Global, Regional, and National Burden of Alopecia Areata in Children and Adolescents Aged 0-19 years from 1990 to 2021 and Projection to 2040

Background: Global epidemiological patterns of alopecia areata in pediatric populations remain inadequately characterized. We evaluated the disease burden and trends among children and adolescents aged 0– 19 years across 204 countries and territories from 1990 to 2021 and projected the disease development from 2022 to 2040. Methods: Using Global Burden of Disease (GBD) 2021 data, we analyzed incidence, prevalence, and disability-adjusted life years (DALYs), stratified by sex, age, and Sociodemographic Index (SDI). Temporal trends were quantified via estimated annual percentage changes (EAPC) in age-standardized rates. The Bayesian age cohort model was used to predict prevalent cases trend from 2022 to 2040. Results: In 2021, global prevalent cases increased by 15.79% (1990– 2021), yet age-standardized incidence (ASIR), prevalence (ASPR), and DALY rates (ASDR) declined significantly (EAPC range: − 0.092 to − 0.099). Females consistently bore 75% higher burden than males. Disease metrics escalated with age, peaking in the 15– 19 age subgroup. Low-SDI group exhibited rising ASIR/ASPR/ASDR (EAPC up to 0.050), contrasting declines in higher-SDI areas. High-income North America recorded the highest ASPR (145.84/100,000) but the most rapidly decline (EAPC=− 0.251), while Central Sub-Saharan Africa showed the steepest increases. India reported the highest national prevalent cases (420,913) in 2021. The disease burden of alopecia areata among children and adolescents aged 0– 19 years worldwide and in India will tend to be stable from 2022 to 2040, while the disease burden in China will rise, and in the United States of America, it will continue to decline. Conclusion: Despite a decrease in the relative burden, the absolute number of alopecia areata cases rose globally. Critical disparities persist among females, adolescents (15– 19 years), and low-SDI populations—particularly in Central Sub-Saharan Africa. Targeted interventions for these vulnerable groups are urgently needed. Keywords: alopecia areata, global burden of disease, incidence, prevalence, disability-adjusted life years, children and adolescents