JAK inhibitor halts the progression of acute exacerbation of alopecia areata

Summary: Abstract Body: JAK inhibitors have been shown to be beneficial for chronic alopecia areata. Their effects on the acute stage of alopecia areata remain uclear. This study aimed to evaluate the efficacy of baricitinib, a Janus kinase inhibitor (JAKI), in halting active hair shedding and promoting hair regrowth in patients with acute alopecia areata (AA) to determine whether early treatment could alter the disease progression. A retrospective review was performed on patients experiencing a new AA episode within three months, with over 30% of the scalp affected by active hair shedding confirmed by a positive hair pull test. All patients were treated with baricitinib (4 mg/day, titrated as needed) for at least three months between November 2022 and July 2024. Baricitinib reduced hair shedding within 2 to 15 weeks (mean 8 weeks), completely halting shedding at 12 weeks. Hair pull tests became negative in all patients by four months, and hair regrowth at an average of 11 weeks. By six months, no patients had a Severity of Alopecia Tool (SALT) score greater than 20. This study showed that JAKI exert beneficial effect on the acute stage of alopecia areata. JAKI, including baricitinib (Olumiant) and ritlecitinib (Litfulo), have demonstrated success in treating chronic AA with extensive hair loss. However, data on their effects in acute active AA remains limited, and whether early treatment with JAKIs can prevent progression to the chronic phase remains to be clarified. While this study suggests that early baricitinib intervention may modify the disease course by rapidly halting hair shedding and promoting regrowth, limitations such as the small sample size, and short follow-up duration warrant further investigation. Future studies should evaluate the broader efficacy of JAKIs in managing acute AA. Tyng-Shiuan Hsieh^{1, 2, 3}, Sung-Jan Lin^{2, 3, 4} 1. Cancer Branch, National Taiwan University Hospital, Taipei, Taiwan. 2. Department of Biomedical Engineering, National Taiwan University, College of Medicine and College of Engineering, National Taiwan University, Taipei, Taiwan. 3. Department of Dermatology, National Taiwan University Hospital, Taipei City, Taiwan. 4. Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan. Clinical Research: Interventional Research