Definition Cat scratch disease is an infection caused by the bacteria, Bartonella (bar-ton-el-ah) Henselae (hen-sel-ay).
What is going on in the body? People usually acquire Bartonella Henselae through small wounds, such as a cat scratch. Lymph nodes near the wound become swollen 1 to 7 weeks after exposure to the bacteria. Sometimes a skin papule, a small, solid elevation of the skin, will develop near the wound, too. In rare cases, infection can involve:
the eyes, known as conjunctivitis (con-junk-tiv-eye-tis)
the bones, called osteomyelitis (os-tee-oh-my-ah-lite-is)
the brain and spine, called aseptic meningitis (men-in-jie-tis) and encephalitis (en-sef-ah-lite-is)
Anyone with an abnormal immune system is likely to suffer more severe and complicated infections.
What are the signs and symptoms of the infection? Symptoms include:
swollen lymph nodes that can be tender, warm, and red
fever
loss of appetite
headache
fever
What are the causes and risks of the infection? Cats, especially kittens, are the most common source of infection for humans.
How is the infection diagnosed? Detecting antibodies, which are proteins produced by the body to fight germs and other foreign substances, to the bacteria in the blood is the usual method of diagnosis. A polymerase chain reaction test to identify the bacterial genes can also be used. In addition, using special techniques, the bacteria can sometimes be seen in biopsy specimens.
What are the risks to others? The infection is not spread person-to-person.
What are the treatments for the infection?
In healthy people, the infection usually goes away on its own in 2 to 4 months. In complicated cases, antibiotics, such as erythromycin or doxycyline, can be used.
Sometimes lymph nodes can be drained with a needle if they are very large and painful.
Antibiotics, such as azithromycin can be given to people with damaged immune systems, such as those with AIDS, or with widespread infection to get rid of the bacteria.
What are the side effects of the treatments? Side effects depend on the treatment.
What happens after treatment for the infection? Most healthy people recover without long-term effects.
Author: Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
