Ear Infections in Dogs: Why They Keep Coming Back

If your dog is shaking her head, scratching at her ears, or producing a smell that makes you wince, an ear infection is the likely culprit. The good news: ear infections are among the most treatable conditions in veterinary medicine. The better news: once you understand the cause, you can often prevent them from coming back.

How Common Are Ear Infections?

Ear infections (otitis) are one of the top 5 reasons dogs visit the vet, affecting an estimated 20% of dogs. They can occur in one or both ears and range from a mild annoyance to a painful, chronic problem.

Dogs are more prone to ear infections than humans because of their ear canal anatomy. The canine ear canal is L-shaped — it goes down vertically, then makes a 90-degree turn horizontally toward the eardrum. This shape traps moisture and debris, creating an environment where bacteria and yeast thrive.

Types of Ear Infections

Otitis externa — infection of the outer ear canal. This is the most common type and what most people mean by "ear infection." It's visible when you look into your dog's ear.

Otitis media — infection of the middle ear (behind the eardrum). Occurs in approximately 50% of chronic otitis externa cases. Harder to diagnose and treat.

Otitis interna — infection of the inner ear. Rare but serious. Can cause loss of balance, head tilt, circling, and nausea.

What Causes Ear Infections?

Ear infections almost always have an underlying cause. Treating only the infection without addressing the root cause guarantees recurrence.

Primary causes:

• Allergies — the #1 underlying cause of chronic ear infections. Environmental and food allergies cause inflammation in the ear canal, changing the environment and allowing bacteria and yeast to overgrow.
• Moisture — water trapped in the ear canal after swimming or bathing creates ideal conditions for infection. This is why ear infections spike in summer.
• Ear anatomy — floppy ears that cover the canal reduce air circulation. Narrow ear canals and excessive hair in the canal also increase risk.
• Foreign bodies — grass awns, foxtails, or other debris lodged in the ear canal.

Perpetuating factors:

• Ruptured eardrum allowing infection to spread deeper
• Ear canal narrowing from chronic inflammation
• Calcified ear canals from long-standing disease
• Resistant bacteria from inappropriate antibiotic use

Common infectious organisms:

• Malassezia (yeast) — the most common, producing a dark, waxy, sweet-smelling discharge
• Staphylococcus and Streptococcus bacteria — producing a yellow or green, foul-smelling discharge
• Pseudomonas — an aggressive, difficult-to-treat bacterium found in chronic cases

Recognizing the Symptoms

Early signs:

• Head shaking (frequent, vigorous)
• Scratching at one or both ears
• Redness visible inside the ear flap
• Mild odor from the ear

Progressive signs:

• Obvious discharge — brown, yellow, or green
• Strong, unpleasant odor
• Swelling of the ear canal
• Pain when the ear is touched — may pull away, whimper, or snap
• Rubbing the affected ear on carpet or furniture

Severe signs:

• Holding the head tilted to one side
• Loss of balance or circling (suggests middle or inner ear involvement)
• Hearing loss
• Bleeding from the ear
• Swollen, hot ear flap

If your dog shows any signs of balance problems, tilting, or circling, see your vet urgently — this may indicate infection has spread beyond the outer ear.

Which Breeds Are Most Prone?

Breed anatomy strongly influences ear infection risk:

• Labrador Retrievers — floppy ears plus love of water = frequent infections
• Cocker Spaniels — heavy, pendulous ears with narrow canals and excess hair. One of the most affected breeds.
• Basset Hounds — extremely long, heavy ear flaps that trap moisture
• Shar-Peis — narrow ear canals due to skin folds
• Poodles and Bichon Frises — excessive hair growth in the ear canal
• Golden Retrievers — floppy ears combined with allergy predisposition

Diagnosis

Your vet will perform:

Otoscopic examination — looking deep into the ear canal with a lighted scope. This reveals inflammation, discharge, foreign bodies, masses, and eardrum integrity.

