An independent relation of atopic dermatitis to exercise-induced wheezing in asthmatic children.

BACKGROUND: Atopic dermatitis (AD) and exercise-induced asthma (EIA) are common in asthmatic children, and exercise is the most common trigger other than infection for acute onset asthma attack in children. We examined whether AD is related to exercise-induced wheezing (EIW), some proxy for EIA. METHODS: Japanese version of the International Study of Asthma and Allergies in Childhood questionnaires were used. For 12,405 asthmatic school children, AD was defined as itchy rash coming and going for at least 6 months at any time in the last 12 months with affecting places of flexural parts of body, and severity of AD was rated according to frequency of being kept awake at night with the itch as follows: never in the past 12 months, less than one night per week and one or more nights per week. RESULTS: Adjusted for frequency of asthma attack, odds ratios (OR) of children with current AD as compared to those without AD for having EIW were 1.32 (95% confidence interval = 1.15-1.52), 1.35 (1.14-1.68) and 1.10 (0.92-1.31) for primary school, junior high school and high school children, respectively. EIW was more likely observed in accordance with increasing severity of AD in the primary school children with ORs of 1.12, 1.59 and 1.54 (p for trend < 0.01), and in the junior high school ones with ORs of 1.18, 1.31, 2.03 (<0.01), respectively. CONCLUSIONS: AD may be possibly related to EIW. Further studies investigating effect of AD treatment on EIW may be required.