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.