Cat scratch disease

It is more often observed in the autumn and winter months and in areas with humid climates. Cats under one year of age and especially strays have a greater degree of bacteremia and higher levels of antibodies against B. henselae. Transmission of B. henselae between cats is via the flea Ctenocephalides felis. This particular flea is not involved in the transmission of the disease from cats to humans and the disease is not transmitted from human to human.Most patients report contact with cats, but often do not recall being bitten. The incubation time from the moment of exposure to the appearance of the skin lesion is 7-12 days. The skin lesion appears in the form of a painless papule, which lasts 3 days to 3 weeks. Peripheral lymphadenitis follows after a lapse of one or more weeks.

Histological examination of the skin and lymph nodes initially shows lymphocytic hyperplasia and proliferation of arterioles. Later, granulomas containing scattered multinucleated giant cells appear. As the granulomas accumulate, the ensuing necrosis and invading neutrophils form stellate microabscesses.