Clinical management of paradoxical psoriasiform reactions during TNF- α therapy.

There have been reports of paradoxical induction or worsening of psoriasis during treatment with tumor necrosis factor (TNF) α agents (infliximab, etanercept, adalimumab, and certolizumab). It has been hypothesized that an imbalance between TNF-α and interferon α might have a role in the etiology and pathogenesis of these reactions. Paradoxical psoriasiform reactions can be divided clinically into de novo psoriasis and exacerbation of preexisting psoriasis. The first, which is more common and more extensively described in the literature, occurs in patients without a history of psoriasis who are receiving TNF-α therapy for another inflammatory disorder. The second can occur with or without changes in the morphology of the lesions. In this article, we review the literature on the clinical and histologic features of paradoxical psoriasiform reactions, analyze their clinical course and treatment, and propose a clinical management model for use in routine practice.