PROFESSOR ANDREW MESSENGER MD FRCP
A study on the epidemiology of alopecia areata in the UK has recently been published in the British Journal of Dermatology . It is currently online only but due to appear in print in the near future in open access form.
The investigators used a large primary care database containing over 4.1 million records from English general practices giving information on diagnoses, demographics, prescribing and referrals. 6675 new cases of alopecia areata were recorded over a 10-year period 2009-2018, giving an incidence rate of 0.26 cases per 1000 patient years (approx. 1 new case per 4000 people per year). The point prevalence at the end 2018, the proportion of the study population with a diagnosis of alopecia areata at any prior timepoint, was 0.58% which, extrapolated to the population at large, indicates that around 400,000 people in the UK either have active alopecia areata or have had it in the past.
The incidence rate was higher in people living in urban areas, in those living in more deprived areas and in non-white groups, particularly in people of Asian ethnicity where the incidence rate was over threefold greater than in the white population. Overall, 1 in 4 people with a new diagnosis of alopecia areata were referred to a specialist. Those living in more deprived areas were less likely to be referred.
This study provides valuable information on the burden of alopecia areata on the population and on health services. The implications of the results, in terms of their impact on how new and more effective, but more expensive treatments are funded and targeted, are discussed in an accompanying editorial by Rodney Sinclair . The differences in incidence rates between different groups, particularly between different ethnic groups, was a striking feature of the study. At present we can only speculate about the reasons for these disparities but they may give clues to causation and provide targets for future research.