Penicillamine‐induced elastosis perforans serpiginosa

A man in his 20s with Wilson disease presented with intensely pruritic papules on the posterior neck for 4 years. He had been receiving penicillamine therapy (750 mg/day) for approximately 10 years. Examination revealed multiple erythematous-to-violaceous hyperkeratotic papules (2–5 mm) coalescing into characteristic arcuate and serpiginous patterns on the posterior and lateral neck and upper back (Figure 1a). The lesions had been misdiagnosed as acne keloidalis nuchae, with no response to topical corticosteroids or cryotherapy. Histopathology showed orthokeratosis, marked acanthosis and thickened elastic fibres perforating the epidermis through epithelial channels (Figure 1b). Verhoeff–Van Gieson staining highlighted abnormal elastic fibre architecture, confirming elastosis perforans serpiginosa (EPS). The distinctive serpiginous morphology distinguishes drug-induced EPS from other posterior neck dermatoses and should prompt reevaluation and potential modification of penicillamine therapy. This research was not supported by any external funding sources. The authors declare no conflicts of interest related to this manuscript. Ethical approval was not required for this image-based case report. Written informed consent was obtained from the patient for the publication of clinical images and relevant clinical information. Data sharing is not applicable to this article as no new data were created or analysed in this study.