Cat Abscesses: Causes and Treatment

In cats, abscesses or pus ulcers are particularly common in the skin, jaw, or organs such as the liver. This is a form of inflammation in which pus forms in tissue cavities and this is encapsulated from the surrounding tissue by connective tissue. The encapsulation distinguishes an abscess from a so-called empyema, which describes an accumulation of pus in physiological cavities such as joint cavities or hollow organs (e.g. uterus). Pus arises from the melting of cells in the course of the inflammation, which in cats often comes about as a result of bacterial infections in the course of biting injuries. Sterile, non-infectious abscesses are less common.

How Does an Abscess Develop in Cats?

Although inflammatory processes can be very painful, the body has a specific goal with this symptom. To combat bacterial infection, important cells of the immune system initially penetrate the target tissue. These neutrophils fight the bacteria, for example by ingesting them. The tissue then melts and becomes encapsulated by the formation of connective tissue. The latter protects the surrounding tissue from infection and prevents the bacteria from rising further.

In general, abscesses in cats can develop in any organ. The bacteria that are often involved in cats include environmental germs such as staphylococci. However, bacteria such as clostridia or Escherichia coli can also lead to abscesses in cats. These germs usually enter the cat’s body through the following entry ports:

• About open wounds: In free-roaming cats, the most common cause of abscesses is a bite injury in the context of turf wars. In addition, the bacteria can also penetrate the skin through other open wounds, for example through open bone fractures, cuts, or foreign bodies.
• Via the bloodstream: in cats and other pets, blood poisoning (sepsis) can result from small wounds or umbilical infections in kittens. Through the bloodstream, the bacteria can then colonize the entire body and lead to abscesses in internal organs (e.g. in the liver)
• As a result of dental diseases: Cats often suffer from inflammation of the gums (gingivitis) or inflammation of the gum tissue (periodontitis). These inflammatory processes gradually lead to micro-injuries to the mucous membrane and tooth structures. Since there are a large number of bacteria in the mouth, they quickly reach the cat’s jaw via the tooth root.
• By inhaling foreign bodies: Sometimes people who walk outdoors inhale grasses or awns, which get stuck in the lungs through their barbs. Since these are not sterile and carry a wide variety of environmental germs, they can lead to abscesses in the lungs.

How do I recognize an abscess in my cat?

An abscess can be recognized by the following features:

• Reddening of the tissue.
• Swelling (not visible in abscesses of internal organs).
• Painfulness and tenderness: Cats often react to pain through behavioral changes such as aggressiveness, increased rest, or unwillingness to eat. However, some cats do not let their pain show for a long time because their natural instinct for survival means that they only allow weakness to be felt late.
• Formation of pus: the consistency of the yellowish liquid can vary between liquid, waxy and crumbly.
• Sometimes the abscess cavity ruptures, leading to the formation of inflammatory ducts and crevices (fistulas). If it then comes to bacterial blood poisoning (sepsis), fever and a deteriorated general condition follow.

Diagnostic options

If your cat limps, eats poorly or if you can even feel an increase in size, this should be clarified by a veterinarian. The most important differential diagnosis of an abscess is a tumor, which is also expressed by an increase in size. The following diagnostic measures are helpful in finding an abscess or differentiating a tumor:

• During the inspection, the vet looks for further clues on the surface of the cat’s body, such as bite marks or signs of inflammation such as pus.
• Imaging methods such as ultrasound or X-rays are suitable for finding abscesses inside the body.
• Inflammation parameters can be measured using a blood test.

How can an abscess in cats be treated?

If an abscess threatens to burst, it must be artificially opened under aseptic conditions to prevent bacterial blood poisoning. This is usually done using a puncture needle and simultaneous ultrasound control. Since this procedure is painful and requires the cat to hold still, the dissection of an abscess in cats is often performed under anesthesia or local anesthesia. The abscess is then completely emptied and then cleaned. Abscesses of internal organs also require what is known as omentalization, in which, for example, the abdominal mesh is placed in the abscess cavity for better wound healing for drainage. The cats are then given pain medication and, if necessary, antibiotics.

What is the prognosis?

Abscesses in cats can vary in the course depending on the location, size, and type of bacterium. In general, a large abscess tends to break open and, accordingly, is more likely to lead to life-threatening blood poisoning. The formation of fistulas or the occurrence of an abscess in hard-to-reach places (e.g. in the pelvic cavity or in the upper jaw) make therapy and thus the prognosis more difficult.

How can abscesses in cats be prevented?

To prevent abscesses from forming in cats, early wound hygiene is of great importance. This can be done as follows:

• Often only two bite marks are visible after territorial fights. However, since animals always bite with all four canine teeth, the opposite side of the body part should always be searched for the other two bite marks.
• Before starting the actual wound hygiene, it is important to wash and disinfect your own hands. If medical gloves are available in the household, they can be put on to prevent further contamination.
• For thorough wound hygiene, it is advisable to carefully shear the wound and the surrounding skin area.
• The wound should be cleaned using sterile saline or cooled boiled water.
• Aseptic solutions can be carefully applied to the wound in a jet or with a swab for disinfection.
• The wound should not be covered to allow it to dry and heal.
• The wound should be inspected from time to time for the next few days. In the event of deterioration, however, it is advisable to have the event checked by a veterinarian.