Dog & cat health · Vet-reviewed guide

Cat Ear Infection: Signs and Causes

A cat pawing at its ear and shaking its head isn't just annoyed — something's usually wrong in there. The tricky part is that ear problems in cats have several very different causes.

Quick answer: A cat ear infection causes head shaking, ear scratching, discharge, odor, and pain — and unlike ear mites, it often develops secondary to another problem. Cats get ear infections less often than dogs, so when one occurs a vet looks for an underlying cause: ear mites, allergies, a polyp or foreign object, or excess wax that let bacteria or yeast overgrow.

If a vet prescribes an antibiotic: our licensed veterinarian can review your pet and, when appropriate, provide cephalexin for dogs & cats — the prescription is included at no separate cost, and you pay only for the medication.

The treatment depends on what is actually growing, because a bacterial infection and a yeast infection need different medicines, and only a vet examining a swab under the microscope can tell them apart reliably. That is also why guessing with over-the-counter drops often fails, and why an untreated ear infection can damage the eardrum, which changes what is safe to put in the ear. This guide covers the signs, why the cause matters, and when your cat needs a vet.

Signs of an ear infection

• Head shaking and tilting
• Scratching or pawing at the ear
• Yellow, brown, or black discharge
• Redness, swelling, and a bad smell
• Pain when the ear is touched, and sometimes balance problems²

Why it's often secondary

Because ear infections are less common in cats than dogs, a vet treats a cat ear infection as a signal to find what let it happen: most often ear mites, allergies, a growth or polyp in the ear, a foreign object, or heavy wax.¹ Treating the infection without the underlying cause tends to let it come back.

Yeast versus bacteria — why the vet swab matters

An ear infection can be bacterial, yeast, or both, and each needs different medication.² The reliable way to know is a vet looking at a swab under the microscope, which also lets the vet check whether the eardrum is intact — important, because a ruptured eardrum changes what medicine is safe to use. Reaching for over-the-counter drops on a guess can treat the wrong thing and let the infection worsen.

When to see a vet

See a vet for any suspected ear infection, and promptly if there is a head tilt, loss of balance, severe pain, or bleeding, which can signal a deeper, middle-ear problem.² A vet identifies the cause, cleans the ear, and prescribes the right medicine. Any prescribed medicine must come from a vet. See how our vet prescription service works. If the cause turns out to be mites, see our ear mites guide.