Wheezing in school children is not always asthma

Our objective was to study whether children with reported asthma differed f rom children with wheeze but without asthma, and from children with neither asthma nor wheeze, regarding lung function, bronchial hyper-responsiveness (BHR) using methacholine inhalation, exercise-induced bronchoconstriction (EIB), and skin prick test (SPT) reactivity. School children (n=2188), enro lled in a survey of asthma, were classified into three mutually exclusive g roups by parental report of: asthma, wheeze, and no asthma/no wheeze. A ran dom sample of 80 children in each group was tested (n=240). Among asthmatic s, 68% (95% confidence interval (CI), 57-79) had a BHR (measured as PD20 fo rced expiratory volume in 1 s (FEV1) less than or equal to 8.16 mu mol usin g methacholine) compared to 31% (CI 20-42%) and 30% (CI 19-40%) in the whee ze and no asthma/no wheeze groups. The dose-response slope (DRS) confirmed the PD20 data and distinguished equally between groups. EIB (greater than o r equal to 10% fall in FEV1) was more frequent (40%, CI 29-52%) among asthm atics than among children with wheeze (12%, CI 4-19%) and no asthma/no whee ze (7%, CI 1-13%). The prevalence of at least one positive SPT was twice as high in the asthma group (58%, CI 47-69%) than in the wheeze (27%, CI 16-3 7%) and the no asthma/no wheeze (25%, CI 15-35%) groups. These results indi cate that children with asthma differ from children with wheeze and childre n with no asthma/no wheeze regarding lung function, BHR, EIB, and SPT react ivity. Children with wheeze are more similar to children with no asthma/no wheeze with respect to these parameters.