Apremilast for acquired reactive perforating collagenosis with metabolic and infectious comorbidities: a case report.

Acquired reactive perforating collagenosis (ARPC) is a rare disorder characterized by transepidermal expulsion of altered collagen, for which no standardized treatment is available. We present a case of a 67-year-old man with ARPC and significant comorbidities, including type 2 diabetes mellitus (T2DM), chronic hepatitis B (CHB), and impaired pulmonary function, who achieved rapid and substantial improvement in cutaneous lesions and pruritus after treatment with oral apremilast therapy. Notably, his comorbid conditions remained stable, and the clinical improvement persisted even after a seven-month drug-free follow-up period. This case highlights apremilast as a potentially effective and safe treatment option for ARPC, especially in patients unsuitable for conventional immunosuppressive therapy.