Reactive Perforating Collagenosis; An Uncontrolled Pruritus That Left You Scratching Your Head

Acquired perforating collagenosis is a rare disease of altered collagen formation that is extruded through the epidermis. It is most commonly seen in patients with microvascular disease including longstanding diabetes and chronic kidney disease (CKD). Due to the rarity of the disease, no large randomized clinical studies have been performed to determine the most efficacious method of treatment. Therefore, most of the knowledge available for treatment is secondary to the information collected through case reports, case series, and retrospective analyses. In this report, we present the case of a 68-year-old male with history of stage IV CKD who presented with a severe skin rash that was present over his body, including the chest, arms, back, neck, and buttocks. It did not involve the mouth, legs, palms or soles of the feet. He did not have a significant history of diabetes and had been placed on steroids with the concern that this rash may have been secondary to a drug reaction, erythema multiforme, or bullous pemphigoid. Two skin biopsies were performed as the patient was not responding to systemic and topical steroid or oral antibiotic therapy. The final biopsy ultimately revealed a diagnosis of acquired perforating collagenosis. This is unusual in our case because although our patient had advanced CKD, he was not on dialysis, and had no significant longstanding history of diabetes. Additionally, as the prevalence of CKD is increasing in the population, it becomes more pertinent for providers to be aware of dermatological conditions associated with advanced CKD. This case report seeks to raise awareness of this disease. Furthermore, as the initial skin biopsy was unrevealing, this case also emphasizes the importance of repeating a biopsy to reduce the chance of sampling error.