Dog Ear Infection: Signs, Causes & Treatment (2026)

What an ear infection actually is

"Ear infection" almost always means otitis externa — inflammation and infection of the external ear canal, the L-shaped tube leading down to the eardrum. A dog's ear canal is deeper and more vertical than ours, which traps moisture and debris and makes it a comfortable spot for yeast and bacteria to overgrow. A few of these organisms live on healthy skin normally; trouble starts when something tips the balance and they multiply. Left alone, an outer-ear infection can work its way deeper into the middle and inner ear, which is harder to treat, so early attention matters.

Signs to watch for

Signs can come on fast or build up slowly, and one or both ears may be affected. Common ones include:

• Head shaking or tilting the head to one side
• Scratching or pawing at the ear, or rubbing the ear along furniture and the floor
• A foul or unusual odor — yeast tends to smell sweet or musty, bacteria more putrid
• Discharge in the ear: yellow, brown, or bloody
• Redness, swelling, or warmth of the ear flap and canal
• Pain when the ear is touched, or holding the ear down

A little brown wax now and then is normal. What's not normal is a smell you can notice from across the room, a canal that looks angry-red, or a dog that yelps when you touch the ear — those point to infection rather than routine dirt.

What causes it (the part owners miss)

Here's the thing most people don't realize: the yeast or bacteria are often the result, not the root cause. A vet's job is to find what let them overgrow, because if that's not addressed, the infection keeps coming back. The usual underlying drivers are allergies (environmental or food — allergy is involved in a large share of chronic ear cases, and ear infections show up in the majority of dogs with food allergies), trapped moisture after swimming or baths, ear mites, a foreign object like a grass seed lodged in the canal, or excess hair and wax. Ear shape matters too — breeds with long floppy ears or narrow canals, like Cocker Spaniels, Basset Hounds, Golden and Labrador Retrievers, and Shih Tzus, get less airflow and are more prone.

Common root causes

When to see a vet

Ear infections rarely clear up on their own, and the safest move is to book a vet visit soon after you notice the signs rather than waiting it out. Go promptly — and treat it as urgent — if your dog is in obvious pain, the ear is very swollen or bleeding, there's a strong discharge, you see a head tilt with loss of balance or unusual eye movements, or there are signs of hearing loss. Those can signal a deeper middle- or inner-ear problem. Repeated infections in the same ear also deserve a proper work-up to find the underlying cause, not just another round of drops.

Why home cleaning can backfire

It's tempting to grab cotton swabs or a bottle of vinegar and DIY it, but this is where owners often make things worse. Never push cotton swabs down into the canal — you can pack debris deeper or damage the eardrum. And don't pour in vinegar, hydrogen peroxide, or home solutions if the ear is very painful, swollen, bleeding, or if you don't know whether the eardrum is intact: an acidic or harsh liquid reaching a ruptured eardrum causes severe pain and can damage the middle ear. A vet examines the canal with an otoscope and checks the eardrum before choosing a cleaner or medication for exactly this reason. Save the home cleaning for gentle, vet-approved maintenance on a healthy ear.

What treatment looks like

A typical visit starts with an otoscope exam and ear cytology — swabbing the ear and looking at the sample under a microscope to see whether it's yeast, bacteria, or both, which determines the medication. The vet usually cleans the canal, then sends you home with a topical antibiotic and/or antifungal, sometimes with an anti-inflammatory for comfort. Most uncomplicated infections improve within a week or two, but a recheck to confirm the infection has fully cleared is important — stopping early is a common reason it bounces back. Bacterial and yeast cases often need repeated checkups over about 2–4 weeks; stubborn or chronic ears can take months, and a small number of dogs need lifelong management.

Typical US cost ranges

• Exam + ear cleaning + medication (straightforward otitis externa): USD 100–175
• With cytology and recheck factored in: USD 150–500 total
• Antibiotic or antifungal drops on their own: roughly USD 30–50
• Chronic, end-stage ears needing TECA surgery: a few thousand USD (often USD 3,000–4,000+)

Costs swing with your region, the clinic, and how advanced the infection is. Catching it early — while it's a simple outer-ear case — is far cheaper than letting it become chronic, which is where the big surgical numbers come in. Pet insurance may offset some of this, though many policies exclude pre-existing or recurring conditions, so it's worth checking the fine print.

Preventing repeat infections

Prevention is mostly about keeping the canal dry and staying on top of whatever drives the inflammation. Dry your dog's ears gently after swimming and baths, do a quick weekly look-and-sniff so you catch changes early, and use a vet-recommended ear cleaner only as directed — over-cleaning a healthy ear can irritate it just as much as neglect. If your dog gets infections again and again, the real fix is usually managing the underlying allergy with your vet rather than repeating drops. Floppy-eared and swimming dogs need a bit more vigilance.

Track ear health with PetCare AI

Log each ear flare-up, cleaning, and medication course in PetCare AI's care calendar so you can spot a pattern — many owners don't notice their dog gets an ear infection every allergy season until it's written down. Set reminders for recheck visits and finishing the full course of drops, the two lapses that let infections return. You can ask the AI vet assistant to help you sort "normal wax" from "see-a-vet" signs and use the in-app finder to locate a nearby clinic. For any painful, bleeding, or recurring ear, confirm the diagnosis and treatment with your veterinarian — the eardrum needs a real exam before anything goes in the canal.