Rare allergic reaction to exercise

DEAR DR. ROACH » Please write about food-dependent exercise-induced anaphylaxis. Many medical professionals still do not know about this rare and potentially deadly condition. Thank you!

— M.S.

DEAR READER » Anaphylaxis is the most serious of all the allergic reactions. It is rapid in onset, and initially causes symptoms such as warmth and flushing, diffuse hives and itching, and sudden fatigue. More serious symptoms include swelling of the lips, tongue and uvula (that thing that hangs down in the back of the throat). This can be so serious that it restricts a person’s breathing. Gastrointestinal symptoms can occur, including nausea, cramping and diarrhea. Cardiovascular symptoms include low blood pressure, fainting and ultimately failure of the circulatory system. Anaphylaxis most often occurs after exposure to an allergen, especially drugs, but sometimes foods and insect stings as well.

Exercise-induced anaphylaxis is a rare form of anaphylaxis, more common in women. As its name states, the anaphylaxis is related to exercise and can begin at any stage of exercise. More intensive forms of exercise are more likely to cause symptoms.

Stopping exercise immediately usually stops the symptoms; however, many people instinctively run for help, which can dramatically worsen the attack. That’s the most important message about exercise-induced anaphylaxis. Food-dependent exerciseinduced anaphylaxis is an even rarer subtype of exercise-induced anaphylaxis. In this condition, exerciseinduced anaphylaxis occurs only if exercise begins within minutes or hours of eating a specific food, although rarely, symptoms can occur if a person eats the food immediately after exercising. The most commonly implicated foods are grains (especially wheat) and nuts, but many foods have been reported, including fruits, vegetables, legumes and seeds.

The diagnosis should be suspected in any person who develops severe allergic symptoms after exercise. You are quite right that this is not a wellknown condition, and referral to an expert, such as an allergist, is appropriate when the diagnosis is suspected. The allergist may do laboratory testing and skin testing for allergies to help confirm the diagnosis. An exercise challenge test is performed by some experts, only if they have the expertise and tools necessary to deal with anaphylaxis should it occur.

DEAR DR. ROACH » I have had an “abnormal” result for atrial fibrillation from a commercial screening test. I do not presently have a primary care doctor. Could you advise how/ where to start?

— D.S.

DEAR READER » Screening tests are not very accurate at diagnosing atrial fibrillation, which is an abnormal heart rhythm that puts people at increased risk for stroke. However, when a screening test is positive, it is certainly appropriate to get further input.

Although there have been technical advances on wearable devices, the best way of diagnosing atrial fibrillation remains a medically performed and physician-interpreted EKG. A simple office EKG is accurate at diagnosing a person who is in atrial fibrillation at the time, but some people go in and out of atrial fibrillation. In that case, a medical device can be worn for a period of time, usually 48 hours or longer, to identify atrial fibrillation. A primary care doctor or a cardiologist would usually order this test.

I hope you are able to connect with a primary care doctor soon, as the care should be better and less expensive than visiting an emergency room.