What is cat scratch disease (CSD)?

Definition

Cat scratch disease (CSD) is a bacterial infection caused by a scratch or bite from a cat or kitten (and sometimes from a dog). The infection usually heals without treatment, but it can become a potentially serious condition that requires care from a doctor.

Causes

The bacteria that cause cat scratch disease are found in fleas. They are passed to cats through flea bites, then to humans through a cat scratch or bite. Children age ten years and younger are most often affected because they are most often bitten or scratched by a cat during play.

Risk Factors

Factors that increase the chance of getting cat scratch disease include a recent bite or scratch from a cat or kitten and a weakened immune system, which also increases the chance of serious complications from the disease. People with weakened immune systems include babies, the elderly, organ transplant recipients, and individuals with human immunodeficiency virus (HIV), acquired immunodeficiency syndrome (AIDS), or cancer.

Symptoms

Symptoms of cat scratch disease include a crusting sore or blister that develops over the scratch or bite site; swollen, painful lymph nodes; low-grade fever; and flulike symptoms, such as weakness, nausea, chills, loss of appetite, and headache. If the patient does not begin to get well within a few days, he or she may develop complications, such as a high fever or pneumonia. Severe cases have caused infections of the brain (encephalitis), hepatitis, and even death.

Screening and Diagnosis

A doctor will ask about symptoms and medical history and will perform a physical exam. The doctor will probably be able to diagnose the disease based on painful, swollen lymph nodes and the patient’s knowledge of being bitten or scratched. However, the doctor may order a blood test, especially if the diagnosis is not clear from the exam and medical history.

Treatment and Therapy

Treatment options include rest and nonprescription pain relievers such as acetaminophen. If a lymph node is swollen or painful, the doctor may drain it to relieve pain and help it heal. To do this, the doctor will put a hypodermic needle into the swollen node. Fluid inside the node will then drain out through the needle.

Cat scratch disease usually clears up without treatment, but if the lymph nodes stay painful and swollen for more than two or three weeks, or if the patient gets very ill, the doctor may prescribe antibiotics for treatment. Antibiotics may also be prescribed for those with HIV infection or other immunocompromising diseases.

Prevention and Outcomes

The best prevention against cat scratch disease is to avoid being scratched or bitten by a cat or dog. If bitten or scratched, one should wash the bite or scratch immediately with antiseptic soap and hot water. Also, one should keep pets free of fleas.

Bibliography

Chomel, B. B. “Cat-Scratch Disease.” Revue Scientifique et Technique 19.1 (2000): 136–50. OIE: World Organisation for Animal Health. Web. 29 Dec. 2015.

Conrad, Dennis A. “Treatment of Cat-Scratch Disease.” Current Opinion in Pediatrics 13.1 (2001): 56–59. Print.

Dehio, Christoph. “Cat Scratch Disease, Bacillary Angiomatosis, and Other Bartonelloses.” Schaechter's Mechanisms of Microbial Disease. Ed. N. Cary Engleberg, Victor DiRita, and Terence S. Dermody. 5th ed. Baltimore: Lippincott, 2013. 287–91. Print.

Lamps, Laura W., and Margie A. Scott. “Cat-Scratch Disease: Historic, Clinical, and Pathologic Perspectives.” Supp. to American Journal of Clinical Pathology 121 (2004): S71–80. Print.

Reynolds, Mary G., et al. “Epidemiology of Cat-Scratch Disease Hospitalizations among Children in the United States.” Pediatric Infectious Disease Journal 24.8 (2005): 700–704. Print.

Windsor, Jeffrey J. “Cat-Scratch Disease: Epidemiology, Aetiology and Treatment.” British Journal of Biomedical Science 58.2 (2001): 101–10. Print.