Epidemiology of alopecia areata and its association with atopic dermatitis: A comparative analysis of data from the Moscow Center of Dermatovenereology and Cosmetology and the Federal Registry; Эпидемиология гнездной алопеции и ее ассоциации с атопическим дерматитом: сравнительный анализ данных Московского центра дерматовенерологии и косметологии и федерального регистра

Introduction. One of the frequent comorbid conditions in alopecia areata is atopic dermatitis. Existing epidemiological data on alopecia areata and its association with atopic dermatitis remain contradictory and insufficiently studied, which underscores the relevance of this research. Aim. To study the epidemiological characteristics of alopecia areata in Moscow and its association with atopic dermatitis based on population and registry data. Materials and methods. A multicenter retrospective cohort study was conducted by analyzing medical records of patients diagnosed with alopecia areata and atopic dermatitis monitored at the Moscow Center for Dermatovenereology and Cosmetology from 2020 to 2024. Federal statistics (Form No. 12), outpatient records (No. 025/u-04), and a specialized alopecia areata registry were used. Rates per 100 000 population were calculated. Results. Significant differences in alopecia areata epidemiology were found (p < 0.001): prevalence in children (36.8/100 000) was 2.7 times higher than in adults (13.7/100 000), incidence – 22.2 vs. 7.9/100 000/year. Overall morbidity increased by +83.3%, prevalence by +62.6% (p < 0.001). The association between alopecia areata and atopic dermatitis was significant (p < 0.001): overall frequency 2.66% (95% CI: 2.37–2.95), higher in children (4.09%; OR = 8.3, 95% CI: 7.1–9.7) than adults (1.85%; OR = 14.1, 95% CI: 11.9–16.7). The highest increase occurred in 2021. In the adult alopecia areata registry, atopic dermatitis was present in 15.9% (64/403). Conclusions. The significant age-dependent association between alopecia areata and atopic dermatitis confirms atopic dermatitis as an established risk factor. Registry data provide more accurate information on comorbidities. The results justify screening for atopy in alopecia areata patients and the need for a multidisciplinary management approach. © 2025 Elsevier B.V., All rights reserved.