Abstract and Introduction
Abstract
Background: There is a lack of population-based information on the disease burden and management of alopecia areata (AA).
Objectives: To describe the epidemiology of AA, focusing on incidence, demographics and patterns of healthcare utilization.
Methods: Population-based cohort study of 4·16 million adults and children, using UK electronic primary care records from the Oxford-Royal College of General Practitioners (RCGP) Research and Surveillance Centre (RSC) network database, 2009–2018. The incidence and point prevalence of AA were estimated. Variation in AA incidence by age, sex, deprivation, geographical distribution and ethnicity was examined. Patterns of healthcare utilization were evaluated in people with incident AA.
Results: The AA incidence rate was 0·26 per 1000 person-years. AA point prevalence in 2018 was 0·58% in adults. AA onset peaked at age 25–29 years for both sexes, although the peak was broader in females. People of nonwhite ethnicity were more likely to present with AA, especially those of Asian ethnicity [incidence rate ratio (IRR) 3·32 (95% confidence interval 3·11–3·55)]. Higher AA incidence was associated with social deprivation [IRR most vs. least deprived quintile 1·47 (1·37–1·59)] and urban living [IRR 1·23 (1·14–1·32)]. People of higher social deprivation were less likely to be referred for specialist dermatology review.
Conclusions: By providing the first large-scale estimates of the incidence and point prevalence of AA, our study helps to understand the burden of AA on the population. Understanding the variation in AA onset between different population groups may give insight into the pathogenesis of AA and its management.
Introduction
Alopecia areata (AA) is a common, immune-mediated nonscarring alopecia and can be associated with severe psychological consequences.[1,2] Despite being a relatively common condition, robust and recent epidemiology data for AA are lacking. The only previous population-based estimate of AA incidence rate (IR) of 0·21 per 1000 person-years is from the US Rochester Epidemiology Project (REP), but this was based on only 530 people with AA.[3] The mean age of AA onset has been suggested to be between 25 and 36 years,[3–6] with no clear sex differences,[3–9] although these estimates have largely been generated from clinic-based studies, meaning they are likely to be missing a large proportion of people with milder forms of AA who do not receive specialist management.[4–9]
Information on current treatment patterns and pathways to specialist care for people with AA is similarly limited. Although topical steroids, intralesional steroids and contact immunotherapy are recommended in current UK guidelines,[10] the optimal treatment pathway is not clear. A 2008 Cochrane Review examined 17 randomized control trials encompassing 540 patients and found no evidence of a significant benefit compared with placebo for any treatment examined.[11] For disease of limited extent topical minoxidil and dithranol may offer some benefit, while systemic immunosuppressants are sometimes used in severe alopecia areata.[10] No previous studies have robustly evaluated treatment patterns in AA, or healthcare utilization after clinical diagnosis.
In the UK, general practitioners (GPs) are usually the first point of contact for new cases, with secondary care referrals reserved for those not responding to first-line treatments, those presenting with extensive or rapidly advancing disease, or where the diagnosis is uncertain.[12] In this population-based setting we aimed to describe the contemporary epidemiology of AA, and common patterns of healthcare utilization and treatment.
The British Journal of Dermatology. 2022;186(2):257-265. © 2022 Blackwell Publishing
