UPDATE ON EXERCISE-INDUCED ASTHMA

Exercise-induced asthma (EIA) is a temporary increase in airway resist ance that occurs after several minutes of strenuous exercise, generall y eight to 15 minutes after the patient has stopped exercising. Some i ndividuals experience a secondary reduction in pulmonary function seve ral hours later, the so-called late-phase response. Many physicians be lieve that EIA is caused by respiratory water loss or airway cooling. Others incriminate tissue mast cells of the lung. The role of histamin e is uncertain because it is detected inconsistently in the serum afte r an attack. Recent studies suggest that the release of sulfidopeptide leukotrienes may play a major role in EIA. Although the exact pathoph ysiology has yet to be determined, several highly successful treatment regimens have been developed. Preventive pharmacologic treatment with aerosolized beta-agonists is more successful than treatment with crom olyn sodium; however, coadministration of these agents produces signif icant symptomatic improvement in more than 90% of patients. Other usef ul medications include antihistamines, anticholinergic agents, theophy lline, oral beta-agonists, calcium channel blockers, alpha-adrenergic antagonists, nedocromil, and leukotriene antagonists. Exercise-induced asthma may be suppressed with warm humidified air. This environment c an be simulated by swimming in a heated pool or wearing a scarf over t he nose and mouth in cold weather.