Phenotypes and clinical outcomes in children with moderate‐to‐severe atopic dermatitis across diverse ancestries: a Spanish multicenter observational study and cluster analysis (AD‐SKINS Project)

BACKGROUND AND OBJECTIVES: Atopic dermatitis (AD) has a highly variable clinical phenotype and ancestry can contribute to this heterogeneity. This study aims to identify clinical phenotypes of AD in children from diverse ancestry groups, evaluate clinical outcomes and response to treatment, and define phenotypic clusters with potential relevance. PATIENTS AND METHODS: Multicenter, descriptive, observational study of patients with moderate-to-severe AD treated in eight Spanish hospitals. Patient ancestry was based on self-reported parental origin and country of birth. Phenotypic clusters were identified through analysis of demographic, clinical, and morphological variables. Systemic treatment response was assessed using validated AD scales. RESULTS: 157 children were categorized into five ancestry groups: American Indian, Asian, Black, Mixed, and White. Three phenotypic clusters were identified. Cluster 1 had varied ancestries and the highest rate of Th2 comorbidities. Cluster 2 patients were mostly Asian with a predominantly non-classic morphologies, and a higher rate of hospital admissions. Cluster 3 were mostly white with fewer Th2 comorbidities. Systemic treatments yielded differential responses across clusters. Cluster 1, slower response; Cluster 2, fastest improvement; Cluster 3, milder disease and consistent improvement. CONCLUSIONS: We propose a clinically based clustering framework to refine pediatric AD phenotypes and support individualized care across diverse ancestries.