This guide is built on the Merck Veterinary Manual's entry on ear infections and otitis externa, VCA Animal Hospitals' overview of otitis externa, and the AKC's guide to dog ear infections.
"Ear infection" covers a range of severity, from a mild one-off to a recurring problem that needs real investigation-so instead of one generic list of symptoms, this guide leads with a decision path: what you're seeing, and what that actually means for how soon to act.
First: what am I looking at?
| What you're seeing | What it likely means | What to do |
|---|---|---|
| Occasional head shake, no odor, no discharge, ear looks normal | Probably nothing, or minor debris | Watch for 24-48 hours; clean gently if buildup is visible |
| Head shaking/scratching, mild odor, some brown or yellow discharge, ear looks a bit red | Likely a developing infection | Vet visit within a few days-this is the "vet this week," not "vet tonight," category |
| Ear is painful to touch, significantly swollen, heavy discharge, strong odor, dog is clearly distressed | Established infection, possibly advanced | Vet visit within 24 hours |
| Head tilt that persists at rest, loss of balance, stumbling, unusual eye movements | Possible inner-ear involvement | Same-day emergency vet visit |
This table is a starting frame, not a diagnosis-when in doubt, the safer call is always the more urgent one.
Why dogs get ear infections so easily
A dog's ear canal isn't a straight shot like a human's-it runs vertically down from the opening, then turns roughly 90 degrees into a horizontal canal leading to the eardrum. That bend is a trap: moisture, wax, and debris that would drain out of a straighter canal instead pool at the turn, creating a warm, damp environment where yeast and bacteria (both normally present in small numbers) can overgrow.
Contributing factors:
- Floppy ears reduce airflow compared to erect ears, keeping the canal warmer and more humid
- Swimming or frequent bathing, introducing water into an already trap-prone canal
- Excess ear hair, which can trap debris in some breeds
- Allergies-environmental or food-related-are a major driver of chronic or recurring infections, because allergic inflammation changes the skin environment inside the canal
- Individual variation in wax/oil production
Why infections keep coming back for some dogs
A single infection is usually straightforward to treat. Recurring infections-more than one or two episodes a year-are a different situation: they're a signal to investigate an underlying cause rather than re-treating the same symptom repeatedly.
Allergies are the biggest single driver. VCA reports that allergies are involved in as many as 43% of ear infection cases, and that ear infections occur in 65-80% of dogs with food allergies-so an itchy dog with repeat ear trouble is a fairly classic allergy presentation, not a coincidence. Hormonal conditions such as hypothyroidism can also cause repeated infections. Anatomy (very narrow or hairy canals) and, less commonly, a foreign body such as a grass awn lodged in the canal round out the usual list.
If this describes your dog, say so explicitly at the visit. "This keeps happening" changes what your vet tests for-it moves the conversation from "treat this infection" to "find out why this dog keeps getting them," which is the only version that actually reduces the frequency.
Cleaning ears safely at home
Routine cleaning-not treating an active infection, which needs a vet-matched product-is a reasonable preventive habit for dogs prone to buildup, especially floppy-eared breeds and frequent swimmers.
- Use a vet-approved ear cleaner-not water, alcohol, or homemade solutions, which can irritate sensitive tissue.
- Fill the canal per the product's instructions and massage the base of the ear for several seconds; you'll typically hear a squelching sound as it loosens debris.
- Let your dog shake their head-this is a normal, useful part of the process.
- Wipe the visible ear and canal opening with a cotton ball or soft cloth. Never push a cotton swab down into the canal-given the L-shaped anatomy above, this tends to pack debris deeper against the eardrum rather than remove it, and risks injuring the canal lining.
- Stop and call your vet if the ear is painful to touch, shows real redness or discharge, or your dog resists far more than usual-these mean the ear needs an exam, not more aggressive cleaning.
What happens if an ear infection goes untreated
This is the part that justifies not waiting it out. Per VCA, untreated or repeatedly under-treated ear infections can lead to an aural haematoma (bleeding within the ear flap, usually from violent head shaking, which often needs its own surgical treatment), and deep infections can damage or rupture the eardrum, progressing to an internal ear infection and, in some cases, permanent hearing loss. A head tilt, circling, balance problems, or unusual eye movements suggest the middle or inner ear is involved-that's a same-day call, not a wait-and-see.
The practical takeaway: the cost of getting a mild ear checked early is one appointment. The cost of leaving it is sometimes surgery or permanent hearing damage.
Prevention
- Dry ears thoroughly after swimming or bathing, especially in floppy-eared or hairy-eared dogs
- Routine cleaning on a schedule your vet recommends for your specific dog-there's no universal interval
- Address underlying allergies if your dog has them, since untreated allergic skin disease is a common driver of repeat infections
- Don't over-clean "just in case"-frequent unnecessary cleaning can itself irritate the canal
FAQ
Can I just use a leftover ear medication from a previous infection?
Not recommended. A new episode may have a different cause, an antibiotic or antifungal that doesn't match the current problem won't work, and repeated off-label use can contribute to resistant infections that are harder to treat later.
Is it normal for my dog's ears to smell a little?
Some mild, non-offensive odor can be normal. A distinct, worsening, or "off" smell is a sign worth checking, not something to wait out.
Are some breeds just more prone to ear infections?
Yes-breeds with floppy ears, heavy ear hair, or frequent swimming (many retrievers and spaniels, for example) see more ear infections as a group, though any individual dog's risk depends on their specific ears, allergies, and lifestyle.
My vet diagnosed my dog with an ear infection caused by allergies-what now?
Treating the current infection is step one; managing the underlying allergy (through diet trials, environmental management, or medication depending on the type) is what actually reduces how often it comes back. Ask your vet whether an allergy workup makes sense given how often this has happened.