The Development of Oral Hairy Leukoplakia During JAK Inhibitor Baricitinib Therapy

The document presents a case of a 50-year-old man with alopecia universalis (AU) who developed oral hairy leukoplakia (OHL) while on baricitinib therapy. Baricitinib is a JAK1/JAK2 inhibitor used for treating refractory rheumatoid arthritis and severe alopecia areata (AA). The patient, who had a 25-year history of AU, started on baricitinib therapy in July 2022. By March 2023, he showed patchy hair regrowth on his scalp, arms, axilla, and eyebrows. However, he was also diagnosed with OHL during a routine dental visit in the same month. The document suggests that all JAK inhibitors, including baricitinib, pose the risk of immune-related adverse events due to their downregulation of cytokines and growth factors involved in the adaptive immune response. The document concludes that clinicians should be aware of this potential adverse event during JAK inhibitor therapy for timely and appropriate patient management.