Off-label Use of Nemolizumab to Address Pruritic Skin Disease: A Case Series in Dermatomyositis Patients

Background: Dermatomyositis (DM) is an inflammatory myopathy frequently accompanied by pruritus, which can be severe, treatment-refractory, and associated with significant impairment in quality of life. Interleukin-31 (IL-31) has emerged as a key mediator of itch and has been implicated in the inflammatory pathways of dermatomyositis, suggesting a potential therapeutic role for IL-31 receptor blockade. Methods: We conducted a retrospective case series of 5 patients with dermatomyositis who were treated with nemolizumab for moderate-to-severe pruritus at Mount Sinai Dermatology between June 2025 and November 2025. Clinical response was assessed using patient-reported itch severity measured by numeric rating scale (NRS) scores and the Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI). Adverse events and short-term outcomes were recorded. Nemolizumab dosed according to approved atopic dermatitis/prurigo nodularis regimens (60 mg SC loading dose followed by 30 mg every 4 wk). Results: All patients experienced improvement in pruritus following nemolizumab initiation, with a reduction in itch observed in all cases and anecdotal improvement reported as early as 2 days in select patients. Improvements in cutaneous disease activity, as measured by CDASI, were also observed. Nemolizumab was well tolerated, with no serious adverse events. Conclusions: In this case series, nemolizumab was associated with rapid improvement in pruritus and cutaneous disease activity in patients with dermatomyositis, including those with longstanding or treatment-refractory disease. These findings support further investigation of IL-31 blockade as a targeted antipruritic strategy and cutaneous disease improvement in dermatomyositis through larger, prospective studies.