Severity of asthma in skin test-negative and skin test-positive patients.

The standardized records of 144 asthmatic patients have been analyzed to determine whether the severity of their condition was correlated with the presence or absence of positive intradermal skin test reactions to a panel of seven allergen extracts (dust, feathers, Alternaria, Hormodendrum, mixed tree pollen, mixed grass pollen, and ragweed pollen). The skin tests were totally negative in 71 of the subjects, whereas in 73 subjects there was a strongly positive response to two or more allergens. The skin test-negative patients were older than the skin test-positive ones and had a shorter duration as well as a later onset of asthma. Also, they had lower serum-IgE levels and a lower frequency of a family history of atopic disease. Moreover, the skin test-negative group lost more time from their normal activities, required more visits to their doctor as a result of asthma, and were more frequently treated with oral corticosteroids. They additionally had greater air trapping on pulmonary function tests. However, when the groups were adjusted for the discordance in their age and duration of asthma, they tended to converge in the level of the variables that described the severity of their asthma. Thus the severity of asthma was found to be relatively similar in skin test-negative and skin test-positive patients.