Abstract
BACKGROUND: Dermatitis is a major global public health challenge. This study evaluates its burden from 1990 to 2021 and projects future burden over the next 20 years. METHODS: Data from the Global Burden of Disease Study 2021 (GBD 2021) included prevalence, incidence, disability-adjusted life years (DALYs), and age-standardized rates (ASRs), stratified by year, region, age, and Sociodemographic Index (SDI). Analyses used estimated annual percentage change (EAPC), inequality indices, decomposition, and Bayesian age-period-cohort (BAPC) modeling for forecasting. RESULTS: In 2021, global dermatitis cases reached 241 million (95% UI: 223.3-262.5 million), a 38.8% increase since 1990, but the age-standardized prevalence rate (ASPR) declined to 3,075.1 per 100,000 (EAPC = -0.14). Incident cases were 405 million (95% UI: 356-467 million), with the age-standardized incidence rates (ASIR) slightly increased to 4,945 per 100,000 (EAPC = 0.04). DALYs totaled 8.18 million (95% UI: 4.85-13.0 million), with the age-standardized DALY rate (ASDR) declining to 106.2 per 100,000 (EAPC = -0.18). ASPR and ASDR were highest in high-SDI regions and lowest in low-SDI regions; ASIR negatively correlated with SDI. Incidence peaked at ages 5-9 years. The burden was higher in males. A sharp DALYs rise occurred in those ≥65 years, especially in low/low-middle SDI regions. Projections indicate ASIR will slightly increase to 4,966 per 100,000 by 2040, while ASDR declines to 103 per 100,000. CONCLUSION: Despite rising absolute cases globally (driven by population growth), declining ASRs suggest diagnostic/therapeutic improvements. Marked disparities persist across SDI levels, age groups, and sexes. Strengthened prevention and resource allocation in low- and middle-income countries are needed to reduce health disparities.