Dual improvement of alopecia areata and immune thrombocytopenia with baricitinib: a case report.

The oral Janus kinase (JAK) inhibitor baricitinib is approved by the U.S. Food and Drug Administration for the treatment of alopecia areata (AA). We report a case of dual improvement of AA and immune thrombocytopenia (ITP) with oral baricitinib monotherapy, which may suggest linked autoimmune pathophysiology. In phase III clinical trials of baricitinib for AA, reports of rare adverse haematological events include neutropenia and anaemia. While a history of haematological comorbidities may raise concern for many clinicians when considering treatment with a JAK inhibitor, this clinical vignette suggests that baricitinib may be considered and safely administered in those with concomitant AA and ITP. A 56-year-old man with a history of AA, ITP and vitiligo presented to the clinic for relapse of his steroid-resistant hair loss which had previously been treated with tofacitinib. In consultation with the patient's haematologist, baricitinib 2 mg daily was started with close platelet monitoring then doubled to 4 mg after platelets showed improvement at the 6-month follow-up. Fourteen months after initiating baricitinib, improvement in white and dark hair regrowth was observed, and platelets remained normal. Thus, baricitinib may be considered for the dual treatment of AA and ITP with regular platelet monitoring and co-management with haematology colleagues.