Exercise-induced urticaria, angioedema, and anaphylactoid episodes.

Six subjects with exercise-induced anaphylactoid symptoms were evaluated by exercise challenge. Five of the six patients developed symptoms during free running. One subject developed only periorbital angioedema; another developed giant urticaria, wheeze, and hypotension; and three subjects developed cholinergic urticaria. One of the subjects with cholinergic urticaria also became hypotensive. Both of the subjects who developed hypotension also exhibited elevations in plasma histamine (11.2 and 23.2 ng/ml). Subjects who exhibited only cutaneous or subcutaneous manifestations failed to develop elevated levels of plasma histamine. Serum complement determinations (C'3, C'4) remained normal in all subjects at all time intervals. Thus exercise-induced anaphylactoid reactions can appear with a variety of cutaneous manifestations, including angioedema only, giant urticaria, and cholinergic urticaria. Elevated levels of plasma histamine are found only when systemic symptoms such as hypotension occur concomitantly.