Clinical background of patients with psoriasiform skin lesions due to tumor necrosis factor antagonist administration at a single center.

Paradoxical reaction (PR) occurs when a drug elicits a reaction contrary to what was expected. To clarify the clinical features and genetic background of individuals susceptible to PR, we analyzed the clinical course of patients in whom psoriatic eruptions worsened or newly developed during tumor necrosis factor (TNF) antagonist administration and the role of focal infections and genetic variations. Of 125 patients who received TNF antagonist therapy for psoriasis, acrodermatitis continua of Hallopeau (ACH), generalized pustular psoriasis (GPP), or palmoplantar pustular psoriasis (PPP), eight patients with PR were surveyed at our hospital Dermatology Department between 2010 and 2021. A survey was also done on six patients who received TNF antagonist therapy for Crohn's disease, rheumatoid arthritis, ankylosing spondylitis, and hidradenitis suppurativa and were referred to our department due to PR. Additionally, Sanger sequencing analysis was performed for all exons and flanking introns of IL36RN (interleukin 36 receptor antagonist), CARD14 (caspase recruitment domain-containing protein 14), and AP1S3 (adaptor-related protein complex 1 subunit sigma 3). The clinical assessment of the 14 patients demonstrated an average age at PR onset of 48.4 years, a male : female ratio of 5:9, and a mean administration period until onset of 9.2 months. The clinical types of PR were plaque psoriasis, PPP, GPP, pustulosis, acne, ACH, hair loss, and exacerbation of arthralgia. Histopathology revealed psoriasiform dermatitis in three patients. One patient continued TNF antagonist therapy. All of the patients with psoriasis and GPP had dental infections, suggesting that focal infection may be a risk factor of the development of PR following TNF antagonist therapy. Gene analysis demonstrated CARD14 gene variants associated with RA, CD, AS, or PPP in four patients. In addition, all of the patients with ACH and PPP experienced PR, suggesting that these diseases may predispose patients to PR to TNF antagonist therapy.