What causes abscess in cats

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Cat with facial abscess
Cat With Facial Abscess

Cats often develop abscesses but there are several different reasons for why one of these swellings may appear. Some may even go unnoticed by a cat owner until it ruptures or other signs appear. Knowing what to watch for and then how to treat a cat abscess is an important part in helping keep a cat happy and healthy.

What is an Abscess?

An abscess is an infected pocket of pus and pus is a thick fluid that is full of bacteria, white blood cells, and other things. They form as a result of the body's response to an infection. Abscesses can be found throughout the body and can swell to be very large or remain small in a cat. Some abscesses will grow to be so large that they can even rupture causing the pus to leak out.

Signs of an Abscess in a Cat

  • Localized swelling
  • Oozing from a swelling
  • Foul smell
  • Bad breath
  • Lack of appetite
  • Lethargy
  • Fever

Abscesses in cats usually appear as a swelling under the skin but they can also go unseen inside the body or in the mouth under the gums. As a skin swelling, abscesses look just like a tumor or lump but may appear more suddenly. If the swelling stretches too much it may cause the skin to tear and start oozing pus. This results in a foul smell from the leaking infected area.

black cat
black cat

If an abscess is inside the mouth, a cat may have especially bad breath, not want to eat, and become lethargic. Abscesses inside the body may also result in lethargy and a decrease in appetite since they are indicative of an infection. Systemic infections cause a cat to feel sick and develop a fever.

Causes of Cat Abscesses

The most common types of abscesses in cats are in the mouth and under the skin but abscesses can pop up almost anywhere in or on a cat. Abscesses are usually described by where they appear in the body and are caused by various bacteria including E. coli, certain Streptococcus species, Pseudomonas, Mycoplasma, Pasteurella multocida, Corynebacterium, Actinomyces, Nocardia, Bartonella, Bacteroides, Clostridium, and Fusobacterium.

  • Dental abscesses: Characterized by being inside the mouth, dental abscesses are found around diseased teeth. When bacteria builds up on the surface of a tooth, the gums become inflamed which leads to gingivitis. If this bacteria doesn't get removed from tooth brushing or a professional dental cleaning, it continues to stick to the tooth, gathers saliva and food debris, and forms plaque and calculus. This can cause abscesses under the gumline. If that bacteria also gets into the root canal of a broken or diseased tooth, such as one with a resorptive lesion, it can cause a tooth root abscess. Dental abscesses are common in cats but may be difficult for the average cat owner to notice.
  • Bite wound abscesses: In order for a cat to develop a bite wound abscess it needs to be bitten by another animal. This is why bite wound abscesses are most common in cats that spend time outdoors. When a cat gets bit, bacteria enters the wound and an abscess begins to form. These are seen under the skin of cats as lumps and usually aren't noticed by the cat owner until they rupture and begin to ooze pus. Theses abscesses may feel hot to the touch as well as cause skin inflammation.
  • Internal abscesses: Unable to be seen from the outside of a cat's body, internal abscesses occur on the internal organs from inflammation, disease, and foreign objects. These are far less common than bite wound and dental abscesses in cats but still occur.
short-fur brown and black cat close-up photography
short-fur brown and black cat close-up photography

Diagnosing Cat Abscesses

If a veterinarian suspects a skin abscess from a bite wound or other injury on a cat they may stick a needle with a syringe attached into it in order to see what is inside. If it is an abscess, pus will be will be drained out but if it is a tumor it will not. These types of abscesses are typically very easy to diagnose without much testing.

If a dental abscess is suspected, a veterinarian will examine a cat's mouth for evidence of pus but anesthesia and X-rays will need to be performed to thoroughly inspect the mouth. Abscesses will show up on X-rays and dental probes will be used to examine the teeth.

If an internal abscess is suspected, ultrasound may aid a veterinarian in diagnosing it but visualization of the pus filled pocket may need to be done in the operating room. Surgery is typically needed to find internal abscesses.

tuxedo cat sitting on white floor
tuxedo cat sitting on white floor
shallow focus photo of orange kittne
shallow focus photo of orange kittne

Sometimes bacterial cultures will be performed in order to diagnose the specific type of bacteria causing the abscess. This will aid the veterinarian in treating the abscess.

Treatment of Cat Abscesses

Antibiotics and other medications will be used to treat the abscess. Tooth extractions may be necessary for tooth root abscesses along with a thorough teeth cleaning. Surgery may be necessary to lance skin abscesses to allow the infection to drain or to remove the abscess if it is internal.

How to Prevent Cat Abscesses

Regular dental care is key to helping prevent dental abscesses from forming. Some cats have more problems than others with dental disease but keeping their teeth clean can help prevent abscesses.

Keeping cats indoors will help prevent bite wound abscesses. This isn't always possible of course but a cat can't get a bite wound without another animal being around so it is the best way to prevent them.