Ear Infections in Dogs: Causes, Symptoms & Treatment

Vet-reviewed via PetHealth+ · Last reviewed June 2026

Ear infections (otitis externa) cause head shaking, scratching, redness, odour, and discharge in the ear canal. They are often linked to allergies, moisture, or anatomy — especially in floppy-eared breeds. See your vet for diagnosis and prescription treatment; do not use human ear drops or insert cotton swabs deep into the canal.

What causes ear infections in dogs?

The canine ear canal is L-shaped and warm, making it ideal for yeast and bacteria when moisture or inflammation is present. Common triggers include:

Allergies — environmental or food allergies are the leading underlying cause of chronic otitis
Moisture — swimming, bathing, or humid climates without proper drying
Anatomy — long, floppy ears (Cocker Spaniels, Basset Hounds) trap heat and debris
Ear mites — more common in puppies and multi-pet households
Foreign bodies — grass seeds or debris lodged in the canal
Hormonal disorders — hypothyroidism can predispose dogs to skin and ear problems

Infections may involve bacteria (Staphylococcus, Pseudomonas), yeast (Malassezia), or both.

Symptoms to watch for

Signs of otitis externa include:

Frequent head shaking or tilting
Scratching at one or both ears
Red, swollen ear flap or canal opening
Dark brown, yellow, or bloody discharge
Strong yeasty or foul odour
Pain when the ear is touched
Balance problems or hearing changes (suggest deeper involvement)

Chronic untreated infections can spread to the middle ear (otitis media), causing more serious pain and neurological signs.

How vets diagnose and treat ear infections

Your vet will examine the ear with an otoscope, assess the eardrum, and may take a swab for cytology or culture. This identifies whether yeast, bacteria, or mites are present and guides treatment.

Typical treatment includes:

Ear cleaning — professional flush to remove debris (sometimes under sedation if painful)
Topical medication — antibiotic, antifungal, or steroid drops as prescribed
Oral medication — for severe or deep infections
Allergy management — if allergies drive recurrence

Finish the full course of medication even if the ear looks better after a few days. Stopping early is a common reason infections return.

Prevention and home care

Dry ears thoroughly after swimming or bathing
Clean only as directed by your vet — over-cleaning can irritate healthy ears
Manage underlying allergies with your vet’s guidance
Check ears weekly for redness, odour, or discharge
Never use cotton swabs deep in the canal — they push debris inward and risk eardrum damage

Schedule a recheck if symptoms return within weeks of finishing treatment.

Frequently asked questions

How do I know if my dog has an ear infection?

Head shaking, ear scratching, redness, swelling, odour, and brown or yellow discharge are common signs. Your dog may also tilt their head or cry when the ear is touched.

Can I treat my dog's ear infection at home?

Over-the-counter drops are rarely enough and can mask a deeper problem. Always have the ear examined and get appropriate prescription treatment from your vet.

Why do ear infections keep coming back in dogs?

Underlying allergies, anatomy, moisture, or unresolved yeast or bacterial overgrowth often cause recurrence. Your vet may recommend allergy management, ear cleaning protocols, or further testing.

Are ear infections painful for dogs?

Yes. Otitis is uncomfortable to painful, especially in the middle or inner ear. Prompt treatment improves comfort and prevents hearing loss or deeper complications.