# Effectiveness of baricitinib in acquired reactive perforating collagenosis: a case report

## TL;DR

This case report shows that baricitinib can effectively treat acquired reactive perforating collagenosis, a skin condition resistant to other therapies.

## Contribution

The report presents baricitinib as a novel and effective treatment option for ARPC.

## Key findings

- Baricitinib therapy led to gradual improvement in ARPC symptoms.
- The patient experienced no adverse effects during treatment.
- Histopathological findings confirmed the ARPC diagnosis.

## Abstract

Acquired reactive perforating collagenosis (ARPC) poses a clinical challenge with an unclear pathogenesis. This disease has been frequently proven resistant to immunosuppressive treatments, significantly affecting the quality of life of patients. In this report, we highlight the efficacy of baricitinib as a viable option for maintenance therapy in ARPC.

An 81-year-old woman presented to our hospital with recurrent pruritus and cup-like ulcerated lesions on her trunk and limbs persisting for 1 year. She exhibited limited response to oral antihistamines and topical steroids. Past medical history revealed a prolonged history of coronary heart disease and type 2 diabetes spanning several years to decades. Histopathological examination revealed cup-shaped depressions filled with necrotic inflammatory debris. In the dermis, a mixed inflammatory infiltrate composed of lymphocytes and histiocytes was observed. Van Gieson staining indicated the elimination of fibrous tissue extending from the dermis into the epidermis. Consequently, a diagnosis of ARPC was established. Due to the inadequate response to conventional treatments and the severe itching, we initiated baricitinib therapy for ARPC, resulting in gradual symptom improvement. Follow-up assessments showed no adverse reactions and normal laboratory findings.

The case report suggests that baricitinib might offer significant therapeutic benefits for ARPC.