By Martha A. Simpson, D.O., M.B.A.
Associate Professor of Family Medicine
Ohio University College of Osteopathic Medicine

MOST VICTIMS OF CAT SCRATCH DISEASE RECOVER WITHOUT TREATMENT

Question: I took my son to the doctor because he had some swollen glands in his armpit for a few weeks and didn’t seem sick. The doctor thinks it might be cat-scratch fever and wants to do a biopsy of the lymph node before starting antibiotics. We had a kitten not too long ago but gave her away because she didn’t get along with the dog. Can you tell me more about what might be going on?

Answer: What you’re calling cat scratch fever goes by some other tongue-twisting names like “benign lymphoreticulosis” and “non-bacterial regional lymphadenitis” in doctor jargon. Today, I’ll simply call it cat scratch disease (CSD), which is a generally accepted term that’s “reader friendly.”

CSD is most common in young people under the age of 21. There are about 22,000 cases diagnosed in the United States every year. And, as the name implies, there is usually a history of a bite or scratch from a kitten or cat preceding the outbreak of the illness.

A person often acquires CSD when a cat infected with certain bacteria, usually Bartonella henselae, bites or scratches him or her. It can also be contracted indirectly if a person is bitten by a flea that has previously fed on an infected cat.

Typically, a small, brownish swelling containing pus – referred to as a “pustule” – develops over the site of the scratch or bite. This is followed in three to 10 days by swollen, painful lymph nodes as well as signs of generalized illness, such as fever, loss of appetite and fatigue.

You said that your son wasn’t sick now, but do you remember your son having any of these symptoms? This would be typical of CSD, because the lymph nodes usually remain after the signs of illness have resolved and the cat scratch is healed.

In fact, the painful lymph nodes can remain swollen for several weeks and become moveable and compressible. Eventually, the lymph nodes often spontaneously regress. This may take up to a month or more. There can be complications from CSD, especially involving the eyes and brain, but these are rare and usually there is full recovery.

Diagnosis of CSD is made when three of the following four criteria are met: history of a cat bite or scratch, positive skin test to CSD antigen or positive antibody test, all other explanations for the swollen lymph nodes have been ruled out, and characteristic lymph node lesions.

Generally, as your doctor suggests, a biopsy is done to confirm the diagnosis of CSD as well as rule out other causes of lymphadenopathy. The treatment for CSD is variable. About 90 percent of cases will resolve without treatment in six months.

There are two situations that call for antibiotic treatment. First, if there have been complications, a long course of antibiotics may be indicated. Second, if the patient has other health problems that increase the susceptibility to infection, antibiotic treatment is in order. Ask your doctor if one of these applies in your son’s case.

Finally, many people will probably be happy to learn that there is no need to get rid of the cat. That’s because it carries this infection for only a short period of time. It’s still, however, a good idea to keep the cat’s fleas under control. Also, you’ll be relieved to know that this disease is not spread from person to person.

Family Medicine® is a weekly column. To submit questions, write to Martha A. Simpson, D.O., M.B.A., Ohio University College of Osteopathic Medicine, P.O. Box 110, Athens, Ohio 45701, or via e-mail to readerquestions@familymedicinenews.org. Medical information in this column is provided as an educational service only. It does not replace the judgment of your personal physician, who should be relied on to diagnose and recommend treatment for any medical conditions. Past columns are available online at www.familymedicinenews.org.