Diseases & Conditions
Cat-scratch disease (CSD)
A mild illness following the scratch or bite of a kitten or cat that may involve a rash, caused by a small bacterium recently identified as Bartonella (formerly Rochalimaea) henselae. There are about 22,000 cases of cat-scratch disease (CSD) in the United States each year; three-quarters of the cases occur in children, more often in fall and winter. While the disease causes few problems in healthy youngsters, those with a weakened immune system can develop a lifethreatening infection.
The disease was first recognized in the 1950s, but the organism that causes it has only been recently discovered. The bacteria are transmitted between cats by the common cat fiea. The animal itself does not appear to be ill, and about 90 percent of cases are caused by kittens; the rest result from grown cats, dogs, and other animals.
Researchers still do not understand how the bacteria can live in the bloodstream, since blood is normally sterile and bacteria are usually killed by the immune system. While cats with the disease are not ill, many have large numbers of organisms in their blood.
The disease cannot be transmitted from one person to another, and it is not clear if one episode confers immunity.
About two weeks after a bite or scratch, the victim reports a red round lump at the site of infection and one or more swollen lymph nodes near the scratch, which may become painful and tender and occasionally discharge. Occasionally there is fever, rash, malaise, and headache. In most cases, symptoms disappear on their own.
CSD can be diagnosed by symptoms, history, and negative tests for other diseases that cause swollen lymph glands. In 1992 the Centers for Disease Control developed a blood test that detects antibodies to the bacteria. The test is available free to doctors and state health departments. Biopsy of a small sample of the swollen lymph node is not necessary unless there is an unusual symptom.
There are no antibiotics effective against CSD, although they are often prescribed for children with severe pain or swelling. A severely affected lymph node or blister may have to be drained, and a heating pad may help swollen, tender lymph glands. Acetaminophen may relieve pain, aches, and fever over 101°F. In most cases, the illness fades after one or two months, and the cat does not need to be destroyed.
A rare complication is ENCEPHALITIS, or catscratch disease of the brain, which appears about one or two weeks after the first symptoms of CSD. This usually resolves on its own without treatment. Signs of complications include: unusual spots or bruises on the skin, eye infections, unusual pain, high fever (over 103°F), stiff neck, severe headache, or severe vomiting.
Other than avoiding cats, there is no way to avoid the disease. However, cats only carry the infecting organism for a few weeks during their lifetimes, so the likelihood of being reinfected, or infected by just one pet in the home, is minimal. Children with weakened immune systems do not need to get rid of their cats, but they should try to avoid getting scratched. If a scratch does occur, it should be washed thoroughly with soap and water.