Symptoms & Diagnosis

Why Does My Dog Keep Getting Ear Infections? Causes, Treatment, and Prevention

By Emiel Maddens · Reviewed in consultation with licensed veterinary professionals · Updated April 2026 · 10 min read

Dog shaking head, a common sign of ear infection or ear discomfort

Key Takeaways

Up to 80 percent of recurring ear infections in dogs are driven by an underlying allergy, most often atopic dermatitis.
The ear canal is an extension of the skin, so dogs with skin allergies almost always have ear involvement too.
Yeast (Malassezia) and bacteria (Staphylococcus, Pseudomonas) are the organisms that cause the infection, but they are not the root cause. They are opportunistic invaders that thrive once the ear environment changes.
Floppy-eared breeds and breeds with narrow or hairy ear canals are anatomically predisposed to infections.
Preventing recurrence requires treating the underlying allergy, not just repeatedly clearing the infection.

A single ear infection is common and usually straightforward to treat. But when the infections keep coming back, month after month, something deeper is going on. Veterinary dermatologists estimate that allergies drive the majority of recurring ear infections in dogs, yet many of these dogs are treated with round after round of ear drops without anyone investigating the underlying trigger.

This guide focuses on the why behind recurrent otitis, not just the what. Understanding the difference between a primary cause (the thing that changes the ear environment) and a secondary cause (the infection that moves in afterward) is the key to breaking the cycle. If your dog has had more than two or three ear infections in a year, this distinction matters.

Why Ear Infections Keep Coming Back

Veterinary dermatologists divide ear infection causes into primary factors (what starts the problem), predisposing factors (what makes certain dogs more vulnerable), and perpetuating factors (what keeps the cycle going once it starts).

1. Environmental Allergies (Atopic Dermatitis)

Atopy is the most common primary cause of recurrent otitis externa in dogs. Allergic inflammation causes the lining of the ear canal to swell, produce excess cerumen (wax), and shift from a dry, self-cleaning environment to a warm, moist one. This altered environment allows yeast and bacteria to overgrow. Many atopic dogs show ear symptoms before any other skin signs, so recurrent ear infections can be the first clue to an underlying allergy.

2. Food Allergies

Food-allergic dogs frequently present with otitis as their primary or only symptom. One study found that up to 80 percent of food-allergic dogs had concurrent ear disease. The ear involvement tends to be bilateral (both ears) and non-seasonal. If your dog's ear infections happen year-round and do not fluctuate with the seasons, food allergy should be investigated with a strict elimination diet trial.

3. Ear Anatomy

Dogs with long, floppy ears (Cocker Spaniels, Basset Hounds, Cavalier King Charles Spaniels) have reduced airflow to the ear canal, which traps heat and moisture. Breeds with narrow or stenotic ear canals (Shar-Pei, Bulldogs) have less room for ventilation and drainage. Breeds with excessive hair growth in the ear canal (Poodles, Schnauzers) can have further reduced airflow. These anatomical factors do not cause ear infections on their own, but they dramatically lower the threshold.

4. Yeast Overgrowth (Malassezia)

Malassezia pachydermatis is the most common organism in yeast ear infections. It thrives in warm, waxy, low-oxygen environments. Yeast otitis typically produces a brown, waxy discharge with a characteristic musty or sweet smell. It responds well to topical antifungals, but will return if the underlying allergy continues to alter the ear environment.

5. Bacterial Infections

Staphylococcus and Pseudomonas are the bacteria most commonly cultured from infected dog ears. Staphylococcus infections tend to be milder and more treatable. Pseudomonas infections are more aggressive, often produce a greenish or foul-smelling discharge, and have a higher rate of antibiotic resistance. Any ear infection that fails to respond to initial treatment should have culture and sensitivity testing performed.

6. Moisture and Swimming

Water in the ear canal disrupts the natural waxy barrier and creates a favorable environment for microbial growth. Dogs that swim regularly are at significantly higher risk of ear infections. Drying the ears thoroughly after every swim or bath, and using a veterinarian-recommended ear drying solution, can substantially reduce this risk.

Veterinarian examining a dog's ear canal with an otoscope

Which Breeds Are Most Affected?

