Ear Infections in Dogs: Signs, Causes and Care

At a glance

What it is	Inflammation and infection of the ear canal, usually the outer part between the ear flap and the eardrum
Who's at risk	Any dog, but especially those with allergies, floppy or hairy ears, narrow ear canals, or who swim often
Main signs	Head shaking, scratching, a bad smell, redness, discharge and pain when the ear is touched
Contagious?	Bacterial and yeast infections are not usually passed between dogs; ear mites can spread to other pets
Can it be prevented?	Often reduced by managing allergies, drying ears after swimming and regular checks, but not always prevented

What it is

A dog's ear canal is longer than ours and shaped a little like the letter L. It runs down the side of the head and then turns inwards towards the eardrum. That shape is good at protecting the inner ear, but it also means that warmth, moisture and debris can become trapped deep inside.

An outer ear infection, which vets call otitis externa, happens when the skin lining that canal becomes inflamed. Inflamed skin produces more wax and grease, the canal can swell and narrow, and the yeasts and bacteria that normally live there in small numbers start to multiply. The result is an itchy, sore, often smelly ear.

It is helpful to think of an ear infection as a symptom of something else rather than a problem on its own. Infection is usually the final step. Something first upsets the healthy balance in the ear, and that something is what your vet will want to understand so the problem does not keep returning.

Common underlying causes

• Allergies. This is one of the most frequent causes. Dogs with food allergies or environmental allergies, such as to pollen or house dust mites, often have itchy, inflamed ears, sometimes alongside itchy paws, skin or tummy.
• Ear shape and hair. Long, heavy ear flaps, lots of hair in the canal or naturally narrow canals reduce airflow and hold in moisture.
• Moisture. Swimming, bathing or wet weather can leave water in the canal, creating a warm, damp environment where yeast and bacteria thrive.
• Foreign bodies. Grass seeds are a well-known culprit in summer. Their arrow shape lets them travel down the canal but not back out, and they can cause sudden, intense discomfort in one ear.
• Ear mites. These tiny parasites are more common in puppies and in households with cats. They cause intense itching and a dark, crumbly discharge.
• Other factors. Hormonal conditions, growths in the canal and skin conditions can also play a part, particularly in dogs whose ear problems keep coming back.

Signs to watch for

Ear infections can affect one ear or both. You might notice:

• Shaking the head more than usual, or holding one ear slightly lower
• Scratching or pawing at the ear, or rubbing the head along furniture or the floor
• An unpleasant or yeasty smell from the ear
• Redness or swelling inside the ear flap or at the entrance to the canal
• Discharge, which may be brown, yellow, black or bloody, and waxy or runny
• Pain or flinching when the ear or head is touched, or reluctance to be stroked there
• Crusting or hair loss around the ear from scratching
• A swollen, soft, puffy ear flap, which can be a blood blister caused by vigorous head shaking

Some dogs become quieter or grumpier than usual when their ears hurt. Changes in mood can be a clue, particularly in dogs who do not scratch much.

If you are unsure what your dog's signs might mean, our symptom checker can help you think through them and decide how soon to seek help. You can also read more in our guide to why dogs shake their heads.

When to see a vet

Book an appointment with your vet if you notice any of the signs above, especially smell, discharge or pain. Ear infections rarely clear up on their own, and the longer they go on, the more the canal can thicken and narrow, which makes future treatment harder.

Try to see your vet the same day if:

• Your dog suddenly starts shaking their head violently or holding it to one side after a walk through long grass, as a grass seed may be lodged in the ear
• The ear is very painful and your dog will not let you near it
• The ear flap has become swollen and puffy

Treat it as urgent and contact your vet straight away if your dog has:

• A sudden head tilt
• Loss of balance, stumbling, circling or falling over
• Unusual flicking movements of the eyes
• Facial drooping on one side

These signs can mean the middle or inner ear is involved, or point to another problem affecting balance, and they need prompt attention.

