Postoperative Skin Lesion After Knee Replacement

A 71-year-old woman with a history of intermittent generalized pruritus of unclear etiology and right knee osteoarthritis underwent total knee arthroplasty. She presented 8 weeks postoperatively with a 1-week history of scattered pruritic bullae around her incision site. She reported that the symptoms were unlike any rashes she had had before. She had no fever, knee pain, or lower extremity swelling. She was taking no medications and had no allergies. On examination, she was afebrile and well-appearing. Knee examination showed no effusion and normal range of motion without pain. Her incision was fully healed. Several 1- to 2-cm tense, fluid-filled bullae were present around the incision. There was no surrounding erythema or edema.