Rat bite fever caused by a kiss

Nonspecific presentations, such as fever and rash, commonly present to the emergency department (ED). In such situations, a thorough history should be obtained, which includes any pet or animal exposure. When history elicits a recent rat exposure in combination with a patient presenting with fever and a rash, rat bite fever (RBF) should be considered. A bacterial illness caused by Streptobacillus moniliformis, RBF has a high mortality, and treatment should begin promptly once suspected. As its name suggests, RBF is most commonly caused by a rat bite, although any exposure to a rat or other rodent should raise suspicion for the illness. Here, we present an 8-year-old girl who came to the ED with complaints of fever, rash, and migratory arthralgias. The initial history and laboratory studies were unrevealing. Upon further questioning, the patient denied any bug or animal bites; however, she admitted to recently acquiring a new pet rat, which she let lick her mouth and lips. Rat bite fever was strongly suspected, and the patient was started on appropriate antibiotics in the ED. She made a full recovery within 48 hours of hospital admission. Although rare, RBF is a diagnosis that emergency physicians should be aware of because of its high mortality but favorable response to treatment. In addition, its incidence is increasing likely due to the increased popularity of rats as pets.