Physical allergies.

Allergic responses that occur as a result of exposure to physical stimuli are discussed. Most of these conditions are mediated by vasoactive substances, resulting in urticaria and/or angioedema. Susceptible individuals who engage in athletic activities may place themselves at particular risk for these problems. The physical allergies include cholinergic urticaria, exercise-induced anaphylaxis, cold urticaria, dermatographism, solar urticaria, and aquagenic urticaria. Management of these conditions includes patient education, selective avoidance, antihistamines, and, in some cases, induction of tolerance.