Dog Health • Ears

My dog is scratching his ears and they smell bad. Why?

Head shaking, scratching, redness, discharge, and odor are common signs of otitis externa—an inflamed ear canal that may involve yeast, bacteria, allergy, parasites, or foreign material.

Veterinarian reviewedUpdated Aug 20, 2026
The key takeaway

Ear drops should match what is happening in the ear. Reusing old medication without checking the eardrum and current infection can be unsafe.

Why ear infections recur

Allergic skin disease is a major underlying cause of recurrent otitis in dogs. Ear shape, moisture, endocrine disease, narrowed canals, and chronic inflammation can contribute. Yeast and bacteria are often secondary problems rather than the original trigger.

How the ear is evaluated

A veterinarian may inspect the canal and eardrum with an otoscope and examine ear debris under the microscope. Cytology helps determine whether yeast, cocci, rods, or inflammatory cells are present.

When is it urgent?

Severe pain, a swollen ear flap, head tilt, loss of balance, neurologic signs, or rapidly worsening swelling needs prompt care. A grass awn or other foreign body is particularly important when signs start suddenly in one ear.

Cleaning at home

Use only a veterinary-recommended ear cleaner and technique. Cotton swabs pushed deep into the canal can pack debris farther in. Alcohol or peroxide may sting inflamed tissue and is not a universal treatment.