Exercise-induced anaphylaxis as a manifestation of cholinergic urticaria.

Two patients presented with a history of exercise-induced hypotension associated with severe pruritus and either generalized urticaria or facial angioedema. Each patient was exercised under controlled conditions with use of bicycle ergometer exerciser (900 KPM/min) for 20 to 30 min at 23 degrees C. Each patients complained of generalized pruritus and then erupted in lesions typical of cholinergic urticaria. In one patient the lesions became confluent about the face and were followed by eyelid edema, lip swelling, and transient hypotension. Plasma histamine levels were elevated in each patient and reached a maximal level between 20 and 25 min. Neither patient had a change in forced expiratory volume in one second during the episode and detailed pulmonary function testing in one patient revealed no change in airway resistance, specific conductance, forced expiratory vital capacity, or forced expiratory flow rates. One patient had a positive methacholine chloride (Mecholyl) skin test with satellite lesions, and the second patient was skin-test negative. The skin test-positive patient, who was not hypotensive when initially challenged, was strenuously exercised for 15 min/day. Progressively less severe reactions were seen associated with diminished histamine release, and the patient is now on a daily exercise program; symptoms in the second patient are controlled with hydroxazine. Our results indicate that some patients with the exercise-induced anaphylactic syndrome are unusual examples of severe cholinergic urticaria. Furthermore, the utility of a regular exercise program as part of the management of some patients with cholinergic urticaria requires further investigation.