Prather Pediatric and Allergy Center - Ask Doctor Brent

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Title: Cat Scratch Disease New Insights

Category: Child Care


Cat scratch disease has been a common cause of swollen lymph nodes in children for years. There is no definite diagnostic test available and we are not even sure what bacteria or virus causes the lymph nodes to swell. A recent article in the New England Journal of Medicine may have some answers. A physician's survey was conducted in Kentucky among cat owners over a 13 month period. Patients, parents and matched controls who owned cats were tested. The serum of all these patients and their cats were tested for a bacteria called Rochalimaea henselae. Among 60 patients who were diagnosed with cat scratch disease, they were much more likely to have kittens in the home (with an odds ratio of 15) and they were much more likely to have been scratched or bitten by a kitten (with an odds ratio of 27). They were also much more likely to have had at least one kitten with fleas (with an odds ratio of 29). Serum from the patients who had diagnosed cat scratch disease were more likely to be positive for Rochalimeae hensalae than matched controls. Also the cats of the patients who developed cat scratch disease were much more likely to have antibodies to this bacteria. Specifically, 39 cats out of 48 tested among families that developed cat scratch disease were positive for the antibody as compared to 11 of 29 control cats. Among patients with a titer higher than 1 to 64 against R. henselae 38 patients out of 45 had such high titers and only 4 of 112 control samples. The conclusion of this study is that cat scratch disease seems to be strongly associated with owning a kitten. There is also a possibility that fleas may be involved in transmission of the disease. Work is being done to develop a blood test for the Rochalimaea antibody and may eventually be a help in diagnosing this confusing disease.

Most cases of cat scratch disease are fairly benign. The lymph nodes stay swollen for several weeks but eventually go down on their own. No definite antibiotic treatment has been proven to be helpful. When the lymph nodes become very fluctuant, (that is mushy and soft with pus) they may occasionally need to be drained surgically. This is a tricky job and should not be done lightly because of the risk of complications as the germs track out of the lymph node.

Other common symptoms found in cat scratch disease patients include fever, malaise (or being very tired and weak), a skin sore at the site where the cat scratched the patient, a drop in appetite, and less commonly conjunctivitis, rashes, and even encephalopathy. The swollen lymph nodes can be anywhere in the body but are most commonly under the armpits, under the neck, in the groin, and around the elbow.

If you feel that your child has cat scratch disease and the lymph node swelling is more than slight be sure to let your pediatrician or family doctor follow the condition with you to make sure that it heals and no complications occur. If necessary, they can refer to a sub- specialist such as an ENT or general surgeon.