Episodes of respiratory morbidity in children with cough and wheeze

Abstract

An important feature of "asthma" in children is the occurrence of repeated episodes of airflow obstruction lasting days or weeks. In this 1-yr longitudinal study, we investigated the nature of these episodes and their relationship to other indices of asthma. A random sample of children aged 7 and 8 yr reporting either cough or wheeze was invited to attend for skin testing. Ninety-six atopic children, half with cough and half with wheeze, and 96 nonatopic children, again half with cough and half with wheeze, were selected to join a longitudinal study. All children recorded twice daily peak expiratory flow (PEF) measurements and a daily 10-point symptom score. One hundred eighty-three children (95.3%) successfully completed the study. Episodes of respiratory morbidity, defined as falls in PEF to less than 1.5 standard deviations (SD) below subject mean lasting for more than 2 days, were identified and the 642 resulting episodes examined. Episodes were more common in autumn and winter (p = 0.003 to 0.017). The mean number of episodes per child was 3.5 (range 0 to 8): 94 (51.4%) children experienced more than three episodes, 54 (30.0%) experiencing five or more. The average duration of episodes was 4.1 days (range 2 to 27 days), with 44 (24%) subjects demonstrating episodes of average duration of 5 days or more and 18 (10%) of greater than 7 days. Episodes were more severe in children with wheeze (p = 0.013) and slightly more frequent in those with cough alone (p < 0.05). Atopy had no effect on episode frequency, duration, or magnitude.