Cat scratch disease is an infection with Bartonella bacteria that is believed to be transmitted by cat scratches and bites.
Cat scratch disease is caused by Bartonella henselae. The disease is spread through contact with an infected cat (a bite or scratch). It also can be spread through contact with cat saliva on broken skin or mucosal surfaces like those in the nose, mouth, and eyes.
A person who has had contact with an infected cat may show common symptoms, including:
Less common symptoms may include:
If you have swollen lymph nodes and a scratch or bite from a cat, your health care provider may suspect cat scratch disease.
A physical examination may also reveal an enlarged spleen.
Occasionally, an infected lymph node may form a tunnel (fistula) through the skin and drain (leak fluid).
This disease is often not found because it is hard to diagnose. The Bartonella henselae IFA blood test is an accurate way to detect the infection caused by these bacteria. The results of this test must be considered along with other information from your medical history, lab tests, or biopsy.
A lymph node biopsy may also be done to look for other causes of swollen glands.
Generally, cat scratch disease is not serious. Medical treatment may not be needed. In some cases, treatment with antibiotics such as azithromycin can be helpful. Other antibiotics may be used, including clarithromycin, rifampin, trimethoprim-sulfamethoxazole, or ciprofloxacin.
In AIDS patients and other people who have a weakened immune system, cat scratch disease is more serious. Treatment with antibiotics is recommended.
Children who have a normal immune system should recover fully without treatment. In people with a suppressed immune system, treatment with antibiotics usually leads to recovery.
Complications may include:
Call your health care provider if you have enlarged lymph nodes and you have been exposed to a cat.
Avoid contact with cats to prevent the disease. If this is not possible, wash your hands thoroughly after playing with a cat, avoid scratches and bites, and avoid cat saliva to reduce your risk of infection.
Reviewed By: Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.