Case reports: Peficitinib efficacy in treating palmoplantar pustulosis induced by paradoxical reactions to golimumab in two rheumatoid arthritis cases.

A paradoxical reaction refers to a response opposite to the expected effects of drug therapy. Cutaneous paradoxical reactions, which occur with the use of immunosuppressive drugs, are believed to result from treatment-induced cytokine imbalances. These reactions can manifest as various dermatological conditions, including psoriasis and palmoplantar pustulosis. Currently, no established guidelines exist for reducing or discontinuing biologics in patients with rheumatoid arthritis who experience paradoxical reactions, posing a significant challenge for clinicians managing dermatitis and the underlying diseases. This case report presents two cases of patients with rheumatoid arthritis who developed palmoplantar pustulosis as a paradoxical reaction after treatment with golimumab, a tumour necrosis factor inhibitor. Both patients achieved remission of joint and skin symptoms following treatment with peficitinib, a Janus kinase inhibitor. To the best of our knowledge, this is the first report documenting the successful treatment of paradoxical reaction-induced palmoplantar pustulosis with peficitinib. These findings suggest that peficitinib could serve as an effective alternative when tumour necrosis factor inhibitors are no longer viable. Thus, peficitinib may be a potential therapeutic option for the management of rheumatoid arthritis patients with palmoplantar pustulosis.