DOGS · Condition guide
Otitis externa in dogs: real veterinary cases
Otitis externa — inflammation of the outer ear canal — is the second-most-common diagnosis in UK primary care (7.3% of all dogs in a given year). Most owners think of it as a one-off infection. In reality, it's almost always a downstream sign of something else: underlying allergy (atopic dermatitis, food allergy), ear conformation (floppy ears, hairy canals), or moisture trapped after swimming.
Cytology is the single most useful test — a tape strip and a quick look under the microscope tells the vet whether they're dealing with yeast (Malassezia), cocci, rods (often Pseudomonas, which can be hard to treat), or mixed populations. Treating without cytology is the most common reason ear infections "keep coming back". For chronic or relapsing cases, identifying and managing the underlying allergy is what actually breaks the cycle.
What vets typically check for
- Otoscopic exam — check for foreign bodies (grass awns), polyps, ruptured tympanic membrane.
- Cytology of ear discharge — yeast vs. bacteria; rods raise concern for Pseudomonas.
- Culture + sensitivity if rods are seen or repeat infections aren't responding.
- Treat the infection AND investigate underlying allergy if the dog has recurrent disease.
- Severe end-stage cases: video otoscopy, CT imaging, total ear canal ablation (TECA) as a last resort.
Not a replacement for veterinary care. Use this to walk into the conversation prepared, not to self-diagnose.
Real cases from the veterinary literature
Peer-reviewed reports our semantic search surfaces for Ear infection in dogs (otitis externa). Click into any case for the full abstract — or run a personalised search with your pet's exact details.
- Malassezia pachydermatis isolated from normal and diseased external ear canals in dogs: a comparative analysis.
Veterinary journal (London, England : 1997) · 2006 · Brazil
This study looked at a type of yeast called Malassezia pachydermatis to see if it causes ear infections in dogs. Researchers collected samples from the ears of dogs with ear infections and from healthy dogs. They found that 63.7% of the dogs with ear infections had signs of this yeast, while only 21.43% of healthy dogs with one infected ear showed it. Most of the dogs with the
- Malassezia otitis unresponsive to primary care: outcome in 59 dogs.
Veterinary dermatology · 2021 · United Kingdom
This study looked at 59 dogs with a persistent ear infection caused by a type of yeast called Malassezia, which often doesn't get better with regular vet care. The researchers found that a special ear cleaning treatment worked well, resolving the infection in 91% of the cases, usually within about 27 days. They also noted that about 17% of the dogs had a related middle ear infe
- Reproducibility of ear cytology in dogs with otitis externa.
The Veterinary record · 2010 · Germany
In a study involving 83 dogs showing signs of ear infections (otitis externa), researchers looked at samples taken from both ears to check for germs. They found that certain breeds, like golden retrievers and West Highland white terriers, were more likely to develop these ear infections, especially in dogs with floppy ears compared to those with upright ears. The study showed t
Frequently asked questions
- Why do the infections keep coming back?
- Almost always because the underlying cause hasn't been addressed. The most common driver is allergy — atopic dermatitis or food allergy. Until the allergy is managed, the ear environment stays primed for repeat infections. Discuss allergy testing or a strict food trial with your vet if your dog has had ≥3 ear infections in a year.
- Are home remedies safe?
- No. Over-the-counter ear cleaners are fine for routine cleaning, but if there's any infection the eardrum status must be confirmed first — many topical antibiotics are damaging to the inner ear if the eardrum is ruptured. Vinegar, hydrogen peroxide, and other home solutions can worsen inflammation and irritate damaged tissue.
- What if it's Pseudomonas?
- Pseudomonas otitis is one of the toughest infections in small-animal practice — it forms biofilms and develops resistance quickly. Treatment usually requires culture-guided antibiotics, aggressive ear flushing (often under sedation), and prolonged therapy. Refer to a dermatologist or specialist if your dog has confirmed Pseudomonas.