Real-world Effectiveness and Safety of Janus Kinase Inhibitors in Alopecia Areata: A Retrospective Cohort Study of 72 Patients.

Alopecia areata (AA) is an autoimmune hair loss disorder characterized by sudden hair shedding due to immune dysregulation involving the Janus Kinase - Signal Transducer and Activator of Transcription (JAK-STAT) pathway. JAK inhibitors (JAKi) have demonstrated efficacy in clinical trials, but data from real-world settings remain scarce. This retrospective, single-centre cohort study evaluated the real-world effectiveness and safety of JAKi (abrocitinib, baricitinib, ritlecitinib, upadacitinib, and tofacitinib) in 72 patients treated between December 2017 and February 2024. Patients had a mean age of 34 years and a mean disease duration of 8 years. At time points 3, 6, 9, 12, and 18 months substantial regrowth was observed in 18 (25%), 28 (38.9%), 25 (34.7%), 22 (30.6%), and 19 (26.4%) patients respectively. Over a median follow-up of 16 months, 61% achieved substantial regrowth at a median time of 7 months. At 3, 6, 9, and 12 months, the cumulative regrowth rates were 11.1%, 40.2%, 55.6%, and 59.7%, respectively. Among non-responders who switched medications, 75% achieved substantial regrowth. Two serious adverse events occurred (sickle cell crisis and renal failure with pre-existing dysfunction). The findings indicate that JAKi are effective and safe for AA treatment in real-world settings. Further prospective studies are necessary to optimize treatment guidelines.