Atopic dermatitis possibly related to exercise-induced wheezing among asthmatics
There appears to be a positive relationship between atopic dermatitis (AD) and exercise-induced wheezing (EIW) among children with asthma, a study from Japan suggests.
The present analysis included 12,405 asthmatic school children who completed a Japanese version of the International Study of Asthma and Allergies in Childhood questionnaires. A total of 3,441 had current AD (defined as itchy rash appearing and disappearing for at least 6 months at any time during the past year), among whom 61.1 percent experienced EIW. AD severity was rated according to frequency of being kept awake at night: never in the past 12 months, <1 night per week and ≥1 nights per week.
Multiple logistic regression models adjusted for frequency of asthma attack showed that children with AD were more likely to have EIW than their non-AD peers (primary school children: odds ratio [OR], 1.32; 95 percent CI, 1.15–1.52; junior high school children: OR, 1.35; 1.14–1.68; high school children: OR, 1.10; 0.92–1.31).
Moreover, the odds of having EIW increased with severity of AD in primary school (ORs, 1.12, 1.59 and 1.54; p<0.01 for trend) and junior high school children (ORs, 1.18, 1.31 and 2.03; p<0.01 for trend).
The mechanism underlying the relationship between AD and EIW may involve the cysteinyl leukotrienes (LTC4, LTD4 and LTE4), which have been shown to alter airway tone directly in relation to pathogenesis of EIA. Another is nitric oxide, which has a critical effect on bronchial calibre and vasomotor tone in EIA, while AD is positively associated with fractional exhaled nitric oxide among children with suspected asthma. [Clin Exp Dermatol 2004;29:277-281; Ann Allergy Asthma Immunol 2013;111:358-363]
Researchers, however, warned against making causal inferences from the current findings, as the study was based on cross-sectional data. Additional studies exploring the effect of AD treatment on occurrence of EIW are of interest and should contribute to advancement of care for asthmatic children.