How vets diagnose it

Your vet will usually start by asking about your dog's history, including whether this has happened before, whether your dog swims, and whether there are signs of itchiness elsewhere on the body.

They will then look inside the ear with an otoscope, an instrument with a light and a cone that lets them see down the canal. This helps them check for redness, swelling, discharge, grass seeds, mites and growths, and see whether the eardrum looks intact. That last point matters, because some ear medications and cleaners should not be used if the eardrum is damaged.

Your vet may take a swab of the discharge and look at it under a microscope. This quick test, called cytology, shows whether yeast, bacteria or both are present, and helps them choose the most suitable treatment. For infections that are severe or keep coming back, they may send a sample to a laboratory to identify the bacteria and which treatments are likely to work.

If the ear is very sore, swollen or full of debris, your dog may need sedation or a general anaesthetic so the vet can examine the canal properly and clean it out safely. For recurrent problems, your vet may also suggest investigating allergies or other underlying conditions.

Treatment and management

Treatment is always prescribed by your vet, based on what they see in the ear and on the swab. It often involves medicated ear drops and sometimes a cleaning solution. Some dogs also need tablets, for example to reduce pain and inflammation or to treat a deeper infection.

A few things make a big difference to how well treatment works:

• Finish the whole course. Ears often look and feel better within a few days, but the infection may not be fully cleared. Stopping early can allow it to come back and can make it harder to treat.
• Follow instructions closely. Your vet will tell you how much to use, how often and for how long. Ask them to show you how to apply drops so the medicine reaches the canal rather than just the ear flap.
• Go to recheck appointments. Your vet may want to look in the ear again, and sometimes repeat the swab, to confirm the infection has gone before stopping treatment.
• Address the cause. If allergies, ear shape or swimming are playing a part, managing those is key to preventing repeat infections.

Cleaning your dog's ears

Only clean your dog's ears if your vet recommends it, and in the way they show you. Cleaning a sore ear the wrong way can hurt, push debris deeper or irritate the canal further. Your vet can recommend a suitable cleaner and how often to use it.

Never push cotton buds down into your dog's ear canal. It is easy to pack wax and debris further in or damage the delicate lining. If your vet advises cleaning, you will usually be shown how to fill the canal with cleaner, massage gently at the base of the ear and then wipe away only what comes up to the entrance, using cotton wool.

Ears that have been infected for a long time can become permanently thickened and narrowed. In a small number of these cases, surgery may be discussed. This is uncommon, and catching infections early is the best way to avoid reaching that point.

Prevention

Not every ear infection can be prevented, but you can lower the chances:

• Check your dog's ears regularly. A quick look and sniff once a week helps you get to know what normal looks like for your dog, so you notice changes early.
• Dry ears after swimming or bathing. Gently dry the ear flap and the entrance to the canal with a soft towel. If your dog swims often, ask your vet whether a drying ear cleaner would help.
• Check after walks in long grass. In late spring and summer, look over your dog's ears, paws and coat for grass seeds, particularly if they have long or feathered ears.
• Manage allergies. If your dog has allergies, working with your vet to keep them under control is one of the most effective ways to reduce ear problems.
• Keep up with parasite control. Ask your vet whether your dog's parasite treatment also covers ear mites, especially if you have cats.
• Do not over-clean. Healthy ears usually look after themselves. Frequent cleaning when it is not needed can upset the natural balance.

Living with it

For many dogs, an ear infection is a one-off that clears with a single course of treatment. For others, especially those with allergies or certain ear shapes, ears can be an ongoing area to keep an eye on.

If your dog is prone to ear problems, it helps to build ear checks into your routine, keep a note of flare-ups and possible triggers, and see your vet early rather than waiting. Many owners find that with good allergy management and a regular, vet-guided care plan, their dog's ears stay comfortable for much longer between episodes.

Handling your dog's ears gently during calm, happy moments, with a treat or praise, can also make examinations and treatment much less stressful for both of you.