Rat Bite Fever
A previously healthy 36-year-old woman presented to the infectious diseases clinic with a 3-day history of fever, arthralgias, myalgias, and headache. She reported no recent travel or new sexual contacts. She stated that she had been bitten on her left hand by a pet rat approximately 10 days before presentation. Physical examination revealed a maculopapular rash on the feet (Panel A) and hands (Panel B), with pustule formation (Panel C). The right ankle, left knee, and left wrist were swollen and tender to palpation. The patient was admitted to the hospital, and empirical treatment with intravenous ceftriaxone was initiated. Cultures of a blood sample obtained at presentation were positive within 24 hours for Streptobacillus moniliformis, a gram-negative bacillus commonly found in the oropharyngeal flora of rats. A diagnosis of rat bite fever was made. With ongoing treatment, the fever and arthralgias resolved within 3 days and 6 days, respectively. The patient was discharged on hospital day 7 and completed a course of treatment with oral amoxicillin. She remained well at follow-up 3 months later.