Exercise Induced Anaphylaxis
Exercise-induced anaphylaxis (EIA) is a rare disorder in which anaphylaxis occurs after physical activity. The symptoms may include pruritus, hives, flushing, wheezing, and GI involvement, including nausea, abdominal cramping, and diarrhea. If physical activity continues, patients may progress to more severe symptoms, including angioedema, laryngeal edema, hypotension, and, ultimately, cardiovascular collapse. Cessation of physical activity usually results in immediate improvement of symptoms. Four phases in the sequence of the anaphylaxis attack—prodromal, early, fully established, and late—have been defined. Prodromal symptoms included a feeling of fatigue, generalized warmth and pruritus with erythema or “redness of the skin”. The early phase featured generalized urticaria.
Vigorous forms of physical activity such as jogging, tennis, dancing, and bicycling are more commonly associated with exercise-induced anaphylaxis, although lower levels of exertion (eg, walking and yard work) are also capable of triggering attacks. Other reports have implicated running, soccer, raking leaves, shoveling snow, and horseback riding.
Exercise-induced anaphylaxis attacks are not consistently elicited by the same type and intensity of physical activity in a given patient. Co-factors such as foods, alcohol, temperature, drugs (eg, aspirin and other nonsteroidal anti-inflammatory drugs), humidity, seasonal changes, and hormonal changes are important in the precipitation of attacks.
A distinct subset of exercise-induced anaphylaxis is food-dependent exercise-induced anaphylaxis (FDEIA), in which anaphylaxis develops only if physical activity occurs within a few hours after eating a specific food. Neither food intake nor physical activity by itself produces anaphylaxis.
The foods most commonly implicated in food-dependent exercise-induced anaphylaxis are wheat, shellfish, tomatoes, peanuts, and corn. However, the disorder has been reported with a wide variety of foods, including fruits, seeds, milk, soybean, lettuce, peas, beans, rice, and various meats.
Inhalant allergens and upper respiratory infections have also been implicated in exercise-induced anaphylaxis. I had one patient with significant environmental allergies and asthma. She would experience exercise induced anaphylaxis for a few months after having an upper respiratory of sinus infection.
Prevention remains the best treatment for patients with exercise-induced anaphylaxis (see Treatment and Management). Reducing physical activity to a lower level may diminish the frequency of attacks. In patients whose attacks are associated with ingestion of food, avoiding the offending food for 12 hours prior to exercise is essential. If no offending food is known, then the patient should avoid eating any food 6-8 hours prior to exercise. Patients should avoid exercise in extremely humid, hot, or cold weather and during the allergy season.
Patients should be instructed on the proper use of emergency injectable epinephrine (Adrenaclick, EpiPen, Twinject) and have one available at all times. Patients should wear a medical alert bracelet with instructions on the use of epinephrine.