Understanding Dog Ear Infections: Signs, Causes, and Prevention

Ear infections are one of the top 5 reasons dogs visit the vet. They’re painful, recurring, and surprisingly easy to prevent once you understand what causes them. Here’s the practical guide.

How to Tell Your Dog Has an Ear Infection

Dogs can’t tell you their ear hurts, but they’re not subtle about showing it:

Head shaking (persistent, not the occasional post-nap shake)
Scratching at the affected ear repeatedly
Redness or swelling visible inside the ear flap
Discharge that’s brown, yellow, or bloody
Odor from the ear canal (healthy ears don’t smell)
Tilting the head to one side
Whimpering or pulling away when you touch the ear area
Loss of balance or circling (indicates the infection has reached the middle or inner ear, which is a veterinary emergency)

If you see discharge, smell an odor, or your dog is shaking their head more than a few times a day, schedule a vet visit. Ear infections don’t resolve on their own and get worse without treatment.

What Causes Ear Infections

Moisture

Water trapped in the ear canal after swimming or bathing creates a warm, humid environment where bacteria and yeast thrive. This is the most common trigger in dogs that swim regularly.

Allergies

Food allergies and environmental allergies (pollen, dust mites, mold) are the leading underlying cause of chronic, recurring ear infections. The allergic response causes inflammation in the ear canal, which disrupts the normal skin barrier and allows opportunistic bacteria and yeast to overgrow.

If your dog gets ear infections more than twice a year, allergies are the likely root cause. Treating the individual infections without addressing the allergy is like mopping the floor while the faucet runs.

Ear Anatomy

Dogs with long, floppy ears (Basset Hounds, Cocker Spaniels, Bloodhounds, Beagles) trap more moisture and have less air circulation in the ear canal. Dogs with narrow ear canals (Shar Peis, Bulldogs) have reduced airflow and are prone to debris buildup.

Excess Hair in the Ear Canal

Breeds like Poodles, Shih Tzus, and Bichon Frises grow hair inside the ear canal. This hair traps moisture and debris. Some groomers routinely pluck this hair, though there’s debate about whether plucking causes more inflammation than it prevents. Ask your vet for a breed-specific recommendation.

Foreign Bodies

Grass seeds (foxtails) are a common culprit in dogs that spend time in fields or tall grass. A foxtail that enters the ear canal causes immediate irritation and can migrate deeper if not removed by a vet.

Types of Ear Infections

Type	Location	Severity
Otitis externa	Outer ear canal	Most common, treatable at home with vet-prescribed medication
Otitis media	Middle ear	More serious, requires veterinary treatment, sometimes sedated cleaning
Otitis interna	Inner ear	Least common, affects balance and hearing, can become chronic

Most ear infections are otitis externa. If treated early, they resolve within 1 to 2 weeks of topical medication. Untreated, they can progress to the middle and inner ear, where treatment becomes more complex and expensive.

Treatment

What the Vet Does

Your vet will examine the ear canal with an otoscope, take a swab for cytology (looking at the cells under a microscope to determine if the infection is bacterial, yeast, or both), and prescribe appropriate medication.

Typical treatment includes:

Ear cleaner to flush debris from the canal
Topical medication (drops or ointment) containing antibiotics, antifungals, or both, often combined with a steroid to reduce inflammation
Oral medication for severe or deep infections

Treatment duration is usually 7 to 14 days. Complete the full course even if the ear looks better after a few days. Stopping early is the primary cause of resistant, recurring infections.

What You Should NOT Do

Don’t use hydrogen peroxide. It damages healthy tissue in the ear canal and makes inflammation worse.
Don’t use rubbing alcohol. On inflamed or raw ear tissue, alcohol causes intense pain.
Don’t use cotton swabs deep in the canal. You can’t see the eardrum, and pushing debris deeper packs it against the drum. Clean only the parts of the ear you can see.
Don’t use leftover medication from a previous infection. The current infection may be a different type (bacterial vs. yeast) requiring different medication.

Prevention

Dry the Ears After Water Exposure

After swimming or bathing, use a soft cloth or cotton ball to gently dry the visible part of the ear. For dogs that swim frequently, a vet-approved ear drying solution applied after each swim prevents moisture buildup. These solutions typically contain a drying agent that evaporates trapped water.

Regular Ear Checks

Once a week, look inside your dog’s ears. Healthy ears are pink, clean, and have no odor. If you see wax buildup, a small amount is normal (similar to human ears). Dark brown or black discharge, redness, or swelling means something is wrong.

Address Underlying Allergies

If your dog has recurring ear infections (three or more per year), talk to your vet about allergy testing and management. This might involve:

A dietary elimination trial to identify food allergies
Allergy medication (apoquel, cytopoint) for environmental allergies
Regular ear cleaning with a medicated solution to maintain a healthy ear environment

Treating the allergy reduces ear infections dramatically. Many dogs with chronic ear infections see the infections stop entirely once their allergies are managed.

Keep Ears Clean Between Infections

A gentle ear cleaner used weekly or biweekly keeps the ear canal clear of wax and debris. Your vet can recommend a product appropriate for your dog. Avoid over-cleaning, which can strip natural oils and cause irritation.

Breed-Specific Risk

Higher Risk	Why
Cocker Spaniels	Narrow ear canals, heavy floppy ears
Basset Hounds	Long ears that trap moisture
Shar Peis	Narrow, folded ear canals
Labrador Retrievers	Swimmers with floppy ears
French Bulldogs	Narrow canals, allergic tendencies
Poodles	Hair growth in ear canal
Golden Retrievers	Swimmers, allergy-prone

Frequently Asked Questions

How much does treating an ear infection cost?

A basic ear infection visit (exam, cytology, medication) typically runs $100 to $250. Chronic or severe infections requiring sedated ear cleaning, culture, and sensitivity testing can cost $300 to $600. Recurring infections with allergy workup can total $500 to $1,500 over the diagnostic period.

Can ear infections cause permanent hearing loss?

Repeated or severe middle/inner ear infections can damage the structures responsible for hearing. A single outer ear infection treated promptly almost never affects hearing. Chronic, untreated infections are the risk. This is another reason to treat early and address underlying causes.

My dog’s ears smell terrible but there’s no discharge. Is it still an infection?

Possibly. Yeast overgrowth can produce a strong musty or sweet odor before visible discharge appears. If the smell persists for more than a day or two, have your vet check. Early yeast overgrowth is easier to treat than a full infection.