Exercise-induced anaphylaxis and urticaria.

In a select group of persons, exercise can produce a spectrum of allergic symptoms ranging from an erythematous, irritating skin eruption to a life-threatening anaphylactic reaction. The differential diagnosis in persons with exercise-induced dermatologic and systemic symptoms should include exercise-induced anaphylaxis and cholinergic urticaria. Both are classified as physical allergies. Mast cell degranulation with the release of vasoactive substances appears to be an inciting factor for the production of symptoms in both cases. Exercise-induced anaphylaxis and cholinergic urticaria can be differentiated on the basis of urticarial morphology, reproducibility, progression to anaphylaxis and response to passive warming. Diagnosis is usually based on a thorough history and examination of the morphology of the lesions. Management of acute episodes of exercise-induced anaphylaxis includes cessation of exercise, administration of epinephrine and antihistamines, vascular support and airway maintenance. Long-term care may require modification of or abstinence from exercise, avoidance of co-precipitating factors and the prophylactic use of medications such as antihistamines and mast cell stabilizers.