Recalcitrant Reactive Perforating Collagenosis Successfully Treated with Dupilumab: A Case Report.

Reactive perforating collagenosis (RPC) is the most common form of the perforating dermatoses, which include RPC, elastosis perforans serpiginosa (EPS), perforating folliculitis (PF), and Kyrle disease (KD). In RPC, altered collagen of the dermis is extruded through the epidermis, which can be misdiagnosed as other skin diseases, such as vasculitis or prurigo nodularis. RPC is associated with a number of conditions, including diabetes mellitus, hepatitis, and renal failure, and thus the management of the coexisting diseases is important. There is currently no standardized and effective treatment method for RPC. Here, we report a patient with RPC who was resistant to topical corticosteroids, oral loratadine, and thalidomide, and responded well to dupilumab without significant side effects.