CASE HISTORY: Background
This patient was an otherwise healthy 36-year-old male from Connecticut who began experiencing fevers and body aches. He reported that a week prior to the case visit he was bitten by an insect or spider on the back of his left knee, which did not bother him until two days later. He denied any hiking in the area, though had traveled to Massachusetts recently.
On day two of illness, he experienced increasing pain, warmth and swelling to the area. That day, he went to an urgent care clinic, where he was prescribed a course of 500mg of cephalexin 4 times a day for 5 days for presumed cellulitis. He began treatment but noticed no improvement. The next day he developed a fever of 103F, and began having body aches as well as nausea, vomiting, chills, and headaches. He ascribed his symptoms to a viral upper respiratory infection (URI), noting that his son was also sick and not vaccinated for COVID-19. On day two after presumed infection, his physical exam was only notable for an area of erythema to the left popliteal fossa, with warmth and induration, and consistent with cellulitis (Figure 1).