5 Common Causes of a Swollen Ear in Cats

Cats often get swollen ears that are painful and uncomfortable. It is not uncommon to see a cat with one or both ears red and swollen. However, it is more likely that one ear will swell, as opposed to two.

Swollen ears in cats occur when the blood vessels in a cat’s ear flap bursts. It stings and causes the cat to try and scratch their ears, only making it worse. There are many ways to treat the symptoms, however, you need to figure out the underlying cause first.

cat swollen ear

What Causes a Cat’s Ear to Swell?

There is a long list of things that cause swollen ears in cats. Listed below are some of the main causes.

Yeast, Bacterial, or Mite Infection

One of the most common causes of swollen ears in cats are ear infections; these ear infections can be classified as bacterial infections (either cocci or rods), yeast, ear mites, or even a combination of all three.


The most common cause of ear infections is from ear mites, which are a type of parasite that live on the outside of the ears. These tiny bugs are only a 1/8th inch long and found naturally on dogs and cats. However, the problem occurs when there is an overabundance on a pet, it can cause a buildup of debris in the ear. This debris can have black discharge, cause scratching, and/or head shaking. Ear mite infections often occur in kittens and can lead to a secondary yeast or bacterial infection.  While ear mites are very contagious and can be spread between cats, they are not contagious to humans.  

Mites are found on cats and dogs naturally. However, when there are too many that reproduce, they start to latch on and cause rashes, lesions, and marks. Mites travel throughout a cat’s body and jump from one host to another. If your cat has mites, the little bugs probably are harboring into your cat’s skin by their ears.

Swollen ears occur because of mite infections that don’t get resolved. Cats that have chronic mite infections can develop swollen ears as the bugs bite and harm your cat’s inner and outer ear.

Bacteria/ Yeast

Another type of infection but less common in cats can occur from either bacteria or yeast. Bacteria comes in two types, rods and cocci. Cocci is naturally occurring in ears but at a low rate, when there is an overabundance of cocci it can lead to an infection. Rods, however, are not a common bacteria found in the ear canal and is harder to treat. Yeast is also a common organism found on the skin and ears, but thrive in a moist environment. Yeast overgrowth can occur with underlying allergies, recent bathing, or if another pet in the household grooms their ears.  

It is important to schedule an appointment with your veterinarian if any of these signs occur. While some ear infections can be acute (quick onset, short acting), there may be other underlying issues that must be addressed to ensure that the ear infections do not reoccur.

Skin Allergies

Another chronic skin condition present in cats with swollen ears are skin allergies. Cats typically don’t have any severe allergies, but they can react to allergens like dust, dirt, or mold, to name a few. Skin allergies produce rashes, scabs, painful bite marks, and infections. If your dog continues to scratch themselves, the open wounds can lead to infections where pus fills underneath the skin.

Since skin allergies mainly affect sensitive spots like a cat’s ear, their ears can swell up with all the irritation and scratching.

Trauma to the Ears or Skull

Anything that can make the blood vessels burst in a cat’s flap, can lead to a swollen ear. If your cat has fallen and hurt their ear, it may develop swelling overtime. This is one of the least concerning health conditions because the underlying condition is explainable.

However, you should take your cat to the veterinarian to check for any trauma if they fall. Even if your cat does not display the symptoms of having swollen ears, it is good to double check. Your cat can suffer from trauma when falling or getting hit by a blunt and heavy object.

How Cats are Diagnosed with Swollen Ears 

When you take your cat to the vet for a swollen ear, they will start by taking a physical exam. The vet will ask the pet owner questions about the symptoms and for how long they have been displaying these symptoms.

After the general questions, to diagnose your cat with swollen ears, the vet will need to take a closer look at your cat’s ear with a flashlight. The light helps the veterinarian see your cat’s ear clearly. Sometimes, with swollen ears, fluid will build up which causes the swelling. The inflammation cannot go down without a special procedure.

There are no tests that your vet can conduct on your cat to state if your cat has a swollen ear or not. The diagnosis is based on the symptoms, severity, history, and your vet’s experience. Since this condition is not serious or life-threatening, it does not take long to diagnose or treat.

Treatment Options

To treat swollen ears in cats, you need to get medical attention from a veterinarian. If the swelling does not go away alone without medical intervention, your cat’s vet will drain their ears of fluid. As the fluid leaves, your cat should feel relief.

Since this condition is chronic, you will likely have to bring your cat multiple times to get their ears drained as it swells again. Thankfully, you can prevent and manage the symptoms of swollen ears at home.

Preventing Your Cat’s Ears from Swelling

It should be easy to prevent swollen ears in cats since you have control over their grooming and playdates. Since mites and ear infections are very contagious, you should separate and postpone kitten play dates until everyone is mite free.

This not only prevents further infections, but also prevents the cat from spreading the mites. Another way to prevent swollen ears in cats is to keep your cat’s coat and skin dry and clean. This is not something pet owners usually worry about since their cat’s groom themselves and do not react well to water.

Call Warrick Veterinary Clinic

In conclusion, there are 5 common causes of a swollen ear in cats. Although it may look scary and concerning, a swollen ear typically has an explanation and can be treated quickly. You can also prevent your cat from developing a swollen ear by limiting playdates with other cats and seeking quick treatment for skin and ear infections. Need to talk with a veterinarian about your cat’s swollen ear? Call (812) 897-4855 or use the online form to book an appointment at Warrick Veterinary Clinic.