Alopecia areata (AA) is a common autoimmune alopecia with heterogeneous severity and distribution. Previous studies found conflicting results about AA epidemiology.
To determine the prevalence, incidence, and predictors of AA, alopecia totalis, alopecia ophiasis, and alopecia universalis.
A systematic review of all published cohort and cross-sectional studies that analyzed AA and its subtypes. MEDLINE, Embase, LILACS, Scopus, Cochrane Library, and GREAT were searched. At least 2 reviewers performed study title/abstract review and data extraction. Random-effects meta-analysis was used because of significant heterogeneity (I2 = 99.97%).
Ninety-four studies met the inclusion criteria. The pooled prevalence (95% confidence interval, N) of AA overall was 2.11% (1.82-2.42, N = 302,157,365), with differences of population-based (0.75% [0.49-1.06%], N = 301,173,403) and clinic-based (3.47% [3.01-3.96], N = 983,962) studies. The prevalences of alopecia totalis, ophiasis, and universalis were 0.08% (0.04-0.13, N = 1,088,149), 0.02% (0.00-0.06, N = 1,075,203), and 0.03% (0.01-0.06, N = 1,085,444), respectively. AA prevalence (95% confidence interval) increased over time (<2000: 1.02% [0.85-1.22]; 2000-2009: 1.76% [1.51-2.03]; >2009: 3.22% [2.59-3.92]; P < .0001) and differed by region. AA prevalence was significantly lower in adults (1.47% [1.18-1.80]) than children (1.92% [1.31-2.65]; P < .0001).
AA affects 2% of the global population. AA prevalence is lower in adults than children, is increasing over time, and significantly differs by region.Le texte complet de cet article est disponible en PDF.
Key words : alopecia areata, alopecia ophiasis, alopecia totalis, alopecia universalis, epidemiology, meta-analysis, prevalence, systematic review
Abbreviations used : AA, AO, AT, AU, CI
| Funding sources: Supported by the Agency for Healthcare Research and Quality (grant no. K12 HS023011) and the Dermatology Foundation.
| Conflicts of interest: None disclosed.
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