Cat Ear Infections and Ear Mites: Signs, Common Causes and Why a Vet Check Matters
Ear mites are a classic cause of itchy cat ears, but they are not the only one. Here is how to spot ear trouble, what usually causes it, and what you can safely do at home while you wait for the vet.
Cats with ear mites or an ear infection usually shake their heads, scratch at their ears and have dark, smelly or excessive discharge. Mites are common, especially in kittens and outdoor cats, but yeast, bacteria, allergies, foreign bodies and growths called polyps can look much the same. Because the treatment depends on the cause, and some causes can damage the eardrum, any ear problem in a cat needs a veterinary exam before you treat it.
This guide explains what to look for and what is going on. It does not replace a diagnosis: if your cat’s ears look or smell abnormal, contact your veterinarian.
Signs of ear trouble in cats
- Frequent head shaking or tilting the head to one side
- Scratching at the ears, sometimes leaving scabs or wounds around the ears and face
- Dark brown or black, crumbly or waxy debris in the ear canal
- Yellow or pus-like discharge, or a bad smell
- Red, swollen or scaly skin inside the ear flap
- Holding the ears flat, or flinching when the head is touched
- A swollen, puffy ear flap (often a blood blister from shaking, called an aural hematoma)
The Merck Veterinary Manual describes inflammation of the outer ear canal (otitis externa) as the most common ear canal disorder in cats, with signs such as head shaking, odor, redness, swelling, scratching and discharge, in one or both ears.
Common causes
| Cause | What it is | Typical clues (not a diagnosis) |
|---|---|---|
| Ear mites (Otodectes cynotis) | Tiny parasites living in the ear canal; very contagious through close contact | Intense itch, dark crumbly debris, often both ears; common in kittens, outdoor cats and multi-pet homes |
| Yeast (usually Malassezia) | Yeast that lives in small numbers in normal ears and overgrows when the ear is inflamed | Brown, waxy discharge and odor; often secondary to another problem |
| Bacteria | Bacterial overgrowth in an inflamed canal | Yellow or pus-like discharge, pain, odor |
| Allergies | Food or environmental allergies that inflame the skin, including the ear canal | Recurring ear problems plus itchy skin elsewhere, such as the face, neck or belly |
| Inflammatory polyps | Benign growths, usually in young cats, that start in the middle ear or the back of the throat | One-sided, persistent discharge; head tilt or loss of balance; sometimes sneezing or noisy breathing |
| Foreign bodies | Grass seeds, plant awns or