Dog & Cat HospitalCalabasas

Patient Education

Ear Infections

Ear infections (otitis) are one of the most frequent reasons dogs and cats visit the vet — and one of the most undertreated, because the real cause is almost always hiding beneath the surface.

Otitis (ear infection) is inflammation and infection of the ear canal, caused by bacteria, yeast, or a combination of both. In dogs and cats, the ear canal forms an L-shape that traps moisture and debris, making it a hospitable environment for microorganisms to multiply. A single infection is usually straightforward to treat — but recurrent infections almost always signal an underlying issue like allergies, an anatomical abnormality, or a hormonal condition. At Dog & Cat Hospital Calabasas, we use in-house cytology (microscopic exam of ear debris) to identify exactly what organism is involved before prescribing treatment, so we target the real problem rather than guessing.

Signs & Symptoms

Ear infections can be subtle at first and worsen quickly if left untreated. Common signs include:

  • Head shaking or tilting the head to one side
  • Scratching at one or both ears with a paw or on furniture
  • Dark brown, yellowish, or blackish discharge from the ear canal
  • A yeasty or foul odor coming from the ear
  • Redness, swelling, or crustiness around the ear opening
  • Crying or pulling away when the ear is touched
  • Loss of balance, circling, or unusual eye movements (signs the infection has spread deeper)

Cats often show more subtle signs than dogs — persistent head shaking or a faint odor may be the only clue. Any of these warrant a same-day call.

Causes & Risk Factors

Ear infections are almost never "bad luck" — there is usually an underlying reason the canal became vulnerable. Common contributors include:

  • Environmental or food allergies (the single most common predisposing cause in dogs)
  • Excess moisture from swimming, bathing, or humid climates
  • Ear conformation — floppy, pendulous ears trap heat and restrict airflow (Cocker Spaniels, Basset Hounds, Golden Retrievers)
  • Excessive hair in the ear canal
  • Ear mites (especially in cats and young animals)
  • Foreign bodies such as grass awns
  • Hormonal imbalances like hypothyroidism that change skin and ear-canal health
  • Previous antibiotic courses that alter normal flora, allowing resistant organisms to take over

Scratching, shaking, or a smelly ear?

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How We Diagnose It

A thorough diagnosis goes beyond looking into the ear. Our approach at Dog & Cat Hospital Calabasas includes:

Otoscopic exam — We visualize the ear canal and eardrum (tympanic membrane) with a lighted scope. A ruptured eardrum changes treatment choices significantly.

In-house cytology — A gentle swab of the canal is stained and examined under the microscope within minutes. This tells us whether we're dealing with cocci bacteria, rod bacteria (often more resistant), yeast (Malassezia), or ear mites — and in what proportion. Choosing topical medication without cytology is guesswork.

Culture and sensitivity — Sent to an outside laboratory when cytology shows rod bacteria, when infections are chronic, or when initial treatment fails. Results guide which antibiotic will actually work.

Underlying-cause workup — For any pet with more than one infection per year, we discuss allergy testing, diet trials, thyroid screening, or other diagnostics to find the root cause.

Treatment Options

Treatment is tailored to what cytology and culture find:

Topical medications — Most routine infections respond to a veterinary ear drop containing an antibiotic and/or antifungal plus a corticosteroid to reduce inflammation. Completing the full course is critical; stopping early is a leading cause of recurrence.

Ear flush under sedation — Heavy debris, polyps, or a very painful ear often require professional cleaning before any medication can reach the canal wall. We perform thorough flushes in-house, often with the pet under light sedation for comfort.

Systemic medication — Severe or deep infections (otitis media — middle ear) may need oral antibiotics or antifungals in addition to topical treatment.

Long-acting in-canal treatments — For dogs with difficult-to-treat recurring infections or owners who struggle with daily drops, single-dose sustained-release formulations applied in the clinic are an option.

Surgery — Chronic, end-stage otitis that has destroyed the canal may benefit from a total ear canal ablation (TECA) with bulla osteotomy (removal of the diseased canal), performed by our surgical team.

When to See Our Calabasas Team

Don't wait for a "clearly infected" ear — early cytology visits prevent the mild infections that turn into resistant, painful, expensive ones. If your dog or cat has had more than one ear infection in a year, that pattern is a signal that something deeper needs to be addressed. Our team at Dog & Cat Hospital Calabasas can run cytology, culture, and an allergy workup in the same visit, so you leave with a plan rather than just another bottle of drops. Book an appointment to get to the bottom of your pet's ear issues.

Frequently Asked Questions

1Can I treat my dog's ear infection at home without seeing a vet?
Over-the-counter ear cleaners can help maintain a healthy ear, but they cannot treat an active infection. Using the wrong product — or any product — in an ear with a ruptured eardrum can cause permanent hearing damage, so a veterinary exam and cytology are needed before any treatment begins.
2Why does my dog keep getting ear infections over and over?
Recurrent ear infections almost always have an underlying cause, most commonly skin allergies (environmental or food). Treating only the infection clears the flare-up but leaves the root problem in place, guaranteeing the next one. A workup to identify and manage that underlying condition is the key to breaking the cycle.
3What happens if a dog's ear infection goes untreated?
Untreated otitis spreads from the outer canal inward to the middle ear (otitis media) and occasionally the inner ear (otitis interna), causing pain, balance problems, facial nerve damage, and in severe cases permanent hearing loss. Infections also become more resistant and harder to treat the longer they're left.
4Are ear infections contagious between dogs or between a dog and a cat?
Routine bacterial and yeast infections are not directly contagious between pets. Ear mites, however, spread easily between cats and can transfer from cats to dogs, so all pets in the household should be checked and treated if mites are found.
5How long does it take for a dog ear infection to clear up?
Mild infections often improve noticeably within a few days of starting the correct medication, but a full course typically runs 7 to 14 days. A recheck to confirm the infection is resolved — not just improved — is important, because stopping early is the most common reason infections return.
6My cat is shaking its head and one ear smells — is that always an infection?
Head shaking and an ear odor are classic infection signs, but ear mites, a foreign body, or a polyp can cause identical symptoms. A quick otoscopic exam and cytology smear tell us exactly what we're dealing with and point to the right treatment.
7Can ear infections cause my dog to lose hearing?
Yes, severe or chronically untreated infections can damage the eardrum and middle-ear structures, leading to partial or complete hearing loss. The risk is much higher when infections are allowed to recur without addressing the underlying cause.
8Is surgery ever needed for an ear infection?
Surgery is a last resort for end-stage chronic otitis where the ear canal has become so scarred, calcified, and diseased that it no longer functions — medication can no longer penetrate it effectively. A total ear canal ablation (TECA) removes the diseased tissue and provides lasting relief in those cases.
9Should I clean my dog's ears at home to prevent infections?
Regular ear cleaning with a veterinarian-recommended cleanser helps remove debris and moisture that promote infection, and is especially important for dogs that swim or have floppy ears. Cleaning technique matters — we're happy to demonstrate the right approach at your next visit.

Related

ProceduresTotal Ear Canal Ablation (TECA)ProceduresVentral Bulla Osteotomy

Scratching, shaking, or a smelly ear?

Our team performs same-visit cytology to identify exactly what's causing your pet's ear problem — and build a plan that targets the root cause, not just the flare-up.

Book an Appointment