Review Question - QID 214656

A 22-year-old man presents to the emergency department with ear pain. It started 2 days ago but has been gradually worsening. The patient also endorses difficulty hearing out of the affected ear. He is otherwise healthy and only takes albuterol for asthma. His temperature is 97.9°F (36.6°C), blood pressure is 121/81 mmHg, pulse is 77/min, respirations are 18/min, and oxygen saturation is 99% on room air. Physical exam is notable for the finding in Figure A. The patient is given a prescription for antibiotics and is sent home. He returns 6 days later with a worsening of his symptoms. He is sent home with a prescription for a higher dose of the same medication and returns for follow up with a resolution of his symptoms. Which of the following is the most appropriate explanation for this patient's clinical course?