Swollen Ear: Cat

Isolated cat


  • If your cat has developed a big, swollen earflap, it’s most likely to be due to a condition called an aural haematoma (burst blood vessel inside the flap).
  • There are other causes of swollen ears (see below).
  • Contact your vet if you notice your cat has something wrong with their ears – ear problems are very uncomfortable.
  • Never attempt to treat a swollen ear at home.

Aural haematoma

An earflap that suddenly balloons in size, becomes hot, painful and heavy is likely to be caused by an aural haematoma (a burst blood vessel inside the earflap). It is possible (but quite rare) for haematomas to develop in both ears at the same time. Aural haematomas are usually because of an underlying ear problem such as an ear infection or ear mites.

Cat with swollen ear flap

This cat has a very large aural haematoma filling the whole of his right earflap

Other causes of swollen ears in cats


An injury to an ear may cause a mild swelling – you may also see a wound, hair loss or bruising.

Allergic skin disease

If your cat’s ears are red, thickened and itchy, this could be an allergic skin reaction, which should be checked by your vet.

Sudden allergic reaction

If both your cat’s ears become suddenly very swollen, red and puffy, they have swellings elsewhere (e.g. face, eyes, nose, feet) or are having difficulty standing up this could be a sudden, severe allergic reaction to something (anaphylaxis). If you think this is the case, call your vet immediately.

Ear infection

Ear infections don’t often cause swollen earflaps, they tend to cause a swelling inside the ear canal alongside pain, a smell and itchy ears.

Treating a swollen ear at home

Never try to treat a swollen ear at home, there are many possible causes that your vet will need to rule out. Your vet will examine your cat and use an otoscope to find out what is wrong with their ear.

Leaving an ear problem without treatment is likely to cause serious problems in the future. Attempting to treat an ear problem at home could result in severe infection, injury and pain.

When to contact your vet

Contact your vet if you notice your cat has a swollen earflap. Your vet will find out what has caused it and provide treatment.

Never attempt to treat a swollen earflap at home.

Consider insuring your cat as soon as you get them, before any signs of illness start. This will ensure you have all the support you need to care for them.

Published: June 2019

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Written by vets and vet nurses. This advice is for UK pets only.

Illustrations by Samantha Elmhurst