Dog Ear Infections: Symptoms, Causes & Treatment

Not a substitute for professional veterinary advice. Ear infections don’t resolve on their own — if you spot the signs below, book a vet visit.

If your dog keeps shaking their head, scratching at their ears, or you’ve noticed a sour smell coming from one side of their head, there’s a good chance you’re dealing with an ear infection. It’s one of the most common reasons dogs end up at the vet — by some estimates, up to one in five dogs will deal with one — and while it’s rarely an emergency, it is genuinely painful and won’t clear up without treatment.

Here’s how to recognize one, what actually causes them, and what to expect once you’re at the vet.

Signs of an Ear Infection

Watch for any combination of the following:

Head shaking or tilting
Scratching at one or both ears
A strong or sour odor from the ear
Redness, swelling, or visible discharge (dark, waxy, or pus-like)
Rubbing the side of their face against furniture or the floor
Sensitivity or flinching when the ear is touched
Loss of balance or stumbling (a sign the infection may have reached the inner ear)

Dogs with an outer ear infection often just tilt their head slightly out of discomfort. If the head tilt is paired with stumbling or a loss of coordination, that points to a deeper infection affecting balance — which needs faster attention.

What Causes Dog Ear Infections

Ear infections rarely have just one cause. According to veterinary dermatologist Dr. Ashley Hood, infections typically start when the skin inside the ear becomes irritated or its normal environment changes, which lets bacteria or yeast — organisms that are always present in small, harmless numbers — overgrow. The most common underlying triggers include:

Allergies (environmental or food-related) — by far the most common root cause of recurring infections
Moisture trapped in the ear after swimming or bathing
Ear mites, especially in puppies
Foreign objects, like grass seeds or debris
Anatomy — dogs with floppy ears or narrow ear canals (Cocker Spaniels, Basset Hounds, Labradors) trap moisture more easily and are more prone to infections

Emily Pashaian-Grant, DVM and medical director at VCA Sylvania Vet Animal Hospital, notes that the underlying issue is almost always an “itchy” or unhealthy ear environment that lets germs take hold — which is why treating the infection alone, without addressing the cause, tends to lead to it coming right back.

Outer, Middle, and Inner Ear Infections: Why It Matters

Most ear infections start in the outer ear canal (otitis externa) and are the easiest to treat. But if left alone, an infection can spread inward:

Outer ear (otitis externa): The most common type. Causes redness, odor, discharge, and head shaking.
Middle ear (otitis media): Usually develops from an untreated outer ear infection. Can affect balance and, in some cases, hearing.
Inner ear (otitis interna): The most serious. Can cause a persistent head tilt, loss of balance, abnormal eye movements, and in advanced cases, facial nerve issues on the affected side. This level of infection sometimes requires hospitalization and IV fluids if your dog becomes too disoriented or nauseated to eat or drink.

This is the main reason vets discourage “waiting it out” — an infection that’s mildly annoying in week one can become a much bigger problem by week three.

Scenario Guide

My dog keeps shaking their head and scratching one ear

This is the classic early sign. Book a regular (non-emergency) vet appointment. Don’t clean the ear yourself with random home remedies first — if the eardrum is compromised, some solutions can cause further damage, and your vet will want to see the ear in its current state to diagnose it accurately.

My dog’s ear smells bad and there’s dark discharge

A dark, coffee-ground-like discharge often points to yeast or ear mites, while other colors and textures can indicate bacterial infection. Either way, this needs an actual diagnosis — a vet will look at a sample under a microscope (ear cytology) to determine exactly what they’re dealing with before prescribing treatment, since yeast and bacterial infections are treated differently.

My dog has a head tilt and seems off-balance

Treat this as more urgent. A head tilt combined with stumbling suggests the infection has reached the middle or inner ear, which affects the structures responsible for balance. Call your vet promptly rather than waiting to see if it improves.

My dog gets ear infections over and over again

Recurring infections are a sign the underlying cause — usually allergies — hasn’t been addressed. Ask your vet about allergy testing. Managing the root cause is the only way to break the cycle; repeatedly treating the infection itself without addressing why it keeps happening tends to just delay the next flare-up.

What to Expect at the Vet

Your vet will start with a history (how long symptoms have been present, whether this has happened before, any known allergies) and an otoscopic exam — using a lighted instrument to look into the ear canal and check the eardrum. They’ll usually also take a cytology sample to identify whether they’re dealing with bacteria, yeast, mites, or a combination.

Treatment is typically a topical medication applied directly into the ear, sometimes combined with an oral antibiotic, antifungal, or anti-inflammatory for more severe cases. Some newer treatments (like Claro or Osurnia) are long-acting and applied once at the clinic; others are sent home for you to administer over 1–2 weeks. Most uncomplicated infections clear up within that window — chronic or severe cases can take considerably longer and may need a recheck to confirm the infection has fully resolved before stopping treatment early.

Can You Treat a Dog Ear Infection at Home?

Not effectively, and this is worth being direct about: there’s no reliable home remedy that resolves an actual infection. Over-the-counter cleansers can help with mild irritation or as a preventive step, but if your dog is already showing signs of infection, home treatment without a diagnosis risks masking symptoms while the underlying problem gets worse — or, if the eardrum is affected, actively causing harm with the wrong solution.

What you can do at home is routine ear cleaning as prevention (more below) — that’s a different thing from treating an active infection.

Preventing Future Ear Infections

Clean regularly, not reactively. For dogs prone to ear issues (floppy ears, frequent swimmers, known allergy sufferers), a vet-approved ear cleanser once a month helps keep the canal dry and balanced.
Dry ears thoroughly after baths or swimming. Trapped moisture is one of the most common and preventable triggers.
Manage allergies. If your dog has a known food or environmental allergy, staying on top of it will do more to prevent recurring ear infections than any cleaning routine alone.
Don’t over-clean. Ironically, cleaning too aggressively or too often can irritate the ear canal and increase infection risk — ask your vet what frequency makes sense for your specific dog.

FAQ

How do I know if it’s an ear infection or just dirty ears? Dirty ears usually just have some wax buildup with no smell, redness, or scratching. If there’s odor, discomfort, or your dog is shaking their head, it’s worth a vet check rather than guessing.

Are ear infections contagious to other pets? Ear mites are contagious between pets; bacterial and yeast infections generally aren’t. Your vet can tell you which you’re dealing with.

How long does a dog ear infection take to heal? Most uncomplicated infections clear up in 1–2 weeks with proper treatment. Severe, chronic, or untreated infections can take months and may require a change in medication or, rarely, surgery.

Can I use human ear drops on my dog? No — always use a product your vet has prescribed or approved. Human formulations aren’t dosed or designed for a dog’s ear canal and pH.

Sources referenced for accuracy: American Kennel Club’s veterinary guide to dog ear infections (featuring Dr. Ashley Hood); Daily Paws’ interview with Emily Pashaian-Grant, DVM (VCA Sylvania Vet Animal Hospital); PetMD’s clinical overview by Dr. Amanda Simonson; Merck Veterinary Manual’s otitis externa reference; VCA Animal Hospitals’ overview of otitis interna.

Why Is My Dog Shaking? Causes, Warning Signs & When to Call the Vet