The epidemiology of alopecia areata: a population-based cohort study in UK primary care.

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. WHAT IS ALREADY KNOWN ABOUT THIS TOPIC?: Alopecia areata (AA) is a common cause of nonscarring hair loss associated with psychological morbidity. Large-scale population-based information on the disease burden and clinical management of AA is lacking. What does this study add? In the largest population-based study of AA to date, comprising 4·16 million people, we estimate that new-onset AA peaks at age 25-29 years. People of Asian ethnicity, and from socially deprived and urban areas, are more likely to present with AA. After diagnosis, one in four people with AA are referred for specialist dermatology review. Specialist referral rates are lower in people from more socially deprived areas.