Exercise induced asthma: response to disodium cromoglycate in skin‐test positive and skin‐test negative subjects

Summary Thirty‐nine asthmatic subjects, aged 5‐50 and each with a history of exercise‐induced asthma, were classified according to their skin response to prick tests using nineteen common antigens. Ten had negative skin tests, four responded only to D. farinae and twenty‐five had multiple positive responses. Each patient then carried out three exercise tests on a treadmill, each test on a separate day. A control test was followed, in random order, by an exercise test after administration of disodium cromoglycate or of a placebo. In all groups, the mean fall in peak expiratory flow rate was less after disodium cromoglycate than after placebo, but the difference was significant only for the skin‐test positive groups. Similarly, positive skin‐test groups had a higher incidence of drug responders than did the negative skin‐test group. These observations are discussed.