Cat scratch disease is a bacterial infection that can spread from cats to people.
Bacteria called Bartonella henselae cause cat scratch disease. Both adult cats and kittens can spread the disease. Cats may get the bacteria from fleas, which can carry the bacteria, but this hasn’t been proven. You can get the disease from an infected cat that scratches, bites, or even licks you. The fleas do not seem to spread the infection to people.
Sometimes there is no obvious cause of infection (for example, you may not have any scratches or bites or have not been near a cat). Rarely, the disease is spread by a dog or other animal.
Infected cats do not act sick. However, adults may have the following symptoms about a week after being scratched or bitten:
One to 4 weeks later, the bacteria travel to nearby lymph nodes, usually in the armpit, groin, or neck. The lymph nodes become large lumps that are usually painful and may get red.
Most of the time the body's defense system can clear up the infection without any treatment. Rarely the infection spreads to other parts of the body and becomes more serious. The infection is more likely to spread if your immune system is not working well (for instance, if you have been getting chemotherapy for cancer or have AIDS).
Your healthcare provider will ask if you have been around cats and been scratched, bitten, or licked. He or she will ask about your symptoms and examine you. Usually this is all that is necessary. If your provider is not sure of the diagnosis, you may have one or both of the following tests to look for the bacteria:
Usually no treatment is needed and you will get better without medicine. If your lymph nodes are very swollen and tender, or if the infection has spread to other parts of your body and become more serious, you may need antibiotics. In very severe cases you may need to be treated in the hospital.
Usually the effects of cat scratch disease last just a couple of weeks. The swollen lymph glands will gradually get smaller. They may not return to normal size for several months. Sometimes the infection causes the lymph nodes to become scarred and they never do completely return to their original size.
After having cat scratch disease once, you are very unlikely to ever get it again.
If you think you might have cat scratch fever, it is best to see your healthcare provider to decide if you need treatment.
The best way to avoid cat scratch disease is to clean any areas where cats scratch, bite, or lick you with lots of soap and water.
Cat scratch disease doesn't seem to be spread from person to person. If you got the disease from your pet cat, ask your veterinarian about getting treatment for the cat.
