Pembrolizumab-induced acquired perforating dermatosis

Immune checkpoint inhibitors such as the programmed cell death-1 (PD-1) inhibitors, pembrolizumab and nivolumab, are frontline treatments for several types of solid-organ malignancies. However, cutaneous adverse effects with PD-1 inhibitor therapy are common and include lichenoid reactions, eczema, vitiligo and bullous dermatoses. Perforating dermatosis is a rare condition characterised by the extrusion of degenerate materials from the upper dermis through the epidermis and has rarely been reported in association with PD-1 inhibitor therapy. Herein, we report the first case to our knowledge of acquired perforating dermatosis following treatment with pembrolizumab.