Ear Infections (Otitis Externa)

Otitis externa is inflammation of the external ear canal. In dogs, the ear canal has an L-shape (vertical canal leading to a horizontal canal), which traps moisture and debris. Dogs with floppy ears, hairy ear canals, or frequent swimming are at higher structural risk. But the most important underlying cause of recurring ear infections is allergy - particularly atopic dermatitis or food allergy.

A single ear infection that resolves with treatment and doesn't recur may be a one-off. Ear infections that keep coming back, affect both ears, or are associated with generalised skin changes are almost always signalling an underlying condition.

What to monitor

Early signs (before visible infection):

• Head shaking
• Scratching at one or both ears
• Rubbing the head on furniture
• Reluctance to have the head touched

Active infection signs:

• Odour from the ear - yeasty, cheesy, or sweet smell
• Discharge - brown, black, yellow, or white
• Redness or swelling visible at the ear opening
• Pain on ear manipulation
• Tilting the head (head tilt can indicate middle ear involvement)

Weekly check routine: Lift the ear flap and look inside. Normal ears are pale pink, slightly waxy, and odourless. Note any change from normal. A brief weekly check allows you to catch infections early, before they become painful and established.

Logging infection episodes

For each episode, record:

• Date of onset (when you first noticed)
• Which ear(s) affected
• Discharge character and odour
• Whether it's a new infection or recurrence of recent episode
• Treatment used and how quickly it resolved
• Any preceding events (swimming, grooming, dietary change)

Three or more ear infections per year in the same ear is a clear signal that an underlying cause needs to be investigated.

Understanding what's causing it

Yeast (Malassezia): Dark brown, waxy discharge; sweet-sour odour. Very common in allergic dogs. Often affects both ears.

Bacteria (usually Staphylococcus or Pseudomonas): Yellow or green discharge; often more painful. May follow a yeast infection or develop independently.

Mixed infection: Yeast and bacteria coexist commonly. Cytology (a swab examined under the microscope) identifies what's present and guides treatment choice.

Ear mites (Otodectes): Dark, crumbly discharge resembling coffee grounds; more common in young dogs. Highly contagious between pets.

Underlying cause: Allergy, hypothyroidism, or anatomical factors. If this isn't identified and addressed, treatment resolves the current infection but not the susceptibility.

Home care between infections

For dogs prone to ear infections:

• Check ears weekly
• Dry ears thoroughly after swimming or bathing - use a dry cotton ball (not a cotton bud) to absorb moisture from the ear canal opening
• Don't use cleaning solutions unless directed by your vet - cleaning an infected ear can spread the infection
• Your vet may prescribe a maintenance ear cleaner for at-risk dogs; use only as directed

When to contact your vet

Contact your vet promptly if:

• Visible discharge, significant odour, or obvious pain
• Head tilt, loss of balance, or signs of hearing change (these suggest middle or inner ear involvement - more serious)
• Ear has been treated but isn't resolving after the course is complete

Contact your vet routinely if:

• Infections are recurring (three or more times per year)
• You want to investigate an underlying cause

Frequently Asked Questions

Can I clean my dog's ears at home to prevent infections? Maintenance cleaning with a veterinary-approved ear cleaner can help in dogs prone to infections, but only if the ear is currently clear. Cleaning an infected ear can push the infection deeper. If in doubt, have the vet check before cleaning.

Why does my dog keep getting ear infections despite treatment? Recurring infections despite appropriate treatment almost always have an underlying cause - most commonly allergy. Treating each infection without investigating the underlying driver is treating symptoms, not the condition. Ask your vet about allergy investigation.

My dog's ear smells bad but there's nothing visible at the opening. Should I be worried? Yes. The horizontal canal extends deeper than is visible to the naked eye. A smell without visible discharge suggests infection in the deeper canal. A vet examination with an otoscope is needed.

Is it okay to use cotton buds to clean my dog's ears? No. Cotton buds risk pushing debris or infection further into the canal and can damage the delicate ear canal lining. Use cotton balls to wipe the visible outer canal only.

My dog's ears are painful - what can I do before the vet appointment? Keep hands away from the affected ear - handling a painful ear is understandably aversive and can lead to fear or aggression. Avoid swimming until assessed. Don't apply any drops or solutions unless you already have a prescribed product. A same-day appointment is appropriate for significant ear pain.