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What is Cat Scratch Fever?

Tricia Christensen
Tricia Christensen
Tricia Christensen
Tricia Christensen

Cat scratch fever or cat scratch disease is a relatively rare illness caused by bacteria that cats may carry. The bacteria, Bartonella henselae, is carried by about 40% of cats at some point in their lifetimes, and is transmitted to humans through the scratch or bite of an infected cat, hence its name. It is not known whether a fleabite from an infected cat could transmit the disease, but it is known that kittens are more likely to transmit the disease than are adult cats.

Most people who get cat scratch fever will have an uncomplicated illness that resolves on its own in a few weeks. Symptoms include swelling of the lymph nodes, redness or swelling at the site of the scratch or bite, fever, general achiness, and feeling tired. Generally, an uncomplicated case is not treated because often it is not reported and may be mistaken for the flu.

Young kittens are more likely to transmit cat scratch fever than adults.
Young kittens are more likely to transmit cat scratch fever than adults.

However, some people run a higher risk of complications from cat scratch fever. Very young children and those with compromised immune systems from autoimmune diseases like HIV or lupus may have complications. These include significant and persistent swelling of the lymph nodes, very high fever, encephalitis, and swollen lymph nodes near an eye, which causes pinkeye-like symptoms. In rare cases the complications — especially from encephalitis — may lead to convulsions.

An adult cat.
An adult cat.

One should always wash a bite or scratch from a cat with warm soapy water as this may prevent getting any animal borne illnesses. Further, one should watch the scratch or bite over the next few days. If it becomes swollen, turns red or has pus, a medical professional should examine it. If you note the symptoms listed above, you should also contact a doctor.

Cat scratch fever may cause swollen lymph nodes.
Cat scratch fever may cause swollen lymph nodes.

It has until recently been quite difficult to test for cat scratch fever. Naturally if a person remembers being scratched and can show an infected scratch, this diagnosis is often deduced. Since physicians now have identified the bacteria that causes the disease, blood tests, or in severe cases, a small tissue extraction from a swollen lymph node can correctly identify the presence of Bartonella henselae.

People may experience high fever after a cat scratch.
People may experience high fever after a cat scratch.

Patients who begin to show more significant reactions to the bacteria may be treated with antibiotics. People with suppressed immune systems are generally routinely given antibiotics to prevent severe complications. Many recover from the illness with no need for treatment beyond a few days rest.

An interesting new theory regarding cat scratch fever is that it may be responsible for many of the cases of chronic swollen lymph nodes in children. Long after a child has fought off the bacteria, he or she may still have swollen lymph nodes, which can be painful. Often antibiotics help to reduce this swelling.

Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent WiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

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Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent WiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

Learn more...

Discussion Comments

anon193698

my doctor says it's paracetamol, but I have been using this for a long time and no reaction. Recently I have been scratched by a kitten. The claw seemed to pinch me in my vein on the joint in my arm. I didn't take notice but came up with a welt running down the vein. Although I understand what the doctor said, but my top part of arm got sore and my lymph nodes under my arm were sore. Please advise.

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    • Young kittens are more likely to transmit cat scratch fever than adults.
      Young kittens are more likely to transmit cat scratch fever than adults.
    • An adult cat.
      By: Eric Isselée
      An adult cat.
    • Cat scratch fever may cause swollen lymph nodes.
      By: Klaus Eppele
      Cat scratch fever may cause swollen lymph nodes.
    • People may experience high fever after a cat scratch.
      By: unpict
      People may experience high fever after a cat scratch.
    • Very young children may run high fevers with cat scratch fever.
      By: robhainer
      Very young children may run high fevers with cat scratch fever.
    • Most people who contract cat scratch fever will have an illness that resolves on its own.
      By: Yeko Photo Studio
      Most people who contract cat scratch fever will have an illness that resolves on its own.
    • People can become infected with cat scratch fever through a scratch or bite.
      By: Julija Sapic
      People can become infected with cat scratch fever through a scratch or bite.
    • Cat scratch fever may be a cause of chronic swollen lymph nodes in children.
      By: JackF
      Cat scratch fever may be a cause of chronic swollen lymph nodes in children.