaxis are often called allergens or triggers. Common triggers include:
- Foods and food additives, especially eggs, peanuts, seafood, cow's milk, soy, fish, shellfish, seeds, and tree nuts
- Insect stings or bites from bees, wasps, hornets, yellow jackets, and fire ants
- Medicines (such as antibiotics, seizure medications, muscle relaxants)
- Latex products (such as gloves, medical tubing, condoms)
- Blood transfusion
- Some pain medicines, especially narcotics
Allergic Reaction to Medication (Hives)
Some triggers, like dyes used in x-ray procedures, can cause a reaction similar to anaphylaxis.
These factors increase your chance of developing anaphylaxis. Anyone can have anaphylaxis. Tell your doctor if you have any of these risk factors:
- Previous allergic reaction to the substances listed above, even if it is a mild reaction
- History of eczema, hay fever, or asthma
- Children who have certain conditions, such as spina bifida and urogenital defects may be at increased risk for latex allergy (because of heavy exposure to latex during multiple surgeries)
The symptoms of anaphylaxis usually occur within minutes after exposure to an allergen, but can occur hours later. Symptoms may be mild or very severe, including death. They include:
- Hives and itching
- Warmth or redness of skin
- Swelling, redness, stinging or burning, especially on the face, mouth, eyes, or hands
- Lightheadedness, pale/blue skin color, low pulse, dizziness
- Obstruction of the nose, mouth, and throat
- Severe respiratory distress (such as chest tightness, shortness of breath, wheezing)
- Nausea, vomiting, cramping, diarrhea, or abdominal pain
- Heart arrhythmias
- Low blood pressure
- Feelings of anxiety
The doctor will suspect anaphylaxis if you have symptoms and have been exposed to a likely allergen. It is also important to follow up with a doctor who specializes in allergies (allergist/immunologist). The diagnosis of allergy with a risk of anaphylactic reactions is made based on the patient’s history. It is confirmed with skin tests and sometimes blood tests done by allergy specialists.
Anaphylaxis is a medical emergency that requires immediate medical treatment, including:
- Epinephrine (adrenaline) injection—makes blood vessels constrict, relaxes the airway, stops itching and hives, and relieves gastrointestinal cramping
- Other medicines—corticosteroids and/or antihistamines may be given after the epinephrine to decrease inflammation and improve breathing.
- Bronchodilators—to improve breathing
- IV fluids—to maintain blood pressure
- Cardiopulmonary resuscitation (CPR)—may be necessary in severe cases when anaphylaxis leads to cardiovascular collapse. Severe anaphylaxis may require mechanical ventilation until swelling is brought under control.
NOTE: If you receive emergency epinephrine, you should go to the emergency room right away, even if your symptoms have gone away.
If you are diagnosed with anaphylaxis, follow your doctor's instructions.
Avoiding substances that trigger anaphylaxis is the best prevention. In addition:
- Allergy shots can decrease the risk of anaphylaxis and reduce the severity of the reactions to certain triggers.
- Wear a medical alert bracelet that lists your allergies.
- Tell your doctor or dentist about your allergies before taking any medicine. When possible, ask that medicines be taken as a pill. Allergic reactions can be more severe with injected medicines.
- Your doctor may give you self-injectable epinephrine kit to keep with you at home, work, in the car, and when you travel. Be sure family and friends know how to use the kit too. Get training from your doctor and practice using it in the doctor's office.
- Make sure your epinephrine kit is not expired.
- Make sure the school nurse and teachers know about any allergies your child has. If your child has self-injectable epinephrine, make sure school staff knows how to use it and understand when it is needed.
- If you are allergic to insect stings, wear protective clothing when outside.
- Always remain in the doctor or dentist's office 30 minutes after you have an injection. Report any symptoms right away.
American Academy of Allergy, Asthma, and Immunology
The Food Allergy and Anaphylaxis Network
Allergy Asthma Information Association
Calgary Allergy Network
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Last reviewed September 2013 by Marcin Chwistek, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.