Exercise-Induced Anaphylaxis

In the last article, we understood that exercise could make asthma worse in some persons. In this article, we will see how exercise could be associated with hives and anaphylaxis. Anaphylaxis is an extreme allergic reaction affecting the whole body. Exercise-induced anaphylaxis was first described in some accomplished athletes. The following exercise, some of these athletes experienced full body itching, hives, swelling, wheezing and drop in blood pressure. To make it more confusing, these athletes did not experience anaphylaxis every time they exercised. Most of these people were highly allergic to environmental allergens such as pollen. However, exercising indoors did not prevent these reactions from happening. It is clear that exercise is associated with the release of histamine from mast cells in the body where it is typically stored. How exercise makes, the release of histamine possible is not clear. It is not due to increasing body heat during exercise.

Foods could make it worse

There is another condition closely related to exercise-induced anaphylaxis. It is known as Food-dependent exercise-induced anaphylaxis. In this unusual condition, persons who are prone to it experience anaphylaxis only when they exercise within 4-6 hours after eating. These people can exercise without any problem if they forego eating for four to six hours before exercise. In some individuals with this condition only certain foods will cause this issue. In others, any food can do this. Commonly implicated foods are wheat, milk, celery, fish, shrimp, etc. Interestingly eating these foods in the absence of exercise does not cause any problems in these individuals. Again these episodes are not consistent- meaning anaphylaxis does not happen every time they eat and exercise. For this reason, the diagnosis could be delayed. There are other triggers besides foods that could be associated with this condition. They include alcohol, aspirin and NSAIDs and menstrual periods in women.

How do you diagnose exercise-induced anaphylaxis?

It is important that people be aware of this condition. Otherwise, unnecessary investigations could be done. Diagnosis is by taking real history and by ruling out other causes. For example, people with heart and lung diseases could have exercise-induced symptoms. Similarly hypoglycemia (low blood sugar) could be aggravated by exercise especially when one foregoes a meal before exercise. Allergic reactions from exposure to extreme amounts of pollen during spring and fall and insect stings could cause anaphylaxis without any bearing on activity. Lack of physical fitness can cause symptoms the following exercise. Vasovagal reactions can present with blackouts, sweating, and nausea. Exercise-induced anaphylaxis is best diagnosed by physicians who are trained in diagnosing and treating anaphylaxis. Patients can be made to exercise under controlled conditions with proper medical supervision with and without implicated foods to diagnose the condition. These procedures are not without risk. Food allergy can be ruled out by doing allergy skin or blood tests.

What can you do about it?

If you have exercise-induced anaphylaxis, it is best to avoid extreme exertion. Walking as a form of exercise can be an option. You should wear a MedicAlert bracelet and carry two epinephrine self-injectors. You should have a companion with you when you exercise, and he or she should know about your condition and be trained in the administration of epinephrine if required. If food plays any role in your situation, it is best not to eat any food for four hours before you undertake the exercise. You should use epinephrine immediately and call 911 if you experience anaphylactic symptoms. It is best not to exercise in cold weather and not to drink alcohol or take aspirin and NSAIDs before exercise. Women should avoid activities when they are menstruating. Remember anaphylaxis could end fatally.