Successful Treatment of Ustekinumab-Associated Lichenoid Drug Eruption with Upadacitinib: A Case Report.

Ustekinumab is an antibody targeting the common p40 subunit shared by interleukin (IL)-12 and IL-23, demonstrating favorable efficacy in the treatment of psoriasis. Herein, we report the case of a 69-year-old male with psoriasis, managed with ustekinumab, who presented with a new cutaneous eruption. Biopsy findings were consistent with lichenoid drug eruption (LDE). The patient's condition was promptly managed by upadacitinib, a selective Janus kinase (JAK) inhibitor. Physicians need not be overly concerned about this rare adverse reaction. JAK inhibitors may offer new treatment options with an advantage of rapid onset of action for patients experiencing LDE induced by biologic therapies for psoriasis.