Exercise can induce allergies – exercise-induced anaphylaxis
Exercise Can Induce Allergies
A 22-year-old medical student collapses during his usual 4-mile run. He is found by the side of the road and rushed to a nearby hospital. A deputy sheriff in his 40s works at his desk for an hour after eating lunch, then joins recruits on their conditioning run. Overcome by unbearable itching after jogging a mile, he returns to the locker room for an antihistamine and a cold shower. There he slumps to the floor and loses consciousness.
Until recently, symptoms like these were puzzling to doctors. But now the syndrome has a name – exercise-induced anaphylaxis or E.I.A. in medical parlance – and is recognized as a clinically distinct, possibly life-threatening form of allergic reaction.
Exercise-induced anaphylaxis is so named because of its striking similarity to anaphylactic reaction caused by foods, drugs, and insect stings, but usually none of the typical allergy-causing substances is involved. Its prevalence has undoubtedly been underestimated, and more cases are likely to turn up with the increased emphasis on physical fitness in our society.
Dr. Albert Sheffer, clinical professor of medicine at Harvard University Medical School, saw his first patient with an anaphylactic reaction to exercise in 1969, and several more patients were referred to him over the next few years. Intrigued by their unique symptoms, he decided to study and report on the phenomenon.
He found that episodes of E.I.A., which last from 30 minutes to four hours, usually begin with itching and hives, the hallmark of the syndrome, and progress to swelling of hands, feet, and face. In severe cases the victims experience difficulty breathing, confusion, loss of consciousness, and abnormally low blood pressure. Some report stomach cramps, diarrhea, vomitting, and headaches that last as long as 72 hours.
Another hallmark of E.I.A. is its unpredictability. One of the most disturbing variables, says Dr. Sheffer, is that the reactions do not occur every time the susceptible person exercises. The occurrence and severity of the reactions are unrelated to the type of exercise or how strenuous the workouts are, and they have been precipitated by a wide range of activities – from jogging short distances to running marathons, tennis warmups, strenous basketball and soccer, and even dancing.
To further complicate E.I.A. researchers’ task of identifying the syndrome and its cases, symptoms are difficult to reproduce in laboratory experiments even when victims are challenged with exercise programs identical to those that precipitated episodes, and symptoms are similar to other allergic reactions that occur during exercise like cholinergic urticaria and exercise-induced asthma. But E.I.A. is clinically separate from both: cholinergic urticaria is characterized by warmth, itching, and hives but rarely difficulty breathing, whereas asthma is characterized by wheezing and shortness of breath without itching and hives.
According to Dr. Ron Simon of the allergy and immunology department of Scripps Clinic and Research Foundation in San Diego, “Cholinergic urticaria happens when the victims goes over the peak of conditioning and becomes overheated, while E.I.A. usually occurs on the way up to the peak, during the first half of a workout, not during the last gasp.”
So far, researchers have been successful in identifying two distinct sub-types of E.I.A.: food-related and drug-related anaphylactic reactions. According to Dr. Sheffer, who now has data on over 500 patients, the foods and medications most often associated with E.I.A. are oranges, peaches, pineapple, bananas, shellfish, celery, and aspirin.
In one reported case, a 24-year-old woman experienced several reactions while jogging or dancing, but only after eating peaches. When she fasts for more than two hours before exercising, she is free of symptoms.
So far, both treatment and prevention of exercise-induced anaphylaxis are limited to stopping the workouts as soon as preliminary symptoms appear, like itching or hives, and administering drugs if the victim has difficulty breathing or collapses.
People who have suffered E.I.A. episodes need not give up their otherwise healthy habit of exercising if they take certain precautions:
– Stop exercising at the first sign of symptoms and until
symptoms disappear completely;
– Use the buddy system whenever exercising, and make sure
the buddy knows how to administer adrenalin; and
– Avoid any identified aggravating factors, like eating less than
two to four hours before exercising or taking aspirin less than
six hours before exercising.
“Most people have the advance symptom, the preceding itch, and they will be fine if they stop exercising at that first sign,” says Dr. Simon. “But if they ignore the warnings and go on, they risk a serious, possibly life-threatening anaphylactic reaction. When the itch goes away, it is usually possible to go right back to the workout with no problem.”
COPYRIGHT 1989 Vegetus Publications
COPYRIGHT 2004 Gale Group