Development of a psoriatic arthritis – like presentation under anti – IL-13 therapy with tralokinumab for atopic dermatitis

Objectives Dual blockade of IL-4 and IL-13 in atopic dermatitis (AD) has been associated with activation of the IL-23/IL-17 axis, potentially leading to paradoxical psoriasis and psoriatic arthritis (PsA)-like presentation. However, the specific cytokine responsible for these reactions remains unclear. We report a case series of PsA-like presentation following treatment with tralokinumab, an anti-IL-13 monoclonal antibody used for AD. Methods We identified four patients who developed a PsA-like presentation affecting the joints, entheses, and, in some instances, the skin, following tralokinumab initiation for AD. Clinical features, laboratory findings, imaging results, and treatment outcomes were assessed. Results Among 139 patients treated with tralokinumab across two large UK referral centers, four developed new-onset PsA-like presentation with inflammatory arthritis and enthesitis that emerged after tralokinumab initiation. All four had previously failed dupilumab therapy. Skin biopsies and joint imaging confirmed PsA-like features. Symptoms began weeks to months after starting tralokinumab and resolved following treatment withdrawal or modification. Conclusion To our knowledge, this is the first case series documenting arthritis and enthesitis associated with anti-IL-13 therapy, suggesting a potential pathogenetic role of IL-13 inhibition in the development of PsA-like presentation. These findings warrant further investigation.