▼Ritlecitinib for severe alopecia areata

### What you need to know Alopecia areata is an autoimmune disease against hair follicles, characterised by hair loss of the scalp, face and/or body, with nail involvement (eg, pitting or ridging) in 10–15% of cases.1–3 Human skin biopsy specimens from people with alopecia areata show the overexpression of Janus kinase 3 (JAK3) and, to a lesser extent, JAK1 and JAK2, which are involved in promoting inflammation via T cells and cytokines.4 The prevalence of alopecia areata has been estimated as 0.6% in Europe.5 6 In the UK, the annual incidence was found to be highest in people aged 25–29 years (5.1 per 10 000 males and 4.3 per 10 000 females) and then decreased with age.7 It can affect all ages, races and genders.5 People of Asian ethnicity, and from socially deprived and urban areas are more likely to present with alopecia areata.7 A family history of the condition, or chromosomal disorders such as Down syndrome, may increase the risk of alopecia areata,3 and it may be associated with other autoimmune diseases such as thyroiditis, type 1 diabetes and rheumatoid arthritis.8 It may be a self-limiting condition, especially in the early stages or where there is <25% hair loss. …