Glossary

Ear infection

Inflammation of the outer ear canal, often with yeast or bacteria, causing head shaking, scratching, odor and pain.

Also called: otitis externa, otitis, dog ear infection, yeast infection in ears, smelly ears

Otitis externa is inflammation of the ear canal that runs from the flap to the eardrum. Yeast and bacteria move in once the canal is irritated, and the trigger is often something else underneath, most commonly allergy, plus moisture from swimming, mites or a foreign object such as a grass seed.

Signs include head shaking, scratching, a bad smell, dark or yellow discharge, redness and a dog that yelps when the ear is touched. Dogs with floppy ears or hairy canals, such as the Cocker Spaniel and Basset Hound, get them often.

See a veterinarian before putting anything into the ear, as a ruptured eardrum changes which products are safe. Repeat infections point to an underlying cause that needs investigating, and untreated ones can spread to the middle ear.

Last reviewed November 8, 2026

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Related terms

Atopic dermatitis An inherited tendency to develop itchy skin and ear disease from allergens in the environment such as pollen, dust mites and molds. Food allergy An immune reaction to a protein in the diet that usually causes itchy skin and ear problems, and sometimes digestive upset. Hot spot A fast-appearing, red, wet and painful patch of skin that a dog creates by licking or scratching, usually because of an underlying irritation.