Acquired Reactive Perforating Collagenosis Treated with Upadacitinib: A Case Report and Literature Review

Acquired reactive perforating collagenosis (ARPC) is a rare perforating dermatosis linked to systemic diseases, with unclear pathogenesis and no standardized therapy. We report a 53-year-old male with ARPC who failed conventional treatments but improved rapidly with upadacitinib 15 mg/day for one month, followed by 15 mg every other day. After three months, most lesions resolved, leaving hyperpigmentation and scars. Literature review shows conflicting reports: one case of ARPC improved with upadacitinib, another developed ARPC during upadacitinib treatment for atopic dermatitis. Our findings suggest upadacitinib may be effective for ARPC, especially in pruritic patients, regardless of diabetes status.