[Risk factors for atopic dermatitis and familial prevalence in Spain (ELIHO study)]

Atopic dermatitis (AD) is a cutaneous disease of unknown etiology. It shows a clear genetic predisposition with probable environmental modulation. This study evaluated risk factors associated with diagnosis and flares of AD in Spanish children.

We performed an observational, multicenter, retrospective case-control study that included 4243 children aged less than 14 years old with AD and 978 controls matched for age and sex. Family history of disease and environmental variables were collected in both groups and clinical history of AD was recorded in the case group.

Significant risk factors for AD were: a family history of the disease and concomitant cutaneous infections. The prevalence of AD in first degree relatives was 39 % and that in second degree relatives was 19 % (higher in maternal than paternal lines). The mean age of children with AD was 4.2 (SD 3.4) years and the mean age at diagnosis was 1.5 (SD 2.2) years, with a mean of 2.9 (SD 2.6) flares during the previous year. Cold weather (Cantabrian and Continental Iberian Peninsula areas) was related to a greater number of flares. Children with AD had a greater number of concomitant cutaneous diseases and infections than children in the control group.

AD is mainly a genetic disease, with climatic factors involved in severity modulation, and with important immunological alterations. In contrast, this study found no domestic environmental factors that were associated with disease onset.