In the last article, we discussed how exercise could make asthma worse in some people. 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 atheletes. Following exercise, some of these atheletes experienced whole-body itching, hives, swelling, wheezing and drop in blood pressure. These atheletes did not experience anaphylaxis every time they exercised.
Most of these people were highly allergic to environmental allergens such as pollen. But exercising indoors did not prevent these reactions from happening. It is clear that exercise is associated with release of histamine from mast cells in the body where it is stored normally. How exercise makes the release of histamine possible is not clear. It is not due to the increase in body heat from 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 interesting 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 people with this condition, only certain foods will cause this problem. 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 which could be associated with it. They include alcohol, aspirin and NSAIDs, and menstrual periods in women.
How do you
It is important that people are aware of this condition. Otherwise, unnecessary investigations may be done. Diagnosis is obtained by taking a good history and by ruling out other causes of anaphylaxis. 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 from insect stings could cause anaphylaxis without any bearing on exercise. Lack of physical fitness can cause symptoms 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 and other allergic causes 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 condition, it is best not to eat any food for four to six hours before you undertake exercise. You should use epinephrine immediately and call 911 if you experience anaphylactic symptoms. It is best not to exercise in cold weather, and don't drink alcohol or take aspirin and NSAIDs before exercise. Women should avoid exercises when they are menstruating. Remember anaphylaxis could end fatally.
Natarajan Asokan, M.D., is a board-certified allergist and immunologist. He can be reached at 1739 Beverly Ave, Suite 118, Kingman, AZ 86409, or call (928) 681-5800.