If a Lab’s ear infections keep coming back — cleared by the vet, then back again within weeks or months — the treatment is working on the symptom, not the cause. Recurring infections almost always mean there’s an underlying driver that hasn’t been found yet, and chasing the infection itself round after round rarely fixes that.
Allergies are the usual culprit
VCA Animal Hospitals puts allergies behind roughly 43% of all dog ear infection cases, and the link is even stronger with food allergy specifically — 65 to 80% of dogs with a genuine food allergy end up with ear infections as one of the symptoms. Allergic inflammation changes the ear canal environment (more moisture, a disrupted microbial balance) in a way that lets bacteria and yeast overgrow. Clearing the infection without addressing that inflammation just resets the clock until it happens again.
Two allergy types tend to be behind it. Environmental allergy (atopy) reacts to things like dust mites, pollen, or mould, is often seasonal, and Labs with it usually have other itchy spots too — paws, belly, face. Food allergy reacts to a specific protein, runs year-round rather than seasonally, and can only really be confirmed with a strict elimination trial: 8 to 12 weeks on a genuinely novel protein or a hydrolysed diet, with nothing else sneaking in. Cornell’s veterinary dermatology team is blunt about this pattern too — allergic inflammation is usually the first thing they look for whenever a dog keeps scratching at its ears, with infection following as a secondary problem.
The other three usual suspects
Allergy isn’t the only explanation, though it’s the most common one by a wide margin.
- Ear anatomy. A Lab’s long, floppy ear flap cuts down airflow into the canal, and the canal itself angles downward before turning toward the eardrum — a shape that’s good at holding onto moisture. This predisposes Labs regardless of allergy status, which is why dogs who swim a lot need after-swim ear care as a standing routine rather than something they only think about once an infection’s already started.
- Foreign bodies. Grass seeds, especially in summer, are a classic cause of a sudden, often severe infection in a dog that’s been in long grass. They don’t work themselves out — they need a vet to remove them.
- Incomplete treatment. An infection that looks better but wasn’t fully cleared — usually because the course was cut short or the recheck got skipped — comes back, sometimes with a population that’s a little more resistant to whatever was used the first time.
- Hormonal conditions. Less common, but worth ruling out: hypothyroidism in particular can drive repeated ear infections and is easy to miss if nobody’s specifically testing for it.
What a real investigation looks like
Two or more infections in a year is the point to ask your vet for something beyond another round of drops. A proper work-up usually includes cytology (a microscope look at the discharge to identify bacteria, yeast, or both), culture and sensitivity testing if bacteria show up, a full skin and allergy assessment if there’s itching elsewhere on the body, and a food elimination trial if environmental allergy testing comes back negative or unclear. For anything that isn’t resolving with this, a referral to a veterinary dermatologist brings tools and experience general practice usually doesn’t have on hand.
Worth knowing: VCA also flags that a severely chronic, untreated infection can cause the ear canal to swell shut (stenosis), at which point medication can’t reach where it needs to go and surgery — most often a lateral ear resection — becomes the only real option. That’s a strong argument for investigating properly the second or third time round, not the fifth.
Keeping a prone Lab out of the cycle
- Ear-drying solution after every swim, not just the occasional one
- Monthly cleaning with a vet-approved cleaner, kept up even when the ears look fine
- Drying the ear flaps properly after bathing
- Managing an underlying allergy under vet guidance — antihistamines, Apoquel, Cytopoint, or immunotherapy for atopic dogs
- A proper elimination diet trial if food allergy is on the table, rather than just switching to a different bag of food and hoping
If your Lab’s had four infections this year, that’s not something to just accept as part of owning a floppy-eared dog — it means the underlying cause hasn’t been pinned down or managed yet, and it’s worth pushing for a dermatology referral rather than a sixth prescription. A vet visit that actually finds the allergy or removes the grass seed is the one that breaks the cycle. Repeat ear drops on their own generally aren’t.
For general symptoms and home care once you’re mid-infection, my guide to ear infection signs and safe home care covers that side. Swimming is one of the biggest recurring triggers for Labs specifically — see skin problems after swimming for more on that. And since recurring infections get more common with age, it’s worth building regular ear checks into a senior Labrador’s routine care.