Almost two years ago, the first JAK inhibitor was approved for the treatment of alopecia areata, and a second followed in 2023. But what can JAK inhibitors actually do in the treatment of inflammatory hair diseases?
“Alopecia areata is on everyone's lips right now because we as dermatologists are once again experiencing a mini-revolution with a new class of products,” says Apr. Professor Dr. Johannes Gries, Senior Physician at the University Clinic for Dermatology and Head of the Immunodermatology Outpatient Clinic and Hair Clinic at Meduni Vienna, introduced his lecture at the ÖGDV Annual Meeting. Alopecia areata is one of the most common autoimmune diseases with a lifetime incidence of about 2%. Both sexes are equally affected. However, this disease manifests itself more often in children and adolescents than in adults. The pathogenesis is currently still unclear.
Inflammatory hair diseases have immunologic specificity because hair follicles in mammals are particularly conserved from an evolutionary perspective. “From an immunological perspective, the hair follicle is a unique organ,” Kris says. This is the result of a phenomenon called immune privilege, which means that certain organs are “hidden” from the immune system. In addition to anagen hair follicles, such immune privilege has been described for parts of the cornea, testis, placenta, liver, intestine, and brain. By this the hair follicles are protected from the immune system during the vulnerable phase of pigmentation and hair production; It effectively prevents inflammation.