A 31-year-old woman comes to the office due to 3 days of rash on her left arm.  The lesion is mildly pruritic but not painful.  She is otherwise healthy and occasionally takes ibuprofen during the first few days of her menstrual period.  Temperature is 37 C, blood pressure is 110/75 mm Hg, and pulse is 95/min. The lesion is like a target sign known as erythema migrans. She recently went for an adventure trip in New Hampshire. The patient is diagnosed with Lyme disease.