Certain breeds are overrepresented in veterinary dermatology clinics for ear infections due to anatomy, allergy predisposition, or both:

Cocker Spaniel: Heavy, pendulous ears that trap moisture, combined with excess sebum production that feeds yeast and bacteria.
Cavalier King Charles Spaniel: Long, floppy ears and a high rate of atopic dermatitis make this breed one of the most ear-infection-prone.
Labrador Retriever: Loves water, has floppy ears, and has one of the highest rates of atopic dermatitis in any breed.
Golden Retriever: Water-loving breed with a dense coat, floppy ears, and strong genetic predisposition to allergies.
Shar-Pei: Extremely narrow, stenotic ear canals that trap moisture and debris, with minimal airflow.
English Bulldog: Narrow ear canals, high allergy rates, and a compromised immune system make ear infections chronic for many Bulldogs.
French Bulldog: Narrow ear canals and very high rates of atopic dermatitis drive frequent ear problems.
Poodle: Excessive hair growth in the ear canal reduces airflow and traps moisture and debris.
German Shepherd: Genetic predisposition to allergies and a tendency toward bacterial ear infections, including resistant strains.
Basset Hound: The longest, heaviest ears of any breed, combined with naturally oily skin, create ideal conditions for infection.

How to Check Your Dog's Ears at Home

Regular ear checks can catch problems early. Here is what to look for between vet visits:

Lift the Ear Flap and Look

Healthy ear tissue is pink, smooth, and has minimal wax. Redness, swelling, or excessive wax production are early signs of a problem. Compare both ears, as allergic ear disease is usually bilateral (both sides affected equally).

Smell the Ears

Healthy ears have no strong odor. A sweet, musty, or bread-like smell suggests yeast. A foul, pungent, or fishy smell suggests bacteria, possibly Pseudomonas. Any noticeable odor from the ears warrants a closer look.

Observe the Discharge

Light tan or golden wax in small amounts is normal. Dark brown, waxy discharge is typical of yeast infections. Yellow or greenish discharge suggests bacterial infection. Bloody or black discharge needs immediate veterinary attention.

Watch Your Dog's Behavior

Head shaking, ear scratching, tilting the head to one side, rubbing ears on furniture, or crying when the ears are touched are all signs of ear discomfort. Some dogs paw at their ears or become irritable when their ears bother them.

See your vet urgently if:

Head tilt that does not resolve, which may indicate middle or inner ear involvement
Loss of balance, circling, or abnormal eye movements (nystagmus), indicating possible inner ear infection
Severely swollen ear canal that appears almost closed (stenosis), which may require surgical intervention
Ear infection that has not responded to two different prescribed treatments
Bloody or black discharge from the ear canal
Facial nerve paralysis (drooping lip or eyelid on the affected side)

Treatment and Management

Breaking the cycle of recurrent ear infections requires treating both the current infection and the underlying cause:

Treating the Active Infection

Your veterinarian will examine a sample of ear discharge under the microscope (cytology) to determine whether yeast, bacteria, or both are present. This guides treatment selection. Yeast infections respond to topical antifungals (miconazole, clotrimazole). Bacterial infections require topical antibiotics, and in resistant cases, culture-guided systemic antibiotics. Mixed infections need combination products.

Ear Cleaning

Regular ear cleaning with a veterinarian-recommended ear cleanser removes debris, excess wax, and microbial biofilm. During active infections, the vet may perform a deep ear flush. At home, follow the cleaning schedule your vet recommends, typically weekly for maintenance in infection-prone dogs.

Addressing the Underlying Allergy

Since allergies drive most recurrent ear infections, long-term management of the allergy is essential. This may include allergen-specific immunotherapy, Apoquel, Cytopoint, or dietary changes if food allergy is confirmed. Managing the allergy reduces ear canal inflammation, which removes the conditions that allow yeast and bacteria to overgrow. Our Dog Allergy Testing Guide explains the diagnostic options.

Topical Antimicrobial Maintenance

For dogs with a history of frequent ear infections, a maintenance protocol of regular ear cleaning combined with periodic topical antimicrobial treatment can extend the time between flare-ups. Our Itchy Skin Relief Spray contains chlorhexidine, which is effective against both yeast and bacteria commonly found in ear infections.

