Paradoxical Induction of Psoriasis and Lichen Planus by Tumor Necrosis Factor-α Inhibitors

Case 1. A 33-year-old white woman presented to our clinic with a new-onset psoriasiform pustular eruption involving her palms and soles 4 months after the initiation of adalimumab for Crohn's disease. Her medical history was significant for childhood atopic dermatitis and hidradenitis suppurativa, but she had no personal or family history of psoriasis. Topical corticosteroids including hydrocortisone 2.5%, triamcinolone 0.1%, fluocinonide 0.05%, and clobetasol 0.05% were used without improvement. The pustular eruption spread to her scalp, trunk, and proximal extremities, and her toenails developed onycholysis and dystrophy. Her adalimumab was withdrawn for 1 month due to suspicion of a paradoxical pustular psoriasis reaction. After 2 weeks off adalimumab, the pustular dermatosis had significantly diminished and her gastroenterologist changed her medication to methotrexate. Her eruption continued to clear over the course of the next 6 months.