Eczema severity in preadolescent children and its relation to sex, filaggrin mutations, asthma, rhinitis, aggravating factors and topical treatment: a report from the BAMSE birth cohort

Background Filaggrin (FLG) mutations are major genetic determinants for eczema, but their role in eczema severity needs further investigation. Children with eczema are at higher risk of having asthma and rhinitis but it is not known if this risk is associated with the severity of eczema. Objectives To investigate eczema severity in relation to sex, FLG mutations, asthma, rhinitis and topical treatment among preadolescent children in a population-based cohort. Methods Parental questionnaires were used to obtain data on symptoms of eczema, asthma, and rhinitis among 3301 preadolescent children. Eczema severity was evaluated based on sleep disturbance, extent of disease and total time with eczema the previous year. Genotyping was performed in 1854 individuals for three common FLG mutations (R501X, R2447X and 2282del4). Results Eczema was more prevalent among girls (14.5%) than boys (9.4%). FLG mutations were detected in 13.1% of children with mild eczema and 12.5% with moderate-to-severe eczema. Of children with moderate-to-severe eczema, 45.1% had rhinitis and 22.0% had asthma compared with 32.7% and 13.8% of children with mild eczema, respectively. Children with moderate-to-severe eczema used moisturizers and topical glucocorticoids more frequently than children with mild eczema. Boys used moisturizers less frequently than girls. Conclusions More preadolescent girls than boys had eczema. FLG mutations did not influence eczema severity in our population-based cohort. Prevalence of rhinitis and asthma was associated with eczema severity, with the highest prevalence among boys with moderate-to-severe eczema.