What is exercise-induced anaphylaxis?
Exercise-induced hives, non-itchy swelling, and anaphylaxis are rare forms of anaphylaxis brought on by vigorous exercise. During the course of exercising, affected people will develop generalized itching of the skin that progresses to generalized redness of the skin and hives. The condition rarely will progress to more severe symptoms of anaphylaxis, with tightness of the throat, wheezing, a drop in blood pressure (shock), and loss of consciousness.
What is food-dependent exercise-induced anaphylaxis?
An even less common disorder is food-dependent exercise-induced anaphylaxis, which occurs only when the affected person eats a specific food and exercises. This very rare form of anaphylaxis occurs only when the patient exercises within three to four hours of ingesting a food. When the individual ingests the food without exercising, or when he or she exercises without eating the specific food within the past three to four hours, no reaction occurs.
In the past two decades, instances of food-dependent exercise-induced anaphylaxis appear to be more common, possibly because of the increased popularity of physical training and exercising. Two forms of food-dependent exercise-induced anaphylaxis have been described: by far the most common involves reactions following the ingestion of a specific food; very rarely, reactions follow the ingestion of any food.
Patients with food-dependent exercise-induced anaphylaxis generally have asthma and other allergic disorders. Those with the specific form generally have a positive prick skin test to the food that provokes symptoms. Sometimes they have a history of reacting to the food when they were younger. This disorder appears to be twice as common in females as in males, and more common in the late teens to 30s.
Interestingly, the menstrual cycle appears to influence the development of symptoms in food-dependent exercise-induced anaphylaxis in women, with symptoms reportedly most pronounced just before menstruation. It has also been suggested that aspirin and hot weather may contribute to the development of anaphylaxis, but further research needs to be done to prove this conclusively.
The exact mechanism(s) involved in this disorder is unknown. Foods that have been reported to cause food-dependent exercise-induced anaphylaxis include wheat, shellfish, fruit, milk, celery, and fish, although any food may be a potential culprit.
How do I know if I have food-dependent exercise-induced anaphylaxis?
If you suspect that you might have any form of exercise-induced anaphylaxis, talk to your doctor. It’s important not to try to diagnose yourself.
Whether people "outgrow" this disorder is not known. While it is potentially life-threatening, appropriate identification of the responsible food, and careful avoidance, should allow affected athletes to participate in sports.
Hugh A. Sampson, MD, is professor of pediatrics and head of the Jaffe Food Allergy Institute at Mount Sinai Medical Center in New York City. He is also director of FAAN’s Medical Advisory Board.
This article is adapted from the February/March 1996 issue of Food Allergy News.
Want to know more about food-dependent exercise-induced anaphylaxis?
Read Laura's story about what it was like to be diagnosed with exercise-induced anaphylaxis.