Autoimmune Hemolytic Anemia in a Patient with Generalized Pustular Psoriasis Treated with Brodalumab: A Case Report

Psoriasis is a condition characterized by chronic inflammation of the skin, epidermal hyperproliferation, and dysregulated differentiation driven by acceleration of the tumor necrosis factor-alpha/interleukin (IL)-23/IL-17 axis. Herein, we report a case of generalized pustular psoriasis initially managed with etretinate, apremilast, and risankizumab in a Japanese man. Because of side effects, a therapeutic transition was made to brodalumab at 7 months after the initial consultation. His dermatological symptoms improved; however, hemoglobin concentration decreased to 7.6 g/dL after 4 months of treatment. Diagnostic investigation revealed warm autoimmune hemolytic anemia (AIHA). To our knowledge, this is the first report of AIHA during treatment with brodalumab for generalized pustular psoriasis. The etiological association between AIHA and psoriasis is unclear. Future studies should investigate whether AIHA accompanies pustular psoriasis or results from drug-induced AIHA secondary to brodalumab administration. Our findings suggest that the risk of AIHA in patients with psoriasis treated with brodalumab warrants careful consideration.