Cat Bites and Scratches

Cat bites and scratches are notorious for becoming infected. The most common sequel is an infection of skin (dermatitis) or underlying tissues (cellulitis) caused by a mixture of pathogens that are introduced during the scratching or biting episode. Often Pasteurella bacteria are isolated from these infected wounds. Signs of infection may include swelling, redness, pain and discharge.

Another bacterial agent termed Bartonella henselae is responsible for cat scratch fever disease in humans, but this agent is not known to cause illness in dogs. In people, the disease is generally mild, but signs can mimic lymphoma cancers and other serious diseases. Rarely, complications such as encephalitis may occur, and immune compromised patients may develop vascular lesions or life threatening complications such as endocarditis.

Because some of the bacteria carried by cats and introduced into deep scratches and bites can make people seriously ill, deep puncture wounds from bites often result in human hospital admission and intravenous antibiotic administration. If a family member has a cat bite wound, these should be brought to the attention of your family physician or emergency physician promptly.

There is a screening test available for practitioners in order to screen cats for Bartonella. Cats do not generally show disease, though a few cases with vegetative endocarditis of the heart have tested positive for the agent. Usually the test is used to detect carriers and based upon the geographic location, between 5-60 percent of cats will respond with a positive test. Transmission between cats is thought to be via fleas, and young flea bitten cats are often infected.

Because disease agents can travel from a local wound to the surrounding tissues and even get into the bloodstream, deep scratches and bites can have serious consequences. Bites particularly can lead to abscesses, or pus pockets in the tissues in the vicinity of the wound. Treatment for cat bite and scratch wounds in dogs is usually supportive, consisting of cleaning the wound and if swelling or pain/redness/pus discharge are noted in deeper wounds, a swab for a bacterial culture and sensitivity test will be taken by the veterinarian to assist with antibiotic selection. Serious face, mouth or nose wounds may also cause pain and even interfere with appetite and in those cases, some pain medication may be prescribed. Sometimes warm compresses or other nursing care procedures are recommended.

A professional assessment should be sought if in doubt about the depth of the wound, if it appears to be infected, or signs of systemic illness such as loss of appetite, lethargy, fever etc. are noted. If signs are progressive, it is wise not to wait for veterinary evaluation and treatment—contact your local veterinary facility promptly.