Ear Infections in Dogs: Signs, Causes & Treatment
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Ear infections (otitis) are one of the most common reasons dogs see the vet. Signs include head shaking, scratching at the ears, redness, odor, and dark or discharge-filled ears. Most are caused by yeast or bacteria taking hold in an ear that's already irritated — often by allergies or moisture. They need a vet exam and the right ear medication; the underlying cause has to be addressed or they keep coming back.
Signs your dog has an ear infection
Ear infections are itchy and painful, and dogs make it fairly obvious:
- Head shaking and tilting
- Scratching or rubbing the ear against furniture or the floor
- Redness and swelling inside the ear flap and canal
- Odor and dark, waxy or pus-like discharge
- Pain when you touch the ear, or crying when scratching
If your dog is suddenly very painful, has a head tilt, is losing balance, or the ear is severely swollen, see your vet promptly — deeper or middle-ear infections and aural hematomas (a blood-filled ear flap from violent shaking) need timely care.
Why dog ear infections happen
Here's the key insight most owners miss: an ear infection is usually a symptom, not the root problem. Yeast and bacteria live on healthy skin — they only overgrow when the ear environment changes. Common drivers include:
- Allergies (food or environmental) — the number-one cause of recurring ear infections
- Moisture from swimming or baths
- Ear anatomy — floppy ears and hairy or narrow canals (think Cocker Spaniels, Basset Hounds, Poodles) trap warmth and moisture
- Ear mites (more common in puppies), foreign material like grass awns, or excess wax
- Underlying disease such as hypothyroidism
This is why treating only the infection, without finding the trigger, leads to a frustrating cycle of repeats.
How vets diagnose and treat it
Your vet will examine the canal and, crucially, look at a swab of the discharge under the microscope to see what's overgrowing:
| Finding | What it guides |
|---|---|
| Yeast vs. bacteria vs. mites | Which medication will actually work. |
| Eardrum intact or ruptured | Which products are safe to use in the ear. |
| Culture (stubborn cases) | Targeting resistant bacterial infections. |
Treatment usually means a thorough cleaning followed by prescribed ear drops or ointment, sometimes with anti-inflammatories for pain. Follow the full course and return for a recheck — an ear that looks better on the outside can still be infected. Never poke cotton swabs deep into the canal or use leftover or human ear products.
Preventing repeat infections
Prevention centers on keeping ears dry and clean and controlling the trigger:
- Dry the ears after swimming or bathing
- Routine cleaning with a vet-recommended cleaner for ears that build up wax — see how to clean dog ears
- Address allergies with your vet if infections keep returning — this is the real fix for most chronic cases
- Don't over-clean healthy ears, which can cause irritation
Why tracking helps
Ear infections that come back every few months are almost always a clue to an underlying trigger — most often allergies. But that pattern is hard to see in the moment; it only emerges when you look across a year.
Practical take: Logging each episode — which ear, the time of year, and whether it followed a swim, a bath or a diet change — turns a string of separate vet visits into a clear picture. That history is often what lets your vet finally pin down the allergy or trigger and stop the cycle for good.
Break the ear-infection cycle
Tavi lets you log each ear flare-up, medications and grooming so patterns — like a seasonal or post-swim trigger — become obvious, giving your vet the history they need to find the real cause. Free for your first pet.
Frequently asked questions
How do I know if my dog has an ear infection?
Look for head shaking, scratching or rubbing the ears, redness and swelling, odor, and dark or pus-like discharge. Your dog may show pain when the ear is touched. Because the signs overlap with ear mites and other issues, a vet should examine a swab to choose the right treatment.
Can a dog ear infection go away on its own?
It's unlikely and not worth waiting on. Ear infections are painful and tend to worsen or become chronic without treatment, and can spread to the middle ear. They need a vet exam, the correct medication, and treatment of the underlying cause such as allergies.
Why does my dog keep getting ear infections?
Recurring ear infections are usually a sign of an underlying trigger, most often allergies (food or environmental). Ear anatomy, trapped moisture from swimming, ear mites, or conditions like hypothyroidism can also be responsible. Addressing that root cause is the only way to stop the cycle.
What can I clean my dog's ears with?
Use a veterinary-approved ear cleaner, not water, alcohol, hydrogen peroxide or human products, and never push cotton swabs deep into the canal. If the ear is already red, painful or discharging, have your vet check it first, since cleaning a ruptured eardrum with the wrong product can cause harm.
Are dog ear infections contagious?
The yeast and bacteria behind most ear infections are not contagious to other pets or people. Ear mites, however, are contagious between animals, especially in puppies and multi-pet homes, which is one reason your vet checks a swab to identify the cause.
Tavi's guides are informational and not a substitute for professional veterinary advice, diagnosis or treatment. When in doubt, call your veterinarian. Sources: American Kennel Club (AKC); VCA Animal Hospitals; Merck Veterinary Manual; American College of Veterinary Dermatology