Ocrelizumab‐induced psoriasiform dermatitis: Case reports and review of the literature

Abstract Ocrelizumab (OCR) is a humanized anti‐CD20 monoclonal antibody approved for treating multiple sclerosis. We present three patients who developed psoriasiform dermatitis (PsD) during OCR treatment and a review of the cases published to date. We hereby report the first exclusive fingernail involvement. Most of the cases had a mild skin involvement and only one case required OCR discontinuation. No association with arthritis, personal or family history of psoriasis was found. Data compiled suggests that PsD tends to appear within the first year of treatment. There are few studies focusing on B‐lymphocytes in psoriasis and several hypotheses attempt to explain their role. The most widely accepted is the depletion of regulatory B‐lymphocytes with immunomodulatory function through interleukin‐10. However, the exact mechanism by which this occurs with OCR remains unclear and the presented case of anti‐CD20‐induced PsD highlights the importance of continuous monitoring of new treatments in terms of dermatological side effects and the induction of skin diseases, in particular psoriasis. There is also a need to inform the professional community about the possibility of psoriasis in patients with multiple sclerosis and the consequences of this condition.