Oídos y audición

The ear does two jobs at once: it captures sound, and its inner portion helps the brain track the body's position in space. That second job means ear disease can cause problems that have nothing to do with hearing at all, including a stumbling gait or a head tilt that looks more like a neurological problem than an ear one.

Dogs, particularly breeds with floppy or heavily furred ears, develop ear disease more often than almost any other companion species, since reduced airflow into the canal creates a warm, moist environment that favors yeast and bacteria. Cats and rabbits are more prone to ear mites, tiny parasites that live in the canal and cause intense itching.

Birds lack the external, funnel-shaped pinna seen in mammals, hearing instead through a small feathered opening on the side of the head, which changes how ear disease looks and how it is examined. Fish have no external ear at all, sensing vibration and orientation through internal structures and a separate sensory system along their body called the lateral line.

The outer ear includes the pinna, the visible flap that funnels sound inward, and the ear canal leading to the eardrum. In dogs and cats, this canal bends sharply from vertical to horizontal before reaching the eardrum, a shape that traps debris and moisture more easily than the straighter canal seen in many other species.

Behind the eardrum sits the middle ear, a small air-filled space containing tiny bones that transmit vibration inward, connected to the throat by the eustachian tube, which helps equalize pressure. The inner ear houses the cochlea, which turns vibration into the nerve signals the brain reads as sound, and the vestibular apparatus, a set of fluid-filled canals that track head position and movement.

Ear shape varies widely by species and even by breed. Upright ears, seen in many cat breeds and some dogs, allow better airflow and generally lower infection rates than the floppy, low-hanging ears bred into many dog breeds. Rabbits have particularly long ear canals that make thorough examination and cleaning more difficult than in a cat. Reptiles have no external ear structure at all, sensing sound largely through vibration conducted via the jaw and skull.

Otitis externa, inflammation of the outer ear canal, is by far the most common ear problem in dogs, often driven by allergies, excess moisture, or an underlying yeast or bacterial overgrowth rather than a single simple cause. Left untreated, it can progress into the middle ear, becoming otitis media, or further into otitis interna affecting balance and hearing.

Ear mites are a frequent cause of intense ear itching in cats, rabbits, and young puppies, producing a distinctive dark, crumbly discharge. Aural hematoma, a pooling of blood within the ear flap, usually follows vigorous head shaking or scratching that ruptures a small blood vessel, often itself triggered by an underlying infection or irritation.

Deafness can be congenital, more common in white-coated dogs and cats with blue eyes due to a shared genetic pathway, or acquired later in life from chronic infection, age-related nerve changes, or in rare cases certain medications. Cats can also develop inflammatory polyps that grow within the ear canal or middle ear, causing symptoms that mimic a chronic infection until the growth itself is found and removed.

Frequent head shaking or scratching at one or both ears is usually the first sign an owner notices, often before any odor or discharge becomes obvious. A sour or yeasty smell, or a dark, waxy, or crumbly discharge, points toward infection or mites depending on its appearance and consistency.

A swollen, fluid-filled pocket within the ear flap that appears after a bout of scratching is a hematoma and will not resolve without treatment. Pain on touching the base of the ear, or a pet that flinches or resists having its ears handled, suggests the problem is more advanced than surface irritation.

Balance-related signs, a head tilt, stumbling, circling toward one side, or rapid, flicking eye movements, point toward the inner ear rather than the outer canal, and can look alarmingly similar to a brain problem. Reduced response to sound, whether missed cues to come when called or sleeping through noises that used to wake a pet, can signal developing hearing loss.

Seek prompt same-day or emergency care for a sudden head tilt combined with stumbling, circling, or rapid eye flicking, since this pattern can reflect inner ear or even brain involvement that benefits from quick diagnosis. Severe pain, marked swelling of the ear flap, or a pet that will not tolerate any touch near the ear also warrants a same-day look.

A same-day to short-notice visit fits ongoing head shaking with visible discharge or odor, since untreated outer ear infections can progress into the middle ear within days and become harder to resolve. A newly noticed hematoma is not usually a true emergency but is easiest to treat well before it has fully organized.

A routine visit is reasonable for mild, occasional scratching without discharge, or a gradual decline in a pet's response to sound, particularly in an older animal where some hearing loss is expected. Even gradual hearing loss is worth confirming, since ruling out a treatable cause is straightforward at a routine visit.

Why do dogs with floppy ears get more infections?

Floppy ears reduce airflow into the canal, keeping it warmer and more humid than an upright ear, which favors the yeast and bacteria that cause most outer ear infections.

Are ear mites contagious to other pets?

Yes, ear mites spread easily between animals in close contact, so other pets in the household are often treated at the same time even if they show no symptoms yet.

Does a head tilt always mean a brain problem?

Not usually. A head tilt more often comes from inner ear disease than from the brain, though a vet exam is needed to tell the two apart with confidence.

Can hearing loss in older pets be treated?

Age-related hearing loss from nerve changes generally cannot be reversed, but any contributing wax buildup or infection can be treated, and many pets adjust well using visual and scent cues instead.

Is an ear hematoma an emergency?

It is uncomfortable but rarely dangerous in the short term. Treatment is still worthwhile fairly soon, since an untreated hematoma can heal in a way that permanently wrinkles the ear.