Dog Ear Infection Symptoms: Signs & Vet Triage | New Zealand Guide

What are the first signs of an ear infection in a dog?

Otitis externa — inflammation of the outer ear canal — rarely announces itself with one dramatic sign. It shows up as a pattern, and the more boxes your dog ticks in the same week, the likelier it is that something is genuinely growing in there.

• Head-shaking or head-rubbing — often the first thing owners notice.
• Scratching one specific ear, repeatedly. That is more telling than general itchiness.
• Odour from the canal. A healthy ear smells of essentially nothing.
• Discharge: brown and waxy, yellow, greenish or blood-tinged.
• Redness, swelling or heat inside the pinna and at the canal opening.
• Flinching when you touch an ear your dog previously let you handle.
• Changed behaviour — restlessness, poor sleep, dislike of being petted near the head.

Dogs are quietly stoic about ear pain, so behavioural signs usually precede anything you can see. If your dog is itchy elsewhere too, the ears may be one symptom of a wider allergic flare — our broader breakdown of the signs of ear infection in dogs covers that overlap.

What does a dog ear infection look and smell like?

Lift the flap in good light. A normal canal opening is pale pink, carries a little light-brown wax and does not smell. An infected one looks wet, red and cluttered with debris — and the smell usually reaches you first.

Owners describe yeast-heavy ears as sweet, musty or corn-chip-like, and bacterial ears as sharper or fouler. Useful, not diagnostic: many infections involve both organisms, and odour has never been a reliable way to choose a medication. Use the table to triage what you see, not to name the bug.

Yeast or bacterial — can you tell at home?

Honestly, no. Malassezia pachydermatis is a yeast that lives in small numbers on normal canine skin and blooms when the canal turns warm, damp or inflamed. Bacteria such as Staphylococcus pseudintermedius — and, in chronic or previously treated ears, Pseudomonas aeruginosa — tend to join it rather than replace it. A retrospective series of 100 dogs with otitis externa found staphylococci and Malassezia among the organisms most frequently recovered, commonly together (Saridomichelakis et al., 2007).

That mix is why guessing costs money: an antifungal does nothing to a rod-shaped bacterium, and an antibiotic does nothing to yeast. Ear cytology — a swab, a stain, two minutes under a microscope — turns the guess into a plan.

Why the otoscopic exam and ear cytology are not optional

Two things happen at that appointment that cannot happen at your kitchen table.

The otoscopic examination checks whether the tympanic membrane is intact. The Merck Veterinary Manual is explicit that this should be verified before topical treatments are applied, because many agents — aminoglycosides in particular — carry ototoxic potential, and the risk is greater when the membrane is not intact. You cannot see a ruptured eardrum from outside, which is exactly why pouring a home solution into a painful ear gambles with your dog's hearing and balance.

Cytology then identifies what is actually growing. Merck's guidance is that diagnosis rests on history, otoscopic examination and cytological evaluation, and that products should be chosen on those results — gram-negative rods, for instance, may call for a different drug class. Cornell adds that debris packed deep in the canal blocks medication from reaching the infection, can inactivate certain drugs, and can make it impossible for your veterinarian to assess the eardrum at all.

Can I treat it at home, or do I need a vet?

While you wait for the appointment: keep the ear dry, stop your dog scratching it raw, note when the signs started, and leave the canal alone. Avoid entirely, per Cornell — hydrogen peroxide and alcohol-based solutions, which sting inflamed tissue and leave residue; undiluted vinegar; and cotton swabs, which push debris deeper. One most owners have never heard: do not push the bottle tip in and squeeze hard, because a pressure seal can rupture the eardrum on its own.

How do I prevent the next one?

Prevention is unglamorous and it works. Dry the ears after every swim, bath and rainy walk. Inspect both ears weekly so you know your dog's normal. Clean when there is something to clean — Cornell suggests roughly every one to two weeks for dogs prone to trouble, and only when debris is visible for a dog with healthy ears, since over-cleaning strips protective cerumen and irritates the lining. And treat any repeat infection as a question about the underlying cause, usually atopic dermatitis or food allergy, rather than bad luck.

For the cleaning step, our dog ear cleaner is built as a dedicated otic solution rather than a saline rinse: a 120 mL vet-strength formula with 0.2% salicylic acid to soften and lift wax, 10% aloe ferox with panthenol (pro-vitamin B5) to soothe the canal skin, and phytosphingosine to support the ear's own barrier. It is chlorhexidine-free — which matters mainly because a non-stinging cleaner is one your dog tolerates for months instead of one you abandon in week two.

Where it sits matters as much as what is in it. This is hygiene: not a treatment for otitis, no substitute for cytology, and never for a painful or unexamined ear. Used the other way round — after your veterinarian has cleared the infection, as the routine that keeps the canal dry and low-debris — an ear cleaner for dogs is one of the few things you control between appointments. The rest of the range sits in our dog ear and eye care collection, and the full routine lives in our guide to dog ear health.

Frequently asked questions

What are the first signs of an ear infection in a dog?

Head-shaking, scratching or rubbing one ear, and a faint sour or musty odour — usually before discharge is visible. Redness inside the flap and sensitivity to touch follow within a day or two.

What does a dog ear infection smell like?

Most owners describe a sweet, musty, corn-chip odour, which leans yeast, or a sharper, fouler smell, which leans bacterial. Odour cannot confirm the organism, and mixed infections are common — it is a reason to book an exam, not to pick a product.

Can a dog ear infection clear up on its own?

Unlikely. Whatever tipped the canal out of balance — allergy, trapped moisture, ear conformation — is usually still there, so infections persist or return. Early treatment is shorter, cheaper and far less painful than waiting.

Is a head tilt in a dog an emergency?

Treat it as one. A persistent head tilt with stumbling, circling or rapid eye movements suggests otitis interna and peripheral vestibular disease, and warrants same-day veterinary attention. Put no liquid into that ear before it is examined.

References

1. O'Neill DG, Volk AV, Soares T, Church DB, Brodbelt DC, Pegram C. Frequency and predisposing factors for canine otitis externa in the UK. Canine Medicine and Genetics. 2021;8:7. doi:10.1186/s40575-021-00106-1 (PMC8422687).
2. Merck Veterinary Manual. Otitis Externa in Animals, ear disorders section (professional edition).
3. Hoff S; reviewed by Carney P. Otitis Media and Interna in Animals. Merck Veterinary Manual, revised December 2025.
4. Cohen A. How to Clean Your Dog's Ears. Cornell University College of Veterinary Medicine, Riney Canine Health Centre; updated October 2025.
5. Saridomichelakis MN, Farmaki R, Leontides LS, Koutinas AF. Aetiology of canine otitis externa: a retrospective study of 100 cases. Veterinary Dermatology. 2007;18(5):341–347.
6. Bond R, Morris DO, Guillot J, et al. Malassezia dermatitis in dogs and cats: WAVD Clinical Consensus Guidelines. Veterinary Dermatology. 2020;31(1):27-e4.

Reviewed by the Pure Majesty Pets research team, July 2026. For education only; it does not replace a veterinary examination. Ear infections are diagnosed with an otoscopic exam and cytology — pain, discharge, a head tilt or balance changes should be assessed by your veterinarian. Routine ear cleaners support healthy ears and do not diagnose, treat, cure or prevent disease.