A 19-year-old woman came to our outpatient clinic with a rash on her upper left arm that she’d had for a month. Small pink and flesh-colored spots that first appeared over her left shoulder had spread down her arm and forearm to her wrist. The rash was initially scattered, but within a few weeks it had joined together to form a linear band. It was not itchy or painful.
Our patient had no changes to her fingernails, no contact with potential allergens, and no history of skin disease, atopy, or drug allergies. She was not taking any medication, but had received the second of 3 doses of the human papillomavirus (HPV) vaccine 2 months before she’d developed the rash. She had tried to treat the rash with an over-the-counter steroid cream, but it had not been effective.
On physical examination, we noted flat-topped, slightly scaly, pinkish papules that were about 3 mm in diameter and formed an interrupted linear pattern that extended down the patient’s left shoulder and arm, cubital fossa, and forearm to her wrist (FIGURE). There were no vesicles, pustules, erosions, ulcers, or excoriation. The rash was non-tender and Koebner’s phenomenon was absent.