Different clinical phenotypes of nail abnormalities in patients with severe atopic dermatitis: a single-centre cross-sectional study.

Introduction: Nail involvement in atopic dermatitis (AD) remains an underrecognized and understudied manifestation, despite its potential to significantly contribute to disease burden. Aim: This study objective was to characterize the prevalence, types, and patterns of nail abnormalities in patients with severe AD and to explore clinical factors associated with their occurrence. Material and methods: This single-centre, cross-sectional study included adult patients with severe AD (EASI > 21) diagnosed according to the Hanifin and Rajka criteria. Demographic, clinical, and laboratory data were collected, and hand nails were examined for abnormalities. Statistical analyses included Fisher's exact test, χ Results: Forty-seven participants (28 males, median age 37.0 years) were included. Glossy nails were the most frequent abnormality (94%), followed by paronychia (40%) and Beau's lines (36%). Higher EASI scores were significantly associated with Beau's lines, onychomadesis, eczema of nail folds, petechiae, and paronychia ( Conclusions: Nail abnormalities are highly prevalent in severe AD and closely related to disease severity. Distinct phenotypic patterns of nail involvement may reflect varying degrees of structural damage and could have implications for clinical management. Systematic nail assessment should be incorporated into routine AD evaluation.