Causes

Cat scratch disease is caused by Bartonella henselae. The disease is spread through contact with an infected cat (a bite or scratch), or contact with cat saliva on broken skin or the white of the eye.

Symptoms

A person who has had contact with an infected cat may show common symptoms, including:

• Bump (papule) or blister (pustule) at site of injury (usually the first sign)
• Fatigue
• Fever (in some patients)
• Headache
• Lymph node swelling (lymphadenopathy) near the site of the scratch or bite
• Overall discomfort (malaise)

Less common symptoms may include:

• Loss of appetite
• Sore throat
• Weight loss

Exams and Tests

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 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. However, the Bartonella henselae IFA test is a very accurate way to detect the infection caused by these bacteria.

A lymph node biopsy may also be done to rule out other causes of swollen glands.

Treatment

Generally, cat scratch disease is not serious. Medical treatment is not usually needed. In severe cases, treatment with antibiotics such as azithromycin can be helpful.

In AIDS patients and other people who have a suppressed immune system, cat scratch disease is more serious, and treatment with antibiotics is recommended.

Outlook (Prognosis)

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.

Possible Complications

• Encephalopathy
• Neuroretinitis
• Osteomyelitis
• Parinaud's syndrome (granulomatous conjunctivitis with adenopathy)

When to Contact a Medical Professional

Call your health care provider if you have enlarged lymph nodes and you have been exposed to a cat.

Prevention

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.

Alternative Names

CSD; Cat scratch fever; Bartonellosis

References

Schutze GE, Jacobs RF. Bartonella species (cat-scratch disease). In: Long SS, ed. Principles and Practice of Pediatric Infectious Diseases. 3rd ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2008: chap: 160.

Slater LN, Welch DF. Bartonella, including cat-scratch disease. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009: chap 235.

Updated: 4/24/2012

Reviewed by: Linda Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington School of Medicine; 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. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.