Ear infections (otitis externa) are among the top five reasons dogs visit veterinary clinics each year. The canine ear canal is shaped differently from a human's — it has a long vertical component that angles into a horizontal component before reaching the eardrum. This L-shaped architecture creates a warm, moist environment where bacteria and yeast can thrive.

Understanding why ear infections happen, how to recognize them early, and how to clean and medicate ears correctly can save your dog considerable discomfort — and save you significant veterinary costs over time.

Why Dogs Get Ear Infections

Ear infections rarely occur in isolation. Most are secondary to an underlying problem that creates the conditions for microbial overgrowth. The most important underlying causes are:

• Allergies: Environmental allergies (atopy) and food allergies are the single most common underlying cause of recurrent ear infections in dogs. Allergic inflammation changes the microenvironment of the ear canal, promoting yeast and bacterial growth. If your dog gets ear infections more than twice a year, allergy evaluation is essential.
• Conformation: Dogs with pendulous (floppy) ears — Cocker Spaniels, Basset Hounds, Golden Retrievers — have reduced air circulation in the ear canal. Dogs with excessive hair in the ear canal (Poodles, Schnauzers) face the same issue.
• Moisture: Swimming, bathing, or even humid environments can tip the balance toward infection. Water softens the skin lining the ear canal and allows microorganisms to penetrate.
• Hormonal disorders: Hypothyroidism and Cushing's disease alter skin health and immune function, increasing susceptibility.
• Foreign bodies: Grass awns (foxtails) are notorious for burrowing into ear canals, particularly in working and sporting breeds.
• Ear mites: More common in young dogs and cats; cause intense itching and a distinctive dark, crumbly "coffee ground" discharge.

Recognizing an Ear Infection

Early recognition allows treatment before the infection spreads deeper (otitis media — middle ear infection) or causes chronic changes to the ear canal. Signs include:

• Head shaking or tilting
• Scratching at one or both ears
• Redness or swelling inside the ear flap or at the canal opening
• Discharge — yellow or brown discharge suggests bacterial infection; dark brown or black discharge with a yeasty smell suggests yeast overgrowth
• Odor from the ear
• Pain when the ear is touched (dogs may pull away or vocalize)
• In severe cases: hearing loss, balance problems, or head tilt suggesting middle or inner ear involvement

According to the AVMA, prompt veterinary treatment of ear infections is important — delayed treatment allows infection to extend deeper into the canal and can lead to chronic, painful changes including stenosis (narrowing) of the ear canal that may ultimately require surgery.

Veterinary Diagnosis and Treatment

Your vet will examine the ear canal with an otoscope and take an ear cytology — a simple, in-office test where a swab sample from the ear is examined under the microscope. This critical step identifies whether the infection is bacterial (rods or cocci), yeast (Malassezia), or a mixed infection, and determines what treatment is appropriate. Treating a yeast infection with antibiotics — or vice versa — is ineffective and allows the wrong organism to proliferate.

Treatment typically involves:

• Professional ear cleaning in the clinic, which reaches areas home cleaning cannot
• Prescription ear drops containing combinations of antibiotics, antifungals, and corticosteroids (to reduce inflammation and swelling)
• Systemic antibiotics or antifungals for severe or deep infections
• Treatment of the underlying cause (allergy management, thyroid treatment, etc.)

For dogs who resist frequent ear drop applications, long-acting single-application products (such as Claro or Osurnia) can be applied by the vet and provide treatment for up to 30 days — a significant advantage for difficult dogs.

How to Clean Your Dog's Ears at Home

Routine ear cleaning is appropriate for dogs prone to ear problems, after swimming, or as part of regular grooming. For dogs with healthy ears, cleaning every 1–4 weeks is typical — over-cleaning can irritate the ear canal and disrupt its natural microbiome.

Step-by-step cleaning process:

1. Gather supplies: a veterinarian-recommended ear cleaner (look for drying agents like isopropyl alcohol or salicylic acid — avoid products with alcohol in dogs with inflamed ears, as they sting), cotton balls or gauze squares. Never use cotton swabs (Q-tips) — they push debris deeper and risk eardrum injury.
2. Lift the ear flap and fill the ear canal generously with cleaner.
3. Massage the base of the ear for 20–30 seconds — you should hear a squishing sound as the solution moves through the canal.
4. Let your dog shake their head — this brings loosened material up to the surface.
5. Use cotton balls to wipe out debris from the visible part of the ear canal and the ear flap. Only clean as deep as you can comfortably see.
6. Repeat if needed until the cotton comes away relatively clean.

The AKC provides a helpful visual guide to ear cleaning that many first-time owners find useful.

Preventing Ear Infections

Prevention focuses on addressing the underlying risk factors:

• Post-swim drying: After any swimming or bathing, place a few drops of a drying ear cleaner in each ear and massage. Alternatively, gently wick moisture from the ear with a cotton ball.
• Allergy management: If your dog has recurrent infections, work with your vet to identify and manage the underlying allergy — whether through dietary elimination trials, environmental controls, or immunotherapy.
• Routine maintenance cleaning: For high-risk breeds, weekly cleaning significantly reduces infection frequency.
• Ear hair management: In dogs with excessively hairy ear canals, regular plucking or trimming by a groomer improves airflow. (Note: the evidence on whether ear hair removal helps or harms is mixed — discuss with your vet.)
• Prompt treatment of any early signs: A small infection caught early is far easier — and cheaper — to treat than a chronic, refractory infection.

When to See the Vet

See your vet if your dog is shaking their head or scratching their ear more than a couple of times daily, if you notice any discharge or odor from the ear, if the ear looks red or swollen, or if your dog shows pain when the ear is touched. Seek urgent care if you notice a sudden head tilt, loss of balance, or walking in circles — these signs suggest middle or inner ear involvement, which is a more serious and complex condition requiring immediate evaluation.