Bullous Pemphigoid Possibly Induced by Deucravacitinib in a Patient with Psoriasis.

While bullous pemphigoid (BP) can be induced by various drugs, cases involving small-molecule inhibitors remain rare. We report the first case of BP occurring in a patient with psoriasis shortly after receiving deucravacitinib, a TYK2 inhibitor. Following treatment with methylprednisolone, minocycline, and ixekizumab, the lesions resolved within one month. Although the precise mechanism remains unclear, it may involve immunological drift and remodeling of skin immune microenvironment, which raises the need for clinical awareness regarding such reactions when using novel targeted immunomodulators.