Abstract
Background/Objectives: Alopecia areata (AA) is a common autoimmune disorder with substantial psychosocial impact, but contemporary assessments of its epidemiology and future burden remain limited. We aimed to comprehensively characterize the epidemiology of AA using the most recent Global Burden of Disease (GBD) 2023 data. Methods: GBD 2023 data were used to estimate regional AA incidence. Bayesian age-period-cohort modeling projected incidence through 2040, and decomposition analysis quantified the contributions of population growth, population aging, and epidemiologic change to increases in incident cases from 1990 to 2023. Age-specific incidence patterns were compared across six GBD regions, and associations between the Socio-demographic Index (SDI) and age-standardized incidence rates (ASIRs) were evaluated. Results: Marked regional variation in AA burden was observed in 2023, with South Asia accounting for the largest number of incident cases, while Sub-Saharan Africa experienced the greatest historical increase. Projections suggested South Asia, Sub-Saharan Africa, and High-income North America will contribute the largest increases in global AA incidence through 2040. Population growth was the predominant driver of increasing incident cases. Age-specific incidence consistently peaked at 30–34 years and remained highly conserved across regions. Higher SDI was associated with higher regional ASIRs. Conclusions: Future increases in AA burden are expected to be driven predominantly by population growth despite relatively stable ASIRs. Although regional disease burden varied substantially, age-specific incidence patterns remained highly conserved, whereas higher socioeconomic development was associated with higher incidence rates. These findings provide an updated global perspective on AA and may inform future epidemiologic research, healthcare planning, and resource allocation.