Affected Animals:
Cats and other animals can develop an abscess. Unneutered male cats that spend any time outside are the most commonly affected with bite wounds.

Overview: There is a tremendous amount of bacteria in the mouth of a cat, and so when a cat bites another animal, the wound it leaves is very likely to become infected.  The holes created in the skin by the teeth tend to seal over quickly, trapping all the injected bacteria underneath.  When infection occurs, the wounded cat's body will send a large number of white blood cells called neutrophils to the bite wound to help kill the bacteria.  A painful abscess will form when the bacteria and neutrophils combine together in a pocket of pus that will appear at the wound site or just below it.

If the abscess is not able to drain to the outside surface of the cat's skin, the cat can experience a fever, anorexia, and other signs of illness.  If left untreated at this stage, the abscess will expand and burrow through the tissues until it ruptures through the overlying skin.  Generally, bite wound abscesses can be treated successfully with wound care and antibiotics.  A greater worry with fight wounds is that through them, cats can pass on life-threatening diseases -- such as the feline immunodeficiency virus, feline leukemia, and rabies.

Clinical Signs:
The clinical signs of an abscess vary, but typically there is a swelling or area of matted hair with some discharge coming from it.  Cat bite abscesses commonly appear at the base of the tail and on the animal's back, face, and legs.  The area is usually very sensitive and may be warm to the touch.  Cats that have significant infection will have a fever of 103.5 degrees Fahrenheit or higher, anorexia, lymphadenopathy, or swollen lymph nodes, and may show signs of depression.

Symptoms:
See clinical signs.

Description: When a cat bites another cat, its front canine teeth sink into the skin, depositing harmful bacteria.  Because the bite marks are usually small and seal closed quickly, the bacteria will be left buried underneath the skin where they can start an infection.

The body of a wounded cat will send a large amount of white blood cells called neutrophils to the bite wound to help kill the bacteria.  When a pocket of bacteria and neutrophils forms, it is called an abscess.  If the abscess is sealed over, then the cat can develop a fever and become very ill.  Once the abscess is opened up so that it can drain, though, the cat should begin to feel better. 

A bite wound from a cat can be severe and cause tremendous problems.  Life-threatening viruses such as feline leukemia and the feline immunodeficiency virus commonly are transmitted from one cat to another this way. 

Any cat bite should be cleaned thoroughly to prevent infection.  An attempt should be made to keep the skin lesions open for several days to allow the wound to heal from inside out.  Antibiotics also may be prescribed to eliminate the growth of bacteria.

If an abscess already has formed, the examining veterinarian will recommend the best course of treatment.  Some cases require sedation or anesthesia due to the pain associated with the wound and the type of procedure that needs to be performed.  Some abscesses expand so widely that when they rupture, they create a large defect in the skin tissue.  These may require some reconstructive surgery once the infection has been eliminated.

Diagnosis:
The veterinarian will obtain a thorough history of the cat's health from the owner, noting whether the animal goes outside often and its vaccination status.  A physical examination will reveal an abscess, which is either a firm or soft painful swelling, or an area of matted fur that may have pus oozing from it.  The veterinarian may extract a sample of the fluid from the wound and look at it under a microscope to positively diagnose an abscess.  Sometimes a culture will be taken to specifically identify the bacteria present and which antibiotics will be effective in killing them.

Prognosis:
The prognosis for a fight wound infection that properly is treated is excellent. However, cats that get into frequent fights are at high risk for contracting feline leukemia virus, feline immunodeficiency virus, and rabies, all of which are fatal.  There are vaccines that will help prevent FeLV and rabies, but there is currently no vaccine for FIV.

Transmission or Cause:
Fight wound infections are caused by a bite wound from another animal -- usually, another cat. Unneutered male cats are the most likely to develop an abscess because they tend to roam around outdoors and get into fights to defend their "territory."  There is a tremendous amount of bacteria in the mouth of a cat, so anytime a cat bites a human or another animal, there is a very good chance that the bite will become infected.  Cats with bite wounds or an abscess should be taken to a veterinarian; likewise, humans that receive a bite should seek immediate medical attention.

Treatment: The veterinarian will treat a cat bite wound by washing and rinsing it thoroughly with an antibacterial soap.  A hydrogen peroxide solution often is used to flush out and kill bacteria deep in the wound.  If there is an abscess that already has ruptured and is in the process of draining, the area should be clipped free of hair and cleaned out with an antibacterial soap.

For more severe abscesses, or abscesses that have not opened up and drained, surgical drainage is needed.  This procedure requires sedating the cat and surgically making a cut into the abscess to open it up and allow all the infective pus to drain.  Sometimes a temporary piece of material is left in the skin to allow the wound to drain for several days.  The owner usually is asked to move the material a little once or twice a day until the drainage stops.  The veterinarian usually will give an antibiotic injection and prescribe some for the owner to administer at home.

Owners should use caution when treating a cat with a bite wound or an abscess.  Some cats may try to bite if the area is extremely painful.  The veterinarian can assist with any problems that owners may have.
Severe wounds can leave a residual scar.  Reconstructive type surgery may be an option once the wound is free of infection.  This would reduce scar formation and speed the healing process.

Prevention:
The best prevention is to keep all cats indoors and prevent them from roaming and getting into fights.  All cats should be neutered so that they are less likely to roam around in search of a mate; neutering also may make cats less territorial.  Building fences can be helpful in preventing cats that persistently leave their homes from getting into fights outside of the property.