Review Question - QID 214833

A 17-year-old girl presents to her primary care physician for a skin rash. She states that the rash is unsightly and embarrassing to the point that she refuses to wear short-sleeved shirts. She has a history of asthma and seasonal allergies and has a new sexual partner. She uses a rescue inhaler as needed and takes a combined oral contraceptive pill daily. Her temperature is 98.7°F (37.1°C), blood pressure is 119/72 mmHg, pulse is 73/min, respirations are 15/min, and oxygen saturation is 99% on room air. Physical exam reveals the finding in Figure A. Which of the following is the most likely diagnosis?