Exercise-induced anaphylaxis is a condition that was first described in 1980. People with this condition experience hives, itching, shortness of breath, and low blood pressure 5 to 30 minutes after the onset of exercise. These symptoms can progress to shock and even death. Jogging is the most common type of exercise that causes exercise-induced anaphylaxis.
People with exercise-induced anaphylaxis do not get these symptoms after a hot shower, fever, or with anxiety. This differentiates exercise-induced anaphylaxis from cholinergic urticaria.
Exercise-induced anaphylaxis sometimes occurs only when someone exercises within 30 minutes of eating certain foods such as wheat and shellfish. For these people, exercising alone or eating the offending food without exercising produces no symptoms.
Exercise-induced anaphylaxis can be diagnosed by having the patient exercise and observing the symptoms that develop. This method must be used with caution and only in a setting with the appropriate resuscitative measures available. Exercise-induced anaphylaxis can be distinguished from cholinergic urticaria by the hot water immersion test. In this test the patient is immersed in a bath of water at 43 degrees Celsius. Someone with exercise-induced anaphylaxis will not develop hives, whereas a person with cholinergic urticaria will develop the characteristic small hives especially on the neck and chest.
The immediate symptoms of exercise-induced anaphylaxis are treated with antihistamines, epinephrine, and airway support. Taking antihistamines prior to exercise may be effective. A medication called ketotifen stabilizes mast cells and prevents histamine release, and has been effective in treating this disorder. Avoiding exercise or foods that cause symptoms is important. In some settings, tolerance can be induced by regular exercise, but this must be under close medical supervision.