Alopecia Areata

Abstract

Alopecia areata is a common, inflammatory, and non-scarring type of hair loss. It is pathogenetically characterized by a collapse of the immune privilege of the hair follicle to which altered genes implicated in the regulation of the innate and adaptive immune system as well as oxidative stress predispose. Following environmental triggers, an autoimmune response by autoreactive CD8⁺ T cells is mounted against the anagen hair follicle. Therapy of alopecia areata must be individualized and depends on the acuity, subtype, extent of disease, age of onset, and disease burden. Current treatment modalities include topical therapies (especially high-potency corticosteroids, intralesional corticosteroids, bimatoprost, contact immunotherapy, and minoxidil) and systemic interventions (especially corticosteroids and methotrexate). Baricitinib, a Janus kinase inhibitor, was recently officially approved in the Eurpean Union as a new treatment option for severe alopecia areata which also highlights a new era of novel systemic interventions targeting molecular pathogenetic pathways in alopecia areata.