Exercise-induced anaphylaxis and urticaria.

In a select group of persons, exercise can produce a spectrum of allergic s ymptoms ranging from an erythematous, irritating skin eruption to a life-th reatening anaphylactic reaction. The differential diagnosis in persons with exercise-induced dermatologic and systemic symptoms should include exercis e-induced anaphylaxis and cholinergic urticaria. Both are classified as phy sical allergies. Mast cell degranulation with the release of vasoactive sub stances appears to be an inciting factor for the production of symptoms in both cases. Exercise-induced anaphylaxis and cholinergic urticaria can be d ifferentiated on the basis of urticarial morphology, reproducibility, progr ession to anaphylaxis and response to passive warning. Diagnosis is usually based on a thorough history and examination of the morphology of the lesio ns. Management of acute episodes of exercise-induced anaphylaxis includes c essation of exercise, administration of epinephrine and antihistamines, vas cular support and airway maintenance. Long-term care may require modificati on of or abstinence from exercise, avoidance of co-precipitating factors an d the prophylactic use of medications such as antihistamines and mast cell stabilizers.