Cat Abscess – Causes, Symptoms and Treatment

What is an abscess?   How does an abscess occur?   What are the symptoms of an abscess?   How is an abscess diagnosed?   What is the treatment for an abscess?   Preventing an abscess

Bite wound abscesses in cats at a glance

  • An abscess is a pocket of pus which occur most often when bacteria are injected under the skin, via a puncture wound. Hence the name ‘bite wound abscess’.
  • Symptoms include a firm, painful lump, fever, lethargy and loss of appetite. If the abscess has ruptured, there will be a foul-smelling discharge from the affected area.
  • Treatment includes surgery to open the abscess if it has not ruptured, followed by flushing the wound with antiseptic and antibiotics.

Abscess in cats

Image courtesy Nottingham Vet School, Flickr

What is an abscess?

An abscess is a localised pocket of pus which is surrounded by a protective pyogenic membrane. Bacteria usually reside on the skin without causing any harm, however, if a break allows entry of this bacteria beneath the skin surface, most often when bacteria are injected under the skin, via a puncture wound.

An inflammatory response occurs, drawing huge amounts of white blood cells to the area and increasing regional blood flow. Pus forms, which is an accumulation of fluid, toxins, living and dead white blood cells, dead tissue and bacteria. The abscess is surrounded by a thin membrane known as a pyogenic membrane, which  This area begins to grow, creating tension under the skin and further inflammation of the surrounding tissues. As the abscess grows, the skin thins and weakens, eventually causing the abscess to rupture and the pus drains out.

An abscess can form in any part of the body including under the skin, in the mouth (dental abscess) and in organs such as the liver and pancreas. This article relates to abscesses under the skin. The most common bacteria involved are staphylococci and streptococci.

How does an abscess occur?

Most abscesses are caused by a puncture wound which introduces bacteria under the skin. The skin is remarkable in its ability to heal quickly, so the overlying skin heals from the puncture wound, the introduced bacteria remain trapped underneath the skin in a warm, moist environment.

The most common cause of a penetrating puncture leading to an abscess is from a cat bite, the oral cavity, including the teeth, harbour a great number of bacteria which are injected into the skin during penetration. Abscesses are seen more often in un-neutered male cats who are allowed to free roam as they are more territorial and therefore become involved in cat fights with neighbourhood cats. There is an increase in cats presenting with abscesses in spring as this is cat mating season.

Other causes of abscesses include scratches and any penetrating object such as a thorn, splinter, grass seed or glass shard.

Abscess symptoms:

Abscesses are most frequently found around the head, neck, limbs and back and base of the tail, not all cats will display symptoms.

By the time you find the abscess, the skin may be sufficiently thin resulting in the abscess draining (this is known as ‘pointing‘ and usually occurs when the abscess is close to the skin). If it has drained you may notice a thick, yellow and foul smelling discharge and a hole in the skin (see image). If the abscess is located deeper under the skin, you may notice an indentation (or a ‘pit‘) when pressure is applied to the area of swelling.

Other common symptoms of an abscess can include:

  • Hot, swollen and painful area, which may be red and/or with missing fur
  • Fever
  • Loss of appetite
  • Lethargy – Sleeping more, reluctance to play or go outside
  • Lameness – Limping and reluctance to bear weight on affected limb
  • Listlessness – Can’t seem to settle, loss of interest in activities he usually enjoys
  • Hunched over appearance
  • If the abscess bursts, you may notice oozing and a foul-smelling odour from the affected area

An abscess isn’t always visible, especially as the coat may hide the wound, so if your cat is acting off colour, appears to be in pain or displays any other symptoms above, it is advisable to seek veterinary advice.

Diagnosing an abscess:

Abscess in cats

Image monkeymark, Flickr

Most abscesses can be diagnosed during a physical examination.

Your veterinarian may take a sample of the discharge and culture it to determine the bacteria involved so that he can prescribe the best antibiotic for that particular bacteria.

He may also recommend a FeLV (feline leukemia) and FIV (feline AIDS) blood test to rule out infection which is more common in outdoor entire cats who fight.

Treating a bite wound abscess in cats

Abscess in cats

Image courtesy Duncan Creamer, Flickr

  • If the abscess hasn’t drained, your veterinarian will clip the fur surrounding the abscess, lance it, drain the pus, remove any necrotic tissue flushed with antiseptic and/or antibiotic solution. This will either be done under heavy sedation or general anaesthetic, your cat may need to stay in hospital for a day or two while he recovers.
  • If the abscess has drained, your veterinarian will flush the wound with antiseptic and/or antibiotics.
  • If the abscess is large, a surgical drain (see image) may be required to assist with the removal of pus. A drain is a thin plastic tube which is inserted under the skin which will allow any pus to drain out. The drain will need to be flushed daily with antiseptics.
  • Your veterinarian will either administer a long-acting antibiotic via injection or prescribe a course of oral antibiotics.
  • A warm compress applied several times a day can be beneficial to increase blood flow to the area which can hasten healing.


  • Follow your veterinarian’s instructions carefully and administer any antibiotics as prescribed.
  • Your cat may be required to wear an Elizabethan collar, especially if he has a drain, this will prevent him from pulling it out.
  • Keep your cat indoors while he heals.
  • Watch for signs of infection including redness, oozing, and swelling of the affected area.
  • Follow up with your veterinarian if required.

How to avoid an abscess in cats

The best way to avoid abscesses in cats is to spay and neuter cats and prevent them from free roaming.

Check your cat for bites, scratches, and wounds if he has been involved in a cat fight, any wounds should be cleaned with antiseptic (see here for a list of antiseptics safe to use on cats).

See your veterinarian if you notice any lumps, signs of pain or fever.  We do not recommend treating an abscess at home, an abscess can rupture into the bloodstream causing septicemia (bacteria in the blood), which is often fatal.

While this won’t prevent an abscess, keep your cat’s vaccinations up to date, this is particularly important if your cat is free roaming.

It should be noted that people can develop abscesses too and it is not uncommon for veterinarians and vet nurses to develop them as a result of a scared or angry cat biting them. This is why it is extremely important for pet owners to be careful around sick, injured and agitated cats, even the most placid cat can lash out if he is scared or in pain. If you are bitten or scratched by a cat, clean the wound immediately and as has been recommended above, keep a careful watch for signs of an abscess. If you do think you have one, seek medical attention immediately.

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