Cat Scratch Disease

Cat-scratch disease is a common, benign condition, most often caused by Bartonella henselae. It is transmitted by a bite or scratch of a kitten or a cat with fleas or occasionally, that of an other pet. Peak transmission is in the early fall or winter. The condition characteristically affects children and adults younger than 21 years. The vast majority of patients can recall a history of cat contact, but not all. Typically, within 2 to 3 days of inoculation, a papule develops and progresses to a vesicle, which is followed by proximal lymphadenopathy in about two weeks. Rarely, the primary lesion at the site of inoculation is pustular or nodular. In fewer than 6% of patients, the primary lesion is followed by a generalized macular-papular and morbilliform eruption. The involved lymph nodes are tender, often with overlying erythema; occasionally they can suppurate. The lymphadenopathy subsides spontaneously after several months. The diagnosis of cat-scratch disease is primarily clinical.

Photograph of cat scratch fever. Source: American College of Physicians

Differential Diagnosis:

Cat-scratch disease can be distinguished from cutaneous anthrax in the following manner.

Cat-scratch Disease

• Patient has had contact with kittens or cats with fleas
• Occurrence is in fall or winter
• Primary lesion is a papule or vesicle
• Lymph node histopathology is characteristic of the disease

Cutaneous Anthrax

• Ulcer with eschar is painless

• Ulcer and eschar are surrounded by characteristic non-pitting edema