Clinical Presentation of Rat Bite Fever

Diagnostic Features

The Centers for Disease Control and Prevention recommends considering rat bite fever in patients with a history of exposure and a rash that can involve the palms and soles, similar to Rocky Mountain spotted fever and secondary syphilis 1
A critical diagnostic clue is that the rash can involve the palms and soles, which should raise suspicion for rat bite fever when combined with appropriate exposure history 1
The rash may be nonspecific and can mimic numerous other conditions, including drug reactions, viral exanthems, endocarditis, and other tickborne illnesses, making diagnosis challenging 1
Patients may seek care before rash appears, similar to Rocky Mountain spotted fever, with initial presentation often including fever and systemic symptoms before rash development 2

The American Academy of Pediatrics and the Centers for Disease Control and Prevention note that patients may present with fever and systemic symptoms before rash development, which typically appears 2-10 days after the rat bite or exposure 2