Surgical Options for Severe Cases

Dogs with chronically stenotic (narrowed) ear canals, end-stage otitis, or recurrent infections that fail all medical management may benefit from surgery. Total ear canal ablation (TECA) removes the diseased ear canal and is a last-resort option that can dramatically improve quality of life for dogs with severe, untreatable chronic otitis.

Ears red, waxy, or smelly? Start here.

An antimicrobial spray can help manage yeast and bacterial overgrowth between vet visits and extend the time between ear infection flare-ups. Our Itchy Skin Relief Spray combines chlorhexidine with soothing agents and can be used on the outer ear and ear flap.

Shop Itchy Skin Relief Spray

Related Conditions

This symptom can be a sign of several underlying conditions. Our in-depth guides cover each one:

Atopic Dermatitis in Dogs, the most common underlying cause of recurrent ear infections
Fungal Skin Infections in Dogs, Malassezia yeast is the most common organism in dog ear infections
Dog Ear Infection Treatment Guide, detailed treatment protocols for each type of ear infection
Dog Allergy Testing Guide, identifying the allergy that drives recurrent ear disease
Dog Food Ingredients That Cause Skin Problems, food allergy as a cause of chronic ear infections

Recurring Ear Infection FAQ

Q: How many ear infections per year is considered 'recurrent'?

Most veterinary dermatologists define recurrent otitis as three or more episodes per year, or infections that return within one month of completing treatment. If your dog hits this threshold, the focus should shift from treating individual infections to investigating and managing the underlying cause.

Q: Should I pluck the hair from my dog's ears?

This is debated. Historically, groomers routinely plucked ear hair from breeds like Poodles and Schnauzers. Current veterinary opinion is mixed. Plucking can cause micro-trauma and inflammation that may actually increase infection risk. Many dermatologists now recommend only plucking hair that is visibly obstructing the ear canal or trapping debris, and leaving the rest alone.

Q: Can I use hydrogen peroxide to clean my dog's ears?

Hydrogen peroxide is not recommended for routine ear cleaning. It can irritate the delicate ear canal lining and may cause pain if the eardrum is compromised. Use a veterinarian-recommended ear cleanser with a pH appropriate for the canine ear canal.

Q: Why does my dog get ear infections after swimming?

Water disrupts the natural waxy barrier in the ear canal and creates a moist environment where yeast and bacteria thrive. For swim-prone dogs, drying the ears thoroughly after every water exposure is essential. Some veterinarians recommend a drying ear solution applied after swimming.

Q: Can ear infections cause permanent hearing loss?

Chronic, untreated ear infections can cause permanent changes. Repeated inflammation can thicken the ear canal (stenosis), damage the eardrum, and in severe cases, the infection can spread to the middle and inner ear, potentially causing permanent hearing loss. This is why chronic ear infections should not be left to resolve on their own.

Q: My dog only gets infections in one ear. Why?

Unilateral (one-sided) ear infections are more likely to have a local cause, such as a foreign body (grass awn), a polyp or mass in the ear canal, or trauma. Bilateral infections are more suggestive of a systemic cause like allergies. A one-sided infection that does not respond to treatment warrants an otoscopic examination or imaging.

Q: Are certain ear drops better than others?

The best ear medication depends on what organism is causing the infection. Yeast infections need antifungals. Bacterial infections need antibiotics, and the choice of antibiotic should ideally be guided by culture results. Multi-agent ear products that contain antifungal, antibiotic, and anti-inflammatory components are commonly prescribed for mixed or undiagnosed infections.

Sources

Saridomichelakis MN, Farmaki R, Leontides LS, Koutinas AF. "Aetiology of canine otitis externa: a retrospective study of 100 cases." Veterinary Dermatology. 2007;18(5):341-347.

Rosser EJ Jr. "Causes of otitis externa." Veterinary Clinics of North America: Small Animal Practice. 2004;34(2):459-468.

Favrot C, Steffan J, Seewald W, Picco F. "A prospective study on the clinical features of chronic canine atopic dermatitis and its diagnosis." Veterinary Dermatology. 2010;21(1):23-31.

Noli C, Saridomichelakis MN, et al. "Guidelines for the treatment of recurrent otitis externa in dogs." Veterinary Dermatology. 2014;25(4):290-e72.

Morris DO. "Medical therapy of otitis externa and otitis media." Veterinary Clinics of North America: Small Animal Practice. 2004;34(2):541-555.