Bartonella henselae infections
Bartonella henselae, acquired from cat scratches or bites, most often causes cat-scratch disease, a clinical diagnosis of an inoculation papule with tender regional lymphadenopathy that is usually self-limited but is treated with azithromycin to speed resolution, while disseminated, ocular, hepatosplenic, or immunocompromised disease needs doxycycline or azithromycin plus rifampin.
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What this article covers
- Overview
Bartonella henselae is a fastidious, gram-negative bacterium transmitted to humans by the scratch or bite of a domestic cat (especially kittens) and is the primary causative agent of cat-scratch disease.
- Epidemiology
Exposure to domestic cats, especially kittens, is the main risk factor for cat-scratch disease.
- Risk factors
Cat or kitten exposure with a scratch or bite is the dominant risk factor for cat-scratch disease.
- Pathophysiology
Inoculation at the scratch or bite site introduces the organism into the skin, producing a local papule that progresses to a pustule.
- Clinical features
Cat-scratch disease is recognized by its clinical triad: a papule or pustule at the site of a cat scratch/bite that appears 1-2 weeks after exposure, followed by tender enlargement of the regional…
- Differential diagnosis
Infectious mononucleosis: infectious mononucleosis causes generalized (not regional-inoculation-site) lymphadenopathy with pharyngitis, fatigue, and splenomegaly, with a positive heterophile antibody…
- Diagnosis
Cat-scratch disease is a clinical diagnosis, established by the triad of an inoculation papule, tender regional lymphadenopathy, and a history of cat or kitten scratch/bite exposure, and is confirmed…
- Management
First, for typical cat-scratch disease with bothersome lymphadenopathy, treat with azithromycin 500 mg PO on day 1, then 250 mg PO once daily on days 2 through 5 (5 days total), which hastens lymph…
- Complications
Parinaud oculoglandular syndrome (conjunctival granuloma with preauricular adenopathy).
- Prognosis
Uncomplicated cat-scratch disease is generally self-limited in immunocompetent hosts, with azithromycin hastening but not being required for lymph node resolution.
- Prevention
Avoid rough play with cats, especially kittens, that provokes scratching or biting, and wash any cat scratch or bite wound promptly with soap and water.
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