Ear cytology — a swab of ear discharge examined under the microscope. This determines whether the infection is yeast, bacteria, or both, and guides treatment selection.

Culture and sensitivity — for chronic or resistant infections. A sample is sent to a lab to identify the exact bacterium and which antibiotics will work against it.

Additional tests — if infections recur, your vet may recommend allergy testing, thyroid testing, or imaging (CT scan) to investigate deeper or underlying causes.

Treatment

Treatment depends on the type and severity of infection:

For mild to moderate otitis externa:

• Ear cleaning — your vet will thoroughly clean the ear, often under mild sedation
• Topical medication — drops or ointment containing a combination of antibiotic, antifungal, and anti-inflammatory. Applied daily for 7-14 days.
• Oral medications — for moderate infections, oral antibiotics or antifungals may be added. Oral anti-inflammatory medication (prednisone or Apoquel) helps reduce canal swelling.

For severe or chronic infections:

• Culture-guided antibiotic selection
• Extended treatment courses (3-6 weeks)
• Ear flush under sedation
• Investigation and treatment of underlying cause (usually allergies)

For otitis media/interna:

• Aggressive systemic antibiotics (4-6 weeks minimum)
• Pain management
• Anti-nausea medication if vestibular signs are present
• Possible surgery for non-responsive cases

Surgical options for end-stage ear disease:

• Total ear canal ablation (TECA) — removal of the entire ear canal. Reserved for dogs with irreversibly damaged ears that no longer respond to medical treatment. Eliminates chronic pain and infection. Most dogs do well and show improved quality of life despite hearing loss in the affected ear.

Prevention

Keep ears dry:

• Dry ears thoroughly after swimming or bathing
• Use a vet-recommended ear drying solution after water exposure
• Consider ear bands or covers for dogs that swim frequently
• Read our guide on bathing your dog for post-bath ear care tips

Regular cleaning:

• Clean ears weekly to biweekly with a vet-recommended cleanser
• Don't use cotton swabs deep in the canal — you'll push debris deeper
• Squirt cleaner into the canal, massage the base, and let your dog shake it out. Then wipe the visible portions with cotton balls.

Address underlying causes:

• If your dog gets more than 2 ear infections per year, investigate allergies
• Maintain flea prevention (flea allergies can affect ears)
• Consider allergy testing and management

Don't over-clean:

• Excessive cleaning can irritate the canal and disrupt natural flora
• If ears are healthy, cleaning every 1-2 weeks is sufficient

Routine monitoring:

• Check your dog's ears weekly — look for redness, smell, and discharge
• Lift floppy ears for air circulation during warm months

Check our dog breed guides for breed-specific ear care recommendations. When in doubt about what's going on in your dog's ears, a quick vet visit is always better than guessing.

FAQ

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

Over-the-counter ear cleaners can help prevent infections but cannot treat active infections. Prescription medication is almost always needed because the type of infection (yeast vs. bacteria) determines the treatment. Using the wrong product can worsen the infection.

How long does it take for an ear infection to clear up?

Most uncomplicated ear infections resolve within 7-14 days with proper treatment. Chronic or deep infections may take 4-6 weeks. Complete the full course of medication even if symptoms improve quickly — stopping early promotes resistant infections.

Why does my dog keep getting ear infections?

Recurrent ear infections (more than 2-3 per year) almost always indicate an underlying cause — most commonly allergies. Treating the ear infection without addressing the underlying allergy means the infections will keep returning. Ask your vet about allergy testing.

Should I pluck hair from my dog's ears?

This is debated. Some veterinary dermatologists recommend against routine ear plucking because it can cause inflammation and micro-trauma. Others recommend it for breeds with very dense ear canal hair. Ask your vet for breed-specific guidance.

Are ear infections painful for dogs?

Yes, ear infections can be quite painful. The ear canal is lined with sensitive tissue, and swelling creates pressure. Dogs may hide pain by becoming quieter or less playful. If your dog flinches or pulls away when you touch her ear, she's in pain and needs treatment.