Rapid and Sustained Improvement of Lichen Planus Pemphigoides With the JAK1 Inhibitor Upadacitinib

ABSTRACT Lichen planus pemphigoides (LPP) is a rare autoimmune blistering disorder characteris ed by lichenoid plaques and blister formation. Current treatments are often ineffective, and there is a lack of standardised guidelines. The disease's pathogenesis involves both T‐cell‐mediated lichenoid dermatitis and autoantibody formation, presenting treatment challenges, especially in refractory cases. While previous therapies have focused on immunosuppressive agents, many patients fail to achieve sustained remission. Here, we report a case of LPP successfully treated with the Janus kinase 1 (JAK1) inhibitor upadacitinib. The patient, a 56‐year‐old female with pruritic lichenoid lesions and blisters, experienced rapid symptom resolution following treatment. Notably, pruritus subsided within days, and both skin lesions and anti‐BP180 antibody levels improved substantially within 1 month. Remarkably, the patient remained nearly symptom‐free for 6 months posttreatment. This case demonstrates that JAK1 inhibition can offer rapid and sustained clinical improvement in LPP, with the potential for disease modification. These findings suggest that early, targeted intervention with JAK inhibitors may provide a new therapeutic avenue for autoimmune skin diseases, particularly those resistant to traditional treatments.