Reactive Perforating Collagenosis

Reactive perforating collagenosis is a rare skin disease that is has a characteristic transepidermal elimination of altered collagen through the epidermis. It occurs in two forms: an inherited form in childhood that is very rare and an acquired form in adulthood, more commonly found in patients with diabetes mellitus and end-stage renal disease. It is one of four perforating transepithelial elimination disorders. Perforating dermatosis is a skin disease that is characterized by the transepidermal elimination of material in the dermis that can be divided into two groups: primary and secondary. Primary perforating dermatoses include reactive perforating collagenosis, Kyrle disease, elastosis perforans serpiginous, and perforating folliculitis. Secondary perforating dermatoses was coined by Rapini in 1989 and is called acquired reactive perforating collagenosis. Commonly, patients will have hyperkeratotic papules on the extensor areas of extremities and hands, most likely over areas of superficial trauma. The lesions are very pruritic and can grow into large, umbilicated papulonodules with a central keratotic plug that relapse and remit over the span of the patient’s lifetime. Most cases are self-limited and do not require treatment. Patients can be treated with avoidance of superficial trauma and control of pruritus in most cases.