By Gary M. White, MD
Non-descript papule 2-3 weeks after a cat scratch there.
Cat scratch disease is a feline-associated zoonotic disease with an annual US incidence estimated at 22,000 cases. It is most common in those less than 10 years of age. It represents an infection of the skin and regional lymph nodes by the gram-negative Bartonella henselae. Patients tend to have recently been bitten, scratched or licked by a kitten.
At the inoculation site, an inflammatory papulonodule forms. Several weeks later, painful lymphadenopathy develops. Encephalitis is a rare complication.
The standard diagnosis is serologic testing and may be considered in patients who present with adenopathy, fever, malaise and history of feline contact. The organism is difficult to culture.
An infectious disease specialist should be consulted. Usually no treatment is needed. Several antibiotics including ciprofloxacin, rifampin and tetracycline have been given. Fluctuant nodes may be drained. The patient does not appear to be contagious to others. There is some evidence that azithromycin hastens resolution of the adenopathy.
Primary lesions. Photos courtesy Roger Bitar, MD
Axillary adenopathy and fluid drained. Photos courtesy Roger Bitar, MD
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