Summary 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.