A dog ear infection is inflammation of the ear canal — most often otitis externa, the outer canal — driven by yeast, bacteria, or both multiplying in a warm, humid canal. In Canada it is one of the most common reasons dogs are booked into clinics in Toronto, Vancouver, Montréal and Calgary, and it is also one of the most recurrent: treat the infection, skip the underlying cause, and it comes back. This guide is the hub for our Canadian ear series — what the infection is, what triggers it here, how it is treated, and what you can do between vet visits.
What a dog ear infection actually is
A dog's ear canal is L-shaped: it runs down, then turns inward toward the eardrum. That bend traps moisture, wax and debris, and it makes the canal a far better incubator than a human ear. When the skin lining that canal becomes inflamed — usually from allergy, moisture or a foreign body — the resident microbes take advantage. Malassezia pachydermatis yeast and bacteria such as Staphylococcus pseudintermedius are normal residents that overgrow once conditions favour them (Bond et al., 2020).
In a retrospective series of 100 canine otitis externa cases, underlying allergic skin disease was the single most common primary cause (Saridomichelakis et al., 2007). That matters more than any other sentence in this guide: the yeast is usually the consequence, not the starting point.
The four types Canadian owners run into
- Yeast (Malassezia): brown, waxy, sweet-smelling discharge. The most common by far — see brown discharge in a dog's ear.
- Bacterial: yellow-green, often wetter and more painful. The two are told apart under a microscope — our yeast vs. bacterial comparison walks through it.
- Ear mites: dry, dark, coffee-ground debris and intense itching; contagious, and far more common in puppies and rescues. See ear mites vs. ear infection.
- Middle and inner ear: head tilt, stumbling, flicking eyes. This one is urgent — read inner ear infection symptoms.
Symptoms: what to look and smell for
Head shaking, scratching at one ear, rubbing the head along the couch, a yeasty or sour odour, redness inside the flap, brown or yellow discharge, and pain when the ear is touched. A dog that yelps when you lift the flap has a sore, inflamed canal — not a dirty one. Our full dog ear infection symptoms guide and the at-home ear check cover the whole checklist.
The Canadian ear-infection calendar
Recurrence in Canada tends to follow the seasons rather than bad luck. Recognising your dog's pattern is the fastest route to breaking it.
| Season | What drives ears here | What helps |
|---|---|---|
| Spring (thaw, tree pollen) | Allergic flare-ups begin; damp walks, muddy paws | Dry ears after wet walks; start inside-out support early |
| Summer (lake and cottage season) | Swimming in Muskoka, the Lower Mainland, the Prairie lakes — water sits in the canal | Dry the canal after every swim; check ears weekly |
| Autumn (ragweed, wet leaves) | Peak allergy season in much of Ontario and Québec | Watch for the first head shake; act before discharge appears |
| Winter (furnace-dry indoor air) | Dry, irritated skin barrier; more scratching, more canal trauma | Skin-barrier support; humidify; avoid over-cleaning |
Unlike the summer-swimming story that dominates most articles, Canadian winter is not a free pass — a compromised skin barrier is still a route into otitis.
How dog ear infections are treated
A veterinarian looks into the canal with an otoscope, then examines a swab under a microscope (cytology) to identify yeast, bacteria or mites. That step decides the medication — antifungal, antibiotic, or both — and it is why leftover drops from last year are a poor idea. Nuttall (2016) frames successful management as treating the infection and the underlying cause together. See our Canadian treatment guide, and when antibiotics are actually needed.
In Canada, medically important antimicrobials require a prescription and an established veterinarian–client–patient relationship, and telemedicine rules vary by province — so a virtual consult may or may not be enough to get drops for your dog where you live.
What you can safely do at home
Gentle cleaning with a proper ear cleaner, thorough drying after swimming, and never pouring anything into an ear that might have a ruptured eardrum — you cannot see the eardrum from the outside. Hydrogen peroxide, undiluted vinegar and oils do not belong in a sore canal. Our home remedies guide and evidence-graded natural remedies separate what is reasonable from what is folklore. If cost is the barrier right now, this guide to Canadian low-cost options lists SPCA community clinics, teaching hospitals and the Farley Foundation route.
Supporting the skin from the inside
Because most recurrent ear yeast sits downstream of allergic skin disease, topical treatment alone often leaves the cycle intact. Alongside your vet's plan, our Yeast Infection Drops are formulated as daily inside-out support for dogs prone to yeast overgrowth — made in North America under GMP, with a certificate of analysis on every batch and free shipping worldwide. They are supportive care, not a replacement for prescribed medication. More options sit in our yeast relief collection, and for the topical side see our guide to antifungal ear drops for dogs.
When to see your veterinarian
Book an appointment if you see discharge or smell an odour, if your dog is in obvious pain, if both ears are affected, or if signs last more than a day or two. Go the same day for a head tilt, loss of balance, flicking eyes, bleeding, sudden deafness, or a swollen ear flap (an aural haematoma). Untreated otitis can damage the eardrum and progress to the middle and inner ear.
FAQ
Can a dog ear infection clear up on its own?
Rarely. Mild irritation from a single swim may settle, but an established infection usually progresses. Waiting tends to cost more than an early visit.
Why does my dog keep getting ear infections?
Almost always an untreated primary cause — most often allergic skin disease, sometimes anatomy (floppy ears, hairy canals) or repeated swimming. Treating only the flare keeps the cycle running.
What does a dog ear infection smell like?
Yeast infections smell sweet, musty or slightly like bread; bacterial infections tend to smell sharper and more putrid.
Are some Canadian breeds more prone to it?
Breed matters more than country: Cocker Spaniels, Basset Hounds, Labradors, Golden Retrievers, Poodles and Shar-Peis top the list, thanks to floppy ears, hairy canals or allergy-prone skin.
How long does treatment take?
Uncomplicated cases often improve within 7–14 days of appropriate medication; chronic or recurrent cases need the underlying cause addressed, which takes longer. Recheck as your vet asks — an ear that looks better is not always clear.
Start with our symptoms pillar if you are not sure what you are seeing, and browse the rest of our work on canine skin and coat health at Pure Majesty Pets.
Scientific References
- Saridomichelakis MN, Farmaki R, Leontides LS, Koutinas AF. Aetiology of canine otitis externa: a retrospective study of 100 cases. Vet Dermatol. 2007;18(5):341-347.
- Bond R, Morris DO, Guillot J, et al. WAVD Clinical Consensus Guidelines: Malassezia dermatitis in dogs and cats. Vet Dermatol. 2020;31(1):27-e4.
- Nuttall T. Successful management of otitis externa. In Pract. 2016;38(S2):17-21.
- Chen TA, Hill PB. The biology of Malassezia organisms and their ability to induce immune responses and skin disease. Vet Dermatol. 2005;16(1):4-26.
This article is for educational purposes and does not replace veterinary advice; consult your veterinarian before starting any treatment or supplement.