A pruritic psoriatic plaque develops at the donor site of an autologous skin graft: Koebner phenomenon

A 64-year-old man attended our dermatology clinic with a rectangular-shaped pruritic rash on the upper part of his right thigh and oval pink plaques on his right forearm. The patient said that the lesions had developed gradually over the previous few weeks. 3 months earlier, he had developed necrotising fasciitis of his right forearm after a fishing trip; tissue cultures had grown Vibrio vulnificus and an emergency fasciotomy had been done by plastic surgery colleagues. To repair the wound on his arm, a split-thickness rectangular patch of skin had been harvested from the upper part of the patient's right thigh and grafted onto the lesion on his right forearm. Both sites had healed well in the weeks following the operation but then the pruritic rashes began to appear. The patient was initially treated with topical sulfadiazine, which because it had no effect, prompted the referral to our clinic.