Identifying exercise allergies: exercise-induced anaphylaxis and cholinergic urticaria.

Exercise-related allergies vary from the benign rash of cholinergic urticaria to life-threatening exercise-induced anaphylaxis. Rapid diagnosis is essential, but it can be difficult to tell the two conditions apart. The size of the wheals and the patient history provide the best clues. Giving epinephrine and taking steps to protect the patient's airway, breathing, and circulation are standard treatment for exercise-induced anaphylaxis. Effective management for less severe cases involves exercising with a partner, keeping self-injectable epinephrine on hand, and avoiding exercise before and after meals. Prophylactic antihistamines are more effective for cholinergic urticaria than for exercise-induced anaphylaxis.