Case Report: Periungual Xeligekimab injection for refractory Acrodermatitis continua of Hallopeau.

This case report presents the novel and successful use of periungual Xeligekimab injections for managing refractory Acrodermatitis Continua of Hallopeau (ACH), representing the first documented application of this localized administration route for the IL-17A inhibitor. It contributes to the scientific literature by demonstrating a promising alternative therapeutic strategy for treatment-resistant ACH, highlighting the potential for enhanced local efficacy and minimized systemic exposure. The patient was a 36-year-old woman with a two-decade history of ACH affecting her digits, characterized by persistent periungual and subungual erythema, sterile pustules, significant nail plate dystrophy with thickening and fragmentation, and associated digital swelling, tenderness, and restricted motion. Prior therapies, including topical corticosteroids, phototherapy, and systemic tofacitinib, had proven ineffective. Diagnosis was confirmed clinically and supported by MRI, which revealed active bone marrow edema in the distal phalanges. The therapeutic intervention involved initial periungual injections of a diluted Xeligekimab formulation, which led to partial improvement. This was followed by a series of injections using undiluted Xeligekimab (100 mg/mL). This escalation resulted in marked clinical resolution: complete clearance of pustules and inflammation, healthy nail regrowth, and resolution of digital swelling and pain. Concurrently, the Dermatology Life Quality Index and pain scores dramatically improved, and follow-up MRI showed substantial resolution of the underlying bone marrow edema, confirming the treatment's efficacy on both cutaneous and deep osseous inflammation.