SHM Converge Scientific Abstract ePoster Gallery-Rat Bite Fever: A Rare Cause of Rash on the Palms and Soles

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This case describes an otherwise healthy woman in her 30s–40s who presented with one week of subjective fever/chills, painful pustular lesions on the tongue and elbows, and severe polyarthralgias involving the shoulders, wrists, back, and ankles. Her rash later spread to the palms and soles, prompting evaluation for more common causes such as hand-foot-mouth disease, disseminated gonorrhea, syphilis, RMSF, coxsackie virus, reactive arthritis, and palmoplantar pustulosis.<br /><br />Initial treatment at an outside ED with steroids helped her pain somewhat. On further history, she reported a recent pet rat bite, which led to the correct diagnosis of rat bite fever. She had no significant travel, IV drug use, farm animal exposure, or insect bites. Exam showed a fatigued woman with a healing tongue ulcer and scattered pustular lesions on the palms, arms, feet, legs, and face, plus wrist and ankle tenderness without clear joint swelling or erythema.<br /><br />Workup showed marked leukocytosis with neutrophilic predominance and very elevated CRP, but blood cultures were negative. Testing for gonorrhea/chlamydia, syphilis, HIV, enterovirus, HSV, VZV, tick-borne disease, and rheumatologic conditions was unrevealing. She was empirically treated with ceftriaxone and doxycycline, with partial improvement. After the rat exposure was discovered, doxycycline was extended and her symptoms eventually resolved.<br /><br />The discussion emphasizes that rat bite fever is a rare zoonotic infection caused by Streptobacillus moniliformis, classically presenting with fever, rash, and polyarthralgias. Because the organism is difficult to culture and mortality can be significant, clinicians should consider it early when fever and rash follow rat exposure. Penicillin is standard therapy, with doxycycline as an alternative. The case highlights the importance of revisiting the history when the initial workup is negative and recognizing uncommon diseases that mimic more common infectious or inflammatory conditions.

Asset Subtitle

Raymond Lay

Meta Tag

Author List Diego Suarez, Raymond Lay

Category Clinical Vignettes

Concept Rat Bite Fever

Concept Streptobacillus moniliformis

Concept Zoonotic Infection

Concept Palmoplantar Rash

Concept Exposure History

Distinguished Non-Finalist

Presenter Organization Mayo Clinic Rochester

Presenting Author Raymond Lay

Track Adult

Keywords

rat bite fever

Streptobacillus moniliformis

fever and rash

polyarthralgia

pustular lesions

rat exposure

zoonotic infection

palms and soles rash

doxycycline treatment

negative blood cultures

Rat Bite Fever

Streptobacillus moniliformis

Zoonotic Infection

Palmoplantar Rash

Exposure History