PHYSICAL ALLERGIES AND EXERCISE - CLINICAL IMPLICATIONS FOR THOSE ENGAGED IN SPORTS ACTIVITIES

There are several allergic responses that may occur in susceptible ind ividuals as a result of exposure to physical stimuli. Most of these co nditions are mediated by vasoactive substances and usually result in s ymptoms of urticaria and/or angioedema. There are 2 such conditions th at may occur as a direct result from exercise. The first of these is c holinergic urticaria. Patients with cholinergic urticaria experience p unctate (2 to 4 mm) hives which occur reproducibly with exercise or wi th passive warming, such as might occur in a steam bath or hot pool. L ife-threatening hypotension or angioedema usually do not occur with ch olinergic urticaria. This condition usually responds well to oral hydr oxyzine. Exercise-induced anaphylaxis (EIA) is a form of physical alle rgy that has been recognised with increasing frequency in recent years . This syndrome typically presents with generalised pruritus, a flushi ng sensation, a feeling of warmth and the development of conventional (10 to 15 mm) urticaria in association with vigorous physical exertion only. Symptoms tend to occur variably with exposure to exercise and d o not typically occur with passive warming. During symptomatic attacks , cutaneous mast cells degranulate and serum histamine levels increase . Treatment is problematic. Cessation of exercise with onset of sympto ms and self-administration of epinephrine (adrenaline) are recommended . Other physical allergies that may affect exercising individuals incl ude cold urticaria, localised heat urticaria, symptomatic dermatograph ism dermographism), delayed pressure urticaria (angioedema), solar urt icaria and aquagenic urticaria. Management of these conditions may inc lude patient education, selective avoidance, antihistamines and, in so me cases, induction of tolerance.