JAK1 and alopecia areata: Upadacitinib inhibits JAK1, and its mechanism has a narrower target than other JAK inhibitors that are FDA-approved for alopecia areata, such as ritlecitinib, a JAK3/TEC-kinase inhibitor, and baricitinib, a JAK1/2 inhibitor [2]. This case raises questions about why alopecia areata would present in a patient undergoing a drug treatment designed to modulate the JAK pathway.