Abstract: Biological agents have been widely used in the treatment of dematosis，however, they may induce other diseases or exacerbate pre-existing conditions during treatment, a phenomenon known as paradoxical reactions. This case report describes a patient with plaque psoriasis who developed a paradoxical reaction of generalized pustular psoriasis after treatment with adalimumab. The treatment was switched to guselkumab, and complete resolution of skin lesions was achieved at week 12 without adverse reactions. The patient is currently under ongoing treatment and follow-up.

Key words: guselkumab, adalimumab, generalized pustular psoriasis, paradoxical reactions