Ear infections, and why they keep coming back
4 min read · Updated
Ear infections turn up in profile after profile here — the spaniels, the retrievers, the swimming breeds, anything with a heavy drop ear. What most of those entries cannot fit is the single most useful fact about them: an ear that keeps getting infected usually has an underlying cause that has nothing to do with ears, and treating the ear alone is why it keeps coming back.
The shape of the problem
A dog's ear canal is not a tube from the outside to the eardrum. It runs down and then turns inward, roughly an L, with the eardrum at the far end of the horizontal part.
That shape means anything that gets into it — water, debris, discharge — does not simply run back out, and it means the bottom of the canal stays warm and damp. Heavy drop ears close the opening over the top of that, and a hairy canal holds moisture in place.
So the breeds that suffer are predictable: cocker and springer spaniels, basset hounds, coonhounds, poodles and doodles with hair growing in the canal, retrievers and other dogs that swim, and shar-peis, whose canals are unusually narrow to begin with.
Why it keeps coming back
This is the part worth knowing before spending another year on drops.
Yeast and bacteria are what a swab finds, and they are usually not the reason. They are opportunists growing in an ear that has already become inflamed, and the commonest thing that inflames it is allergy — environmental allergy or food allergy — which changes the skin lining the canal and turns it into somewhere they can live.
So a dog with recurring ear infections very often has undiagnosed allergic skin disease, and the ears are simply the first place it shows. Ear mites, a foreign body such as a grass seed, a polyp, or an underactive thyroid are the other causes worth ruling out.
Treating each infection and stopping there means treating the symptom every few months indefinitely. If it comes back more than twice, the question to ask a vet is what is causing it, not what to put in it.
What not to do
No cotton buds. The canal turns a corner, so a bud pushes debris around that corner and packs it against the eardrum, which is worse than what you started with.
Do not medicate an ear without knowing the eardrum is intact. Several common ear preparations can damage hearing or balance if they reach the middle ear through a perforation, which is exactly why a vet looks before prescribing, and why last year's leftover bottle is not a safe thing to reach for.
Skip the home remedies. Vinegar, hydrogen peroxide and surgical spirit on an inflamed canal hurt, and alcohol on broken skin is genuinely cruel.
Do not clean healthy ears routinely unless a vet has said to. Over-cleaning strips a canal that is managing perfectly well and creates the irritation it was meant to prevent.
What actually helps
Look and smell rather than poke. A healthy ear is pale, dry and does not smell. Yeast has a distinctly sweet, musty odour that owners learn to recognise across a room.
Dry the ears after swimming or a bath, gently, with cotton wool at the opening and no deeper.
Keep hair in the canal trimmed if the breed grows it. Plucking is contested — for some dogs it helps, for others it inflames the canal — so it is worth asking a vet what suits the individual rather than following a blanket rule.
Use a proper ear cleaner if one has been recommended: fill the canal, massage the base of the ear until it squelches, then let the dog shake, and wipe what comes up. Wiping the outside without filling the canal cleans the part that was not the problem.
And take head shaking seriously. A dog shaking its head hard and repeatedly can burst a blood vessel in the ear flap, which swells into a haematoma and often needs surgery — a second problem caused entirely by the first going untreated.
Cats, rabbits and the rest
In cats, especially kittens and rescues, ear mites are far more likely than in dogs — dark crumbly discharge like coffee grounds, and intense scratching. They are treatable and they are contagious to other pets in the house.
Lop-eared rabbits have a structural version of the same problem: the fold that gives them their ears narrows the canal, wax builds up behind it, and infection follows. It is one of the routine costs of the lop breeds and worth knowing before choosing one.
Any animal holding its head tilted to one side, losing balance, or with flicking eye movements has something affecting the middle or inner ear, and that is a same-day veterinary problem rather than an ear-cleaning one.