Exercise

Abstract

The nature of systemic reactions to exercise can often be deciphered with a careful clinical history. Important parameters include the size of urticarial lesions, the nature of airway obstruction, the development of hypotension, precipitating factors other than exercise, and reproducibility under similar conditions. In equivocal cases, a passive heat challenge is a specific test for cholinergic urticaria. Although an exercise challenge may demonstrate the diagnosis of exercise anaphylaxis, such testing can be dangerous and unfortunately has poor sensitivity. The diagnostic value of methacholine or codeine skin testing remains controversial. Cholinergic urticaria generally responds well to H1 antihistamines and particularly to agents such as hydroxyzine, which have significant anticholinergic activity. Other useful modalities include an exercise program with gradual increases in duration and intensity of exercise and minimizing any exposures that might cause undue prolonged passive warming. Exercise anaphylaxis is managed by early recognition of systemic symptoms and prompt cessation of exercise and administration of subcutaneous epinephrine. General measures that also help reduce the frequency and intensity of attacks include not exercising for several hours after eating; avoidance of aspirin, other nonsteroidal anti-inflammatory drugs, and β-blockers prior to exercise; and for women, avoidance of exercise around the time of menses. In selected patients, pre-exercise treatment with antihistamines or inhaled or oral cromolyn sodium may decrease the likelihood of a systemic reaction to exercise.