Pets have a way of getting into trouble with one another. And when the seemingly inevitable altercations ensue, fangs and fur can fly. Unfortunately, a great many of these cases end in abscesses. A bite-wound abscess forms when the body can’t remove infection, inflammation, and damaged cells fast enough after one cat bites another, but there are other kinds of abscesses. An abscess causes a painful lump at the bite site, fever, and tiredness until the infection is cleared up, which will require antibiotics and possibly surgery, depending on the size and severity of the infection.


A bite wound abscess occurs when the body’s immune system can’t clear a bacterial infection originating from a bite wound. As a result, the wound evolves into a pocket of pus, which is a liquid collection of inflammatory cells, bacteria, and damaged tissue. Bite wounds are especially predisposed to abscess formation due to the bacterial populations associated with the mouth.

But bite wounds are only one cause of abscesses. They can form in any part of the body and can result from bacterial infections of tooth roots and anal glands, for example.

Signs and Identification

An abscess usually manifests as a painful, fluid-filled lump under the skin or as a swelling over the face or adjacent to the anus (in the case of dental or anal gland abscesses, respectively). An owner may notice a small scab over a puncture wound near the lump, but sometimes an abscess isn’t noticed until it breaks through the skin, pus oozes from the site, and a foul odor is noted. Sometimes thick fur covers the entire area, making the initial wound, scab, or abscess difficult to find.

Sometimes a pet will develop a fever before the abscess is obvious, and the only change the owner will notice is that the pet’s appetite and activity level have decreased.

The clinical signs of abscesses may include:

  • Limping (if the wound is on or near a limb)
  • A lump or swelling
  • Redness of the skin surrounding a puncture wound or crust
  • Hair loss in a circumscribed (defined) area
  • An oozing sore of varying size
  • Purulent discharge (pus) from a wound
  • Licking or grooming a particular area excessively
  • Foul odor
  • Localized pain
  • Lethargy
  • Lack of appetite

The diagnosis of an abscess is usually made based on the obvious clinical signs listed above. Sometimes, however, a tiny bite wound in its earliest stage of infection may evade detection until it becomes a full-blown pocket of malodorous pus.

A veterinarian will often puncture a swelling with a sterile needle to obtain a sample of pus to positively identify the swelling as an abscess. Submitting a sample of the fluid to a microbiology laboratory for culture and sensitivity testing may be part of the diagnostic process in some cases.

In the case of dental abscesses, dental X-rays are required to positively identify the offending tooth root(s).

Affected Breeds

Any pet can get an abscess. Abscesses are by far most common in cats who have access to the outdoors and who play territorial games with their fellow felines. In this subset of the feline population, bite wounds sustained from other cats (and less frequently from encounters with wild animals) can develop into serious wounds that may require emergency veterinary care and result in prolonged healing times.


Once an abscess forms, it’s very difficult for the body to remove the material and fight the infection by itself. Indeed, an untreated abscess can sometimes lead to deeper and more widespread infection –– even sepsis (bacterial invasion of the blood that can cause death). Therefore, pets should be treated by a veterinarian as soon as the possibility of an abscess is identified.

Almost inevitably, antibiotics are employed to help fight the infection. Draining the abscess via surgical puncture and sterile drain placement is also a typical part of the treatment process. This frees the abscess pocket of its infectious material and promotes continued drainage as the antibiotics and antiseptics do their work. The drain is then removed within days of the procedure for healing to progress unfettered.

In the case of long-standing or especially deep/extensive abscesses, multiple surgical procedures may be required along with longer-term antibiotic administration. Hospitalization for intravenous fluids and antibiotics may also be indicated depending on the severity of the wounds.

In some cases, as when wounds occur on the extremities, antibiotics and continued wound care at home may be sufficient treatment. Routinely soaking or warm compressing the area with Epsom salts, if tolerable to the patient, can sometimes resolve the problem.

Dental abscesses almost invariably end in dental extractions due to the advanced nature of the periodontal disease than tends to precipitate them. Similarly, anal gland abscesses –– if recurrent –– may result in surgery to remove the affected anal gland(s).

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Other Considerations

One of the biggest concerns with bite wounds is the spread of infectious diseases like feline immunodeficiency virus (FIV, also known as feline AIDS), the feline leukemia virus (FeLV), and rabies. Only cats get FIV and FeLV, but rabies is a fatal virus that can be transmitted to humans. So it’s important to be aware that even if your cat’s rabies vaccination is up to date, state law may require your veterinarian to administer a booster vaccine if your cat has suffered a bite wound or a wound of unknown origin.

Any pet who is overdue for a rabies vaccine (or has never received one) should be vaccinated as soon as a veterinarian deems vaccination acceptable. This will inevitably depend on the presenting condition of the patient. It’s even possible that a pet will have to be quarantined and observed for signs of rabies. State and municipal governments generally have regulations regarding rabies exposure and quarantine procedures. Veterinarians are prepared to advise pet owners about laws that may apply.

Your veterinarian may recommend testing your cat for FeLV and FIV to determine whether infection may have occurred. Based on the risk for future exposure, vaccination against one or both viruses may also be recommended.

This article has been reviewed by a Veterinarian.