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Cat scratch disease is a bacterial infection that a person can get after being scratched, licked, or bitten by a cat or kitten.

In the United States, most cases happen in the fall and winter and usually affect kids, probably because they're more likely to play with cats and be bitten or scratched.

Bartonella henselae, the bacteria that cause this disease, live in infected cats' saliva but don't make the animals sick.  In fact, kittens or cats may carry the bacteria for months. Fleas spread the bacteria between cats.

Signs & Symptoms

The first sign of this infection is a blister or a small bump that develops several days after the scratch or bite and may resemble a bug bite. This blister or bump is called an inoculation lesion (a wound at the site where the bacteria enter the body). Lesions are most commonly found on the arms and hands, head, or scalp and usually are not painful.

Within a couple of weeks of a scratch or bite, one or more lymph nodes close to the area of the inoculation lesion will swell and become tender. (Lymph nodes are round or oval-shaped organs of the immune system that are often called glands.) For example, if the inoculation lesion is on the arm, the lymph nodes in the elbow or armpit will swell.

These swollen lymph nodes appear most often in the underarm or neck areas, although if the inoculation lesion is on the leg, the nodes in the groin will be affected. They range in size from about ½ inch to 2 inches in diameter and may be surrounded by a larger area of swelling under the skin. The skin over these swollen lymph nodes can become warm and red.

In most kids, swollen lymph nodes are the main symptom of the disease, and the illness often is mild. If kids have other general symptoms, they might include fever (usually less than 101°F or 38.3°C ), fatigue, loss of appetite, headache, rash, sore throat, and an overall ill feeling.

The swollen lymph nodes usually disappear within 2 to 4 months, although sometimes can last much longer. In rare cases, a person might develop other symptoms, including infections of the liver, spleen, bones, joints, or lungs, or a lingering high fever without other symptoms.

Diagnosis and Treatment

Doctors usually diagnose cat scratch disease based on a child's history of exposure to a cat or kitten and a physical examination. During the exam, the doctor will look for signs of a cat scratch or bite and swollen lymph nodes.

In some cases, doctors use laboratory tests to help make the diagnosis, including:

• blood tests and cultures to rule out other causes of swollen lymph nodes
• a blood test that is positive for cat scratch disease

Most cases do not need any special treatment. Antibiotics are sometimes used to treat a severe form of the disease. If your doctor has prescribed antibiotics, give them to your child on schedule and for as many days as prescribed.

Kids with cat scratch disease don't need to be isolated from other family members. Bed rest is not necessary, but can help if a child tires easily. If your child feels like playing, encourage quiet play while being careful to avoid injuring swollen lymph nodes. To ease sore nodes, give your child nonprescription medicines like acetaminophen or ibuprofen.

Contagiousness

Cat scratch disease is not contagious from person to person. The bacteria are spread by the scratch or bite of an infected animal, most often a kitten. They also can spread if the animal's saliva (spit) comes in contact with a person's eye or through broken skin. Sometimes multiple cases happen in the same family, usually through contact with the same infected animal.

Having one episode of cat scratch disease usually makes people immune for the rest of their lives.

Prevention

If you're concerned about cat scratch disease, you do not need to get rid of the family pet. The illness is not common and usually is mild, and a few steps can help limit your kids' chances of contracting it.

Teach kids to avoid stray or unfamiliar cats to reduce their exposure to sources of the bacteria. To lower the risk of getting the disease from a family pet or familiar cat, kids should avoid rough play to prevent being scratched or bitten. Have your family members wash their hands after handling or playing with a cat.

If your child is scratched by a pet, wash the injured area well with soap and water. Keeping the house and your pet free of fleas will reduce the risk that your cat could become infected with the bacteria in the first place.

If you suspect that someone caught cat scratch disease from your family pet, don't worry that your cat will have to be euthanized (put to sleep). Talk with your veterinarian about how to handle the problem.

When to Call the Doctor

Call the doctor whenever your child has swollen or painful lymph nodes in any area of the body. And always call your doctor if a child is bitten by an animal, especially if:

• the bite or scratch was from a cat and the wound does not seem to be healing
• an area of redness around the wound keeps expanding
• the child develops a fever that lasts for a few days after receiving the scratch or bite

If your child has already been diagnosed with cat scratch disease, call the doctor if your child has a high fever, lots of pain in a lymph node, seems very sick, or develops new symptoms.