Dog Ear Infection: Signs, Causes and Why They Keep Coming Back

Head shaking, scratching at one ear, a sour or yeasty smell, redness, or brown or yellow discharge are the usual signs of a dog ear infection — and it needs a vet who can look inside the canal, not a bottle off a shelf. Ear infections are painful, and the wrong treatment can make them worse.

This page is here so you recognize the problem and understand what the vet visit involves. It does not replace a veterinarian, and self-treating an ear is one of the few home shortcuts that can cause lasting harm.

What you are actually seeing

A head tilt with balance problems is a different order of problem from an itchy ear. Do not wait it out.

Why a vet has to look

Two things have to be established before treatment: what is growing, and whether the eardrum is intact.

The first matters because yeast, bacteria and ear mites need different treatments, and a vet can distinguish them by examining a swab under a microscope. The second matters more. If the eardrum has ruptured — which happens in severe or long-standing infections — some medications reaching the middle ear can cause permanent damage including hearing loss. An otoscope answers that question in a minute.

Medication and dosing are set by your vet based on those findings and your dog's weight. There is no home dosing chart for this, and there should not be one.

The recurrence problem

Some dogs get one ear infection in a lifetime. Others get four a year, and those dogs almost always have an underlying driver.

• Allergies are the most common. An allergic dog's ears are inflamed before anything infects them; the infection is the symptom, not the cause. See why your dog is itching.
• Anatomy. Floppy ears, narrow canals and hairy canals all trap moisture and warmth.
• Moisture. Swimming and baths, especially in a dog who already has one of the above.
• Chronic change. Long-running inflammation thickens and narrows the canal, which makes the next infection more likely and harder to clear.

If your dog is on their third round of drops, the conversation to have is about the driver, not the drops.

What you can and cannot do at home

Routine ear cleaning in a healthy ear — with a proper canine ear cleaner, on your vet's recommendation — is reasonable maintenance, and we cover that technique in the grooming section. An ear that is already painful, smelly or discharging is not a cleaning job.

Things not to do: cotton buds down the canal, which push debris deeper and can damage the drum; anything containing alcohol or vinegar on inflamed skin; leftover medication from another dog or another episode; and human ear drops of any kind.

If your dog will not let you near the ear at all, that is a pain signal worth reporting rather than a training problem to push through. See signs your dog is in pain.

After the appointment

Finish the full course even when the ear looks better on day three — stopping early is a reliable route to recurrence. Go back for the recheck if one is booked, because a vet needs to confirm the canal is genuinely clear rather than quieter.

If the same ear flares again within weeks, ask about investigating the cause properly: allergy management, imaging in stubborn cases, or a referral. That is a more productive spend than a fourth bottle.

A quick triage

Puppies, seniors, and dogs with chronic ear disease

Ear mites are more common in puppies and in dogs recently from a shelter or a litter with several animals, and they cause intense itching with a dark, dry, coffee-ground discharge that looks different from a typical bacterial or yeast infection. A vet distinguishes this on the same swab exam.

A new ear problem in an older dog is usually still infection, but a mass or polyp growing in the canal becomes more likely with age and can look similar from the outside — another reason a vet needs to see inside rather than guess from the smell and the shaking alone.

Dogs with long-standing allergic ear disease can reach a point where the canal itself has thickened and narrowed from repeated inflammation, no longer responding reliably to drops. That is when a vet may raise options beyond medication, up to surgery in the most severe, unresponsive cases — which is exactly why catching the driver early, usually the allergy itself, matters more than treating each flare-up in isolation.

What owners commonly get wrong

Waiting through two or three head-shaking episodes before booking, on the assumption it will settle on its own, is the most common mistake — untreated infections tend to get worse and harder to clear, not better. Reaching for leftover drops from a previous episode is the second: the organism causing this infection may not be the one those drops were prescribed for, and using the wrong medication can delay an accurate diagnosis. The third is treating a persistent smell as normal for the breed; a genuinely healthy ear does not have a strong odor.

What to do next

Photograph the ear, note how long the shaking has been going on and whether it is one ear or both, stop putting anything in it, and book the appointment. If there is a head tilt, loss of balance, or your dog is clearly in pain, make that call today.