Head shaking, ear scratching, and a new odor from your dog’s ear are common reasons to suspect an ear problem. These signs deserve attention, but they do not tell you whether the cause is yeast, bacteria, mites, allergies, or a foreign object. The right treatment depends on what a veterinarian finds inside the ear.
What does an ear infection look like in a dog?
Otitis externa means inflammation of the outer ear canal. A dog may have one or several of these signs:
- Repeated head shaking or scratching at one or both ears.
- Redness, swelling, or tenderness around the ear opening.
- More wax than usual, moist debris, or yellow, brown, or dark discharge.
- A strong or unusual smell from the ear.
- Rubbing the head against furniture or pulling away when the ear is touched.
- Crusts or irritated skin on the ear flap.
Smell or discharge color alone cannot reliably identify a bacterial versus yeast infection. Ear mites are another possibility, especially in younger animals or pets exposed to affected animals. A dog can also have more than one problem at the same time.
When is an ear problem urgent?
Seek prompt veterinary care if your dog is in significant pain, the ear is markedly swollen, or there is bloody discharge. Go to an emergency veterinarian for a new head tilt with loss of balance, abnormal eye movements, severe disorientation, or other neurologic changes. These signs may indicate disease beyond the outer ear and need an in-person examination.
A swollen, pillow-like ear flap can be an aural hematoma caused by repeated shaking. It is not the same thing as an infection and needs veterinary assessment.
Why dogs develop ear infections
Allergies are an important underlying cause of recurring ear inflammation. Moisture, trapped debris, ear-canal anatomy, parasites, and foreign material can also contribute. Bacteria and yeast may overgrow in an inflamed canal, but treating the overgrowth alone may not prevent the problem from returning.
Dogs that swim frequently or have a history of allergies may need an individualized prevention plan. Having floppy ears does not by itself establish the diagnosis.
How a veterinarian checks the ear
A veterinarian will ask about the history, examine the ear flap and canal with an otoscope when possible, and often collect a small sample of debris for ear cytology. Looking at this material under a microscope helps identify yeast, bacteria, and inflammation. In recurrent or difficult cases, additional tests may be appropriate.
The veterinarian also needs to assess whether the eardrum is intact before choosing certain cleaners or medications. An extremely painful or swollen ear may require special handling or sedation for a thorough exam.
What treatment usually involves
Depending on the findings, treatment may include a veterinary ear cleaner, prescription topical medication, and care for an underlying allergy or other cause. There is no one ear drop that is appropriate for every dog. Complete the prescribed course and attend recommended rechecks, even if the ear looks better quickly.
For a more detailed explanation, see how veterinarians treat ear infections and what is safe to do at home.
What can you do safely before the appointment?
- Keep the ear dry and avoid swimming until your veterinarian advises otherwise.
- Do not put cotton swabs deep into the ear canal.
- Avoid vinegar, alcohol, essential oils, hydrogen peroxide, and leftover ear medications.
- Do not force cleaning if your dog is painful; ask the clinic whether any cleaning is appropriate before examination.
- Take note of when symptoms started, whether one or both ears are affected, and any prior treatments.
Frequently asked questions
Can I tell yeast from bacteria by the smell?
No. Odor and appearance overlap. Ear cytology is much more useful for guiding treatment.
Can an ear infection clear on its own?
Some mild irritation may settle, but persistent shaking, pain, redness, or discharge should be examined rather than treated by guesswork.
Does my dog need antibiotics by mouth?
Not necessarily. Many outer-ear problems are managed with topical treatments selected after examination; oral drugs are reserved for particular situations.
Sources
- Merck Veterinary Manual: Otitis externa in animals.
- University of Melbourne: Companion animal ear guidelines.
Educational information only; not a substitute for an examination by a licensed veterinarian.
This article is for general education and is not a substitute for care from your own veterinarian. Learn about The Pet Vet and our editorial policy.