Atopic dermatitis phenotypes in preschool and school-age children: a latent class analysis.

BACKGROUND: Atopic dermatitis (AD) represents the most common chronic inflammatory skin disease in childhood. Few data are available about the different AD phenotypes and their nationwide distribution. METHODS: We performed a cross-sectional multicentre study involving some of the main Italian paediatric allergy centres in 9 Italian cities. A structured questionnaire was administered to 371 children with AD. Patients were divided in two groups: preschool children (aged <5 years) and schoolchildren (aged 6-14 years). A latent class analysis (LCA) was used to detect AD phenotypes and to investigate their association with risk factors and other atopic diseases. RESULTS: LCA identified five AD phenotypes in preschoolers group (8% "moderate-severe AD, high comorbidity", 35% "moderate-severe AD, low comorbidity", 20% "mild AD, low comorbidity", 32% "mild AD, respiratory comorbidity", 5% "mild AD, food-induced comorbidity") and four AD phenotypes in schoolchildren (24% "moderate-severe AD, high comorbidity", 10% "moderate-severe AD, low comorbidity", 16% "mild AD, low comorbidity", 49% "mild AD, respiratory comorbidity"). Parental history of asthma and eczema, early day-care attendance and mould exposure were associated significantly to the "moderate-severe AD, high comorbidity" phenotype in preschool children (p<0.05). The "moderate-severe AD" phenotypes showed also to have the higher burden in terms of medication use and daily activities limitation. CONCLUSIONS: The detection of different AD phenotypes suggests the importance of a stratified approach to the management of this complex disease and the need of further studies to predict AD course and to develop more efficient therapeutic strategies.