Close to 90% of people can contract cat scratch disease. This disease is a bacterial infection that can cause swelling of the lymph nodes. The lymph nodes are round organs of the immune system. This disease is caused by the bacterium known as bartonella henselae - which is found in most parts of the world. A cat will usually be infected by the bacterium through fleas. The cat will then spread it to humans through licking, scratching, or biting.
In the United States close to 22,000 cases of cat scratch disease are diagnosed annually. Most patients are under the age of 21. This is because younger children have a higher risk of being bitten or scratched by cats because of the way that they play with them.
Cat Scratch Fever Symptoms
After a few days of being scratched, licked, or bitten by a cat a small bump or blister will form called an inoculation lesion. Most people will mistake this for a bug bite. They will usually appear on the hands, arms, head, or scalp. These lesions are usually not painful.
Within a couple of weeks the scratch or one of the lymph nodes close to the area where the lesion is will begin to swell and become tender to the touch. If the lesion is on the arm then the lymph nodes in the elbow or the armpit will begin to swell.
The swollen lymph nodes will begin to show more often in neck. However, if the lesion is on the leg it is more likely that the nodes located in the groin will swell. The skin around the swollen lymph nodes will turn red and become warm and may begin to drain pus after some time.
Swollen lymph nodes are the most common symptoms - but some people may experience other more general symptoms along with this. One third of people infect with cat scratch disease will experience fatigue, fever, headache, loss of appetite, rash, and sore throat. There are also certain people who will experience atypical cases of the disease. In these rare cases they will experience infections in the bones, liver, lungs, spleen, and joints.