Paradoxical reactions related to biological agents refers to the contradictory phenomenon that occurs during the treatment of biological agents, which is contrary to the treatment purpose or exacerbates the condition of the treated disease. The first biological agent reported to trigger paradoxical reactions is TNF-α inhibitors, which appeared firstly in the treatment of patients with rheumatic diseases, followed by psoriasis and inflammatory bowel diseases. Other types of biological agents such as interleukin (IL) 12/23 inhibitor ustekinumab and IL-17 inhibitors secukinumab and ixekizumab can also cause paradoxical reactions. The mechanism of paradoxical reactions related to biological agents in the treatment of psoriasis, the occurrence and clinical manifestations of common paradoxical reactions (paradoxical psoriasis, arthritis, inflammatory bowel disease, hidradenitis suppurativa, etc.), and the management principles of paradoxical reactions related to biological agents in the treatment of psoriasis are reviewed in this article.

Psoriasis; Biological agents; Paradoxical reactions; Tumor necrosis factor-alpha inhibitors; Interleukin-17 inhibitor; Interleukin-12/23 inhibitors