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What Causes a Dog’s Ear to Swell? 6 Vet-Verified Reasons

Written by: Elizabeth Gray

Last Updated on March 28, 2024 by Dogster Team

Dog ears with broken capillaries Ear swelling and illness due to scratching caused by fungus or yeast

What Causes a Dog’s Ear to Swell? 6 Vet-Verified Reasons


Dr. Ashley Darby Photo


Dr. Ashley Darby

BVSc (Veterinarian)

The information is current and up-to-date in accordance with the latest veterinarian research.

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If you notice your dog holding their head strangely or digging a paw into the side of their face, it could be because their ears are bothering them. When you investigate, you may find that your dog’s ears are swollen, among other signs. But what could be causing this uncomfortable condition? Here are six possible reasons that can cause your dog’s ear to swell.

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The 6 Causes of Dog Ear Swelling

1. Ear Hematoma

If the flap of your dog’s ear (pinnae) is swollen, they could be suffering from an ear hematoma. Hematomas occur when a blood vessel bursts in the dog’s ear, usually because the pup has been shaking their head excessively.

The blood fills the space between the skin and cartilage, essentially forming a fluid blister. Fixing an ear hematoma involves correcting the problem and treating the underlying reason the dog was shaking their head in the first place. See your veterinarian if you suspect your dog has an ear hematoma.

Vet showing the dry ear skin on dog suggesting symptom of Aural Hematoma
Image Credit: ThamKC, Shutterstock

2. Ear Infection

Ear infections can also cause your dog’s ear to swell due to inflammation. The ear canal or ear flap can swell if your dog suffers from an infection. Ear infections are generally caused by yeast or bacteria. Dogs with floppy ears or narrow ear canals are more prone to ear infections. They’re also common among dogs who spend a lot of time in the water. Besides ear swelling, you may notice discharge, redness, a foul odor, and your dog shaking their head or scratching frequently.

3. Allergies

Chronic allergies or an allergic reaction could cause your dog’s ears to swell. Dogs with food or seasonal allergies live with so much itching in their bodies that it may lead to secondary issues like ear infections.

Bee stings or insect bites can lead to an allergic reaction that causes your dog’s ears to swell. Like humans, dogs can suffer severe allergic reactions or anaphylaxis. It’s best to take your dog to a veterinarian if you suspect an allergic reaction; their vitals will be checked and treatment may include an antihistamine or fluids.

Brown dog scratches itself
Image Credit:, Shutterstock

4. Foreign Body

If your dog gets foreign material stuck in their ear, it could cause swelling and pain. You may notice your dog constantly holding their head to the side, shaking their head, or pawing at their ears if they have a foreign body stuck inside. Your vet will need to investigate your dog’s ears and possibly perform more specialized tests to determine if foreign material is present.

5. Ear Mites

Ear mites are microscopic parasites that feed on the wax in your pup’s ears. They’re more common in cats but can occur in dogs, too. Ear mite infestations can cause discharge and swelling in your dog’s ears.

You may also notice hair loss from your dog scratching their itchy ears. They can get ear mites from contact with another infected pet. Ear mite infections are diagnosed by looking at a swab of the discharge under a microscope.

dog's ear affected by an ear mite
Image Credit: Glikiri, Shutterstock

6. Mass

Your dog’s ear could swell due to a mass growing on or inside of it. Masses can grow slowly or quickly. Not every mass is cancerous, either, and cancers can be benign or malignant. As part of your dog’s regular grooming routine, you should be performing a quick check for any new growths or swelling, including in their ears.

The earlier you can catch any masses, the faster they can be removed. Your vet may take a sample of the ear mass to determine whether it’s cancer before suggesting a treatment plan.

What to Do If Your Dog’s Ear Is Swollen

As you can see, there are multiple possible causes of ear swelling in dogs, and you’ll need to see a veterinarian to diagnose the issue properly. Although ear swelling is generally not an emergency, many ear conditions can be painful for your dog.

In addition, if the ear swelling is the result of an allergic reaction, more serious signs could present themselves. Left untreated, external ear infections can result in middle or inner ear infections.

Your veterinarian will examine your dog’s ears and take samples to examine under a microscope. If your dog has an ear hematoma, a minor surgical procedure may be necessary to correct the problem. Other causes of ear swelling may be treated by cleaning and medications.

It’s essential to follow all your vet’s instructions as you deal with the cause of your dog’s ear swelling.

male veterinarian checking up dog in vet clinic
Image Credit: SeventyFour, Shutterstock

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Ear swelling and other ear issues are some of the most common medical problems dogs experience. While they typically aren’t life-threatening, ear issues can make your dog miserable and you miserable, too. If your dog constantly suffers from ear problems, you can talk to your veterinarian about a possible referral to a veterinary dermatologist for help.

Featured Image Credit: Kittina05, Shutterstock

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