Paradoxical Reactions to Biologic Therapies in Patients with Plaque Psoriasis

Paradoxical psoriasis has been reported since 2003–2005. It is characterized by its occurrence independently of the underlying disease or the type of anti-TNF agent used, and it resolves once the treatment is discontinued. Unlike de novo psoriasis, paradoxical psoriasis is considered a side effect of TNF blockade. The pathophysiological mechanism involves an imbalance between TNF and type 1 IFN. The onset of skin manifestations can vary, ranging from 1 month to 10 years, with an average of 16.4 months. Approximately 2–5% of patients treated with TNF-alpha inhibitors develop paradoxical psoriasis. Females, particularly those with a personal or family history of inflammatory skin diseases, are more commonly affected. In addition, IL-17 and IL-23 inhibitors have been associated with worsening psoriasis, often triggering flares with altered psoriasis morphology.