Phenotypes of atopic dermatitis in Polish children-Latent class analysis of cross-sectional questionnaire-based study.

BACKGROUND

Atopic dermatitis (AD) is a common chronic inflammatory skin disease with a heterogeneous clinical course. Distinct phenotypes show differences in age at onset, severity, and allergic profile; however, evidence from Central and Eastern Europe remains limited.

METHODS

An anonymous online questionnaire distributed via social media targeted parents of children <18 years of age with physician-diagnosed AD. The data included demographics, environmental exposures, AD history, proxy Patient-Oriented Eczema Measure (POEM) scores, comorbidities, and self-reported sensitizations. Children were stratified by age (<6 vs. ≥6 years). Latent class analysis (LCA) was used to identify phenotypes in age groups using age of onset, current severity, recent exacerbations, viral skin infections, and sensitization type.

RESULTS

A total of 435 children were included in this analysis (mean age, 3.92 years; 59.8% male). AD onset before 6 months occurred in 67.1% of patients. In children <6 years (n = 359), three phenotypes were identified: "early-onset, moderate-severe with co-sensitization" (n = 100, 27.9%), with highest frequency of food allergy; "early-onset, mild with food sensitization" (n = 195, 54.3%), and "later-onset, mild with aeroallergen sensitization" (n = 64, 17.8%). In children ≥6 years (n = 76), two phenotypes emerged: "early-onset with co-sensitization" (n = 53, 69.7%), which displayed higher frequency of atopic comorbidities, and "later-onset with aeroallergen sensitization" (n = 23, 30.3%). The classes showed clear separation based on selected features.

CONCLUSIONS

Distinct, clinically relevant AD phenotypes were identified in children, which were in line with phenotypes reported in previous longitudinal studies, although based on cross-sectional data. These findings underscore AD heterogeneity and support the utility of pragmatic, region-specific surveys for phenotype identification outside longitudinal cohorts.