Review Question - QID 216664

A 17-year-old girl presents to the emergency room due to a 1-day history of nausea, vomiting, and rash. She sustained a nose injury at soccer practice 3 days ago and nasal packing was placed. She reports she has not started any new medications recently. Her parents are concerned as she seemed more confused and unwell appearing today. The patient is generally healthy and does not take any medications. She is the leader of an outdoor expedition club and returned from a hike recently. She also just finished a course of antibiotics for a urinary tract infection last week. Her temperature is 102.3°F (39.1°C), blood pressure is 70/60 mmHg, pulse is 145/min, and respirations are 26/min. Her nasal packing from the initial visit is in place without further bleeding noted in the nares when the packing is removed. Examination of the skin shows diffuse erythroderma with findings shown in Figure A. The patient moves all extremities but does not follow commands. Her abdomen is soft and nontender. Pelvic exam is unremarkable with no notable discharge and no retained foreign body present. Which of the following is the most likely etiology of this patient's presentation?