Exercise-induced anaphylaxis (EIAn) is a rare condition in which anaphylactic reactions are triggered by exercise or physical exertion.
Jogging, tennis, dancing, and cycling are often associated with EIAn, though everyday activities like walking and yard work can also trigger episodes. According to a long-term study cited by Dr. Peter N. Huynh in an article on Medscape, “The physical activity most often associated with exercise-induced anaphylaxis was jogging. Other reports have implicated running, soccer, raking leaves, shoveling snow, and horseback riding.”
As Dr. Huynh states, EIAn attacks aren’t consistently triggered by the same type or intensity of activity, and can vary based on the consumption of foods, alcohol, or medications (particularly aspirin and other non-steroidal anti-inflammatory drugs), as well as hormonal changes, humidity, temperature and seasonal changes.
A factsheet from the Anaphylaxis Campaign in the UK says that mild symptoms of EIAn can include widespread flushing of the skin, hives, swelling of the skin anywhere on the body, swelling of the lips, abdominal pain, nausea, and vomiting.
More severe symptoms include swollen tongue, hoarse voice, difficulty swallowing, noisy breathing, wheezing, persistent cough, and feeling faint or weak.
To confuse an already perplexing condition, there is a separate subtype of EIAn known as food-dependent EIAn, which only occurs if physical exertion occurs within several hours of consuming a specific food or combination of foods. In this condition, neither eating the food(s) alone nor exercising alone will trigger anaphylaxis. Only in combination do attacks occur.
Foods often associated with the food-dependent subtype are wheat, shellfish, tomatoes, peanuts, and corn, says Dr. Huynh, though fruits, seeds, milk, soybean, lettuce, peas, beans, rice, and various meats are also known to have been involved in some reactions.
Because EIAn and its food-dependent variant have only been recognized within the last thirty years, much about them remains unknown. It’s not yet clear whether they’re lifelong conditions or whether some sufferers eventually outgrow them.
Diagnosing and managing EIAn and food-dependent EIAn
- Don’t self-diagnose. See your doctor and ask for a referral to an allergist.
- Once diagnosed, always carry your epinephrine auto-injector.
- Don’t exercise alone if you don’t know what triggers your reactions, and inform your exercise partners about your prescribed treatment.
- With food dependent exercise induced anaphylaxis, avoid trigger foods and medications on days you plan to exercise. If you forget, postpone your exercise for at least 24 hours.
- If symptoms occur, stop exercising or exerting yourself and rest immediately. Do not drive.
Tips adapted from Fact sheet – Exercise Induced Anaphylaxis, courtesy of Anaphylaxis Campaign, UK.
To read about EIAn and other non-food triggers of anaphylaxis, visit the non-food allergens section on foodallergycanada.ca or click here.