Dog Ear Infection: Symptoms, Causes, Treatment & Prevention 2026
Dog ear infections — medically called otitis — are one of the top reasons pet owners visit the vet, affecting roughly 20% of dogs. They range from mildly itchy to intensely painful if left untreated. Understanding the causes, recognising symptoms early, and knowing when to see a vet can save your dog significant suffering.
What Is a Dog Ear Infection?
A dog ear infection is an inflammation of the ear canal, classified as otitis externa (outer ear — most common), otitis media (middle ear), or otitis interna (inner ear). Most infections involve overgrowth of yeast (Malassezia) or bacteria (Staphylococcus, Pseudomonas).
Dogs with floppy ears — Cocker Spaniels, Basset Hounds, Labradors, Poodles — are most predisposed because the ear flap traps heat and moisture. Dogs who swim frequently or have allergies are also at higher risk.
Signs and Symptoms of Dog Ear Infection
- Head shaking or tilting to one side
- Scratching at the ear or rubbing it on furniture
- Redness, swelling, or warmth inside the ear
- Dark, waxy, or coffee-ground-like discharge
- Foul or yeasty odour from the ear
- Pain when the ear is touched
- Loss of balance or stumbling (severe inner ear cases)
- Hearing loss (chronic cases)
Yeast infections produce brownish discharge with a musty smell. Bacterial infections produce a pungent odour; discharge may be yellow, green, or bloody. In puppies, ear infections can resemble ear mites — your vet can distinguish between them under a microscope.
Causes of Dog Ear Infections
- Allergies — the number one trigger for chronic ear infections; immune inflammation allows yeast and bacteria to overgrow
- Moisture — water trapped after swimming or bathing creates a breeding ground
- Foreign bodies — grass seeds, dirt, or debris in the ear canal
- Ear mites — common in puppies; parasites trigger secondary infections
- Hormonal imbalances — hypothyroidism and Cushing’s disease affect ear health
- Narrow or hairy ear canals — structural predisposition in certain breeds
Identifying and treating the underlying cause is essential for preventing recurrence. Without treating the trigger — especially allergies — most ear infections return within weeks to months.
Diagnosis and Treatment
Your vet will perform an otoscopic examination and take a cytology swab to identify yeast or bacteria under a microscope. Chronic or severe cases may need a culture and sensitivity test to find the most effective antibiotic. Treatment options include: topical ear drops (antifungal, antibiotic, and anti-inflammatory combination); oral medications for deep infections; one-time in-clinic treatments such as Claro or Osurnia (lasting 30 days); and, rarely, Total Ear Canal Ablation (TECA) surgery for end-stage disease.
Prevention Tips
- Dry ears thoroughly after swimming or bathing
- Clean ears weekly with a vet-approved cleaner — never over-clean
- Manage underlying allergies through food trials, antihistamines, or immunotherapy
- Keep ear hair trimmed in hairy-eared breeds
- Schedule routine vet checks to catch early changes before they become infections