Cat Scratch Disease

Alternative names:

cat scratch fever; CSD

Definition:

An infectious illness associated with cat scratches, bites, or exposure to cat saliva, causing chronic swelling of the lymph nodes (lymphadenopathy).

Causes, incidence, and risk factors:

Cat scratch disease is caused by a gram negative bacillus (a type of bacteria) presently referred to as CSD bacillus or Bartonella henselae. The disease is spread through contact with an infected cat, as a result of a cat bite or scratch, or contact with cat saliva on broken skin or the conjunctiva of the eye.

Lymph node swelling begins about 2 to 3 weeks after exposure and may persist for months. Swelling may occur at the site of the initial infection followed by enlarged lymph nodes along the lymph drainage route from the injury site. Occasionally nodes may form a fistula through the skin and drain. Cat scratch disease is possibly the most common cause of chronic lymph node swelling in children. Until now the disease often went unrecognized because of the difficulty in testing. Recently however, the B. henselae IFA test was shown to be highly sensitive and specific for the detection of infection caused by B. henselae and for the diagnosis of cat scratch disease.