Janus kinase inhibitors for alopecia areata.

Janus kinase (JAK) inhibitors have ushered in a new era in alopecia areata (AA). Historically, moderate-to-severe AA was refractory to treatment. JAK inhibitors have changed that; now, treatment of moderate-to-severe AA is possible. Here, we briefly review the history of and rationale for JAK inhibitor treatment of AA, phase 3 clinical trial data, and considerations regarding differences among JAK inhibitors, safety, and patient selection.