If you notice small lumps or swellings when stroking or brushing your cat do not be unduly alarmed. There are many possible causes: growths, cancers, infections, allergic reactions to flea bites or foreign bodies such as thorns or airgun pellets. Occasionally your cat may pick up ticks that swell up as they feed on cat’s blood and can easily be mistaken for a skin lump. However, the most likely cause of a lump in your cat is an abscess.
Abscesses are more common in cats than other domestic animals and are usually the result of fighting. Cats have powerful jaws and a variety of unpleasant bacteria live in their mouths that can be injected deep below the skin surface by biting. The bacteria cause an infection that eventually develops into an abscess, a mass of pus walled up inside scar tissue. Cats also use their claws to fight but abscesses caused by scratches are much less common because the wounds are not as deep.
Signs of infection may be present before any swellings develop. Your cat will be listless, go off its food and its nose may become dry. Your cat may resent being handled and a normally docile cat may hiss and scratch when you try to pick it up. If your cat has been bitten on a leg it will probably limp. These signs last for about 3 days before the swelling appears.
Abscesses are most often found on the face, neck and tail although any part of the body can be bitten during a fight. The swellings are painful when touched and the skin surface will feel hot. The swelling often gets bigger for 3-5 days and then may burst, discharging a smelly yellow/green fluid (pus).
It is much more common to see abscesses in tomcats than in neutered male or female cats. Tomcats often fight with one another over territory or sexual favours. However, any cat can be involved in a fight. Shortly after moving house your cat may be more likely to get into fights with resident cats until it has established its own territory.
It is important to take your cat to your vet if you find any sort of lump. It is also worth checking your cat for bite marks if you suspect it has been in a fight. The telltale signs of a fight are a torn or bleeding ear, marks around the eyes and missing lumps of fur. Also look out for limping, lethargy and other signs of infection. If your cat has been bitten there may be a tiny area of matted fur around the bite wounds. Unfortunately wounds are often difficult to spot and the skin surface may heal fast, leaving infection still there beneath the surface.
If you find a bite wound on your cat it should be bathed with a salt solution (1 tablespoon of salt in a pint of water) and the wound watched closely for signs of swelling over the next few days. Sometimes the first indication that your cat has an abscess is when the swelling bursts, releasing foul smelling, creamy white or green pus. If the abscess doesn’t burst naturally your vet will lance it, flush out the remaining pus and then wash it with an antiseptic solution.
Your cat will probably be put on a course of antibiotics lasting between three and seven days. There are many different types of antibiotic that kill different types of bacteria. Your vet will use his experience to select the right antibiotic for the job. If the wound is still infected after a few days tests may be necessary to find which particular bacteria are present and help your vet choose an alternative antibiotic.
Unless your cat is kept permanently indoors there is always a chance of it getting into a fight. But having an intact tomcat neutered will significantly reduce the risk. Cats with certain diseases such as Feline Leukaemia (FeLV) or Feline Immunodeficiency Virus (FIV) have weaker defences against infection and are likely to have more severe problems if they do get bitten. Other diseases can also be spread when cats get together to fight, so always make sure that your cat’s vaccinations are up to date.