Importance: Pediatric alopecia areata (AA) prevalence and incidence data are key to understanding the natural history of this medical disease.
Objective: To determine the prevalence and incidence of AA in a pediatric population across time, age, sex, race and ethnicity, and geographic areas within the US.
Design, setting, and participants: In this multicenter cohort study conducted among 5 children's hospitals, data (January 2009 to November 2020) were collected from a standardized electronic health record (PEDSnet database, version 4.0) to evaluate the incidence and prevalence of pediatric AA. The study cohort included patients younger than 18 years with at least 2 physician visits during which a diagnosis code for AA was recorded, or 1 dermatologist specialty visit for which AA was recorded.
Main outcomes and measures: The prevalence denominator population comprised 5 409 919 patients. The incidence denominator population was 2 896 241. We identified 5801 children for inclusion in the AA cohort, and 2398 (41.3%) had 12 months or more of follow-up and were included in the incidence analysis.
Results: Of 5801 patients in the AA cohort, the mean (SD) age was 9.0 (4.5) years, 3259 (56.2%) were female, 359 (6.2) were Asian, 1094 (18.9%) were Black, 1348 (23.2%) were Hispanic, and 2362 (40.7%) were White. The overall prevalence of pediatric AA was 0.11%, and the participants in the AA cohort were more often older, female, and members of a racial and ethnic minority group than the full PEDSnet population. The 11-year overall incidence rate of pediatric AA between 2009 and 2020 was 13.6 cases per 100 000 person-years (95% CI, 13.1-14.2). The incidence rate by age was normally distributed and peaked at age 6 years. Rates were 22.8% higher in female patients than male patients (15.1 cases per 100 000 person-years for females vs 12.3 cases per 100 000 person-years for males). Additionally, incidence rates were highest among Hispanic children (31.5 cases per 100 000 person-years).
Conclusions and relevance: This cohort study examined the prevalence and incidence rates of pediatric AA in the US across time, age, sex, race and ethnicity, and region from 2009 to 2020, finding a prevalence of 0.11% (doubling during the last decade) and incidence rate of 13.6 cases per 100 000 person-years. Additionally, the results identified Asian and Hispanic children as high-risk demographic subgroups who were shown to be 2 and 3 times more likely, respectively, to receive a diagnosis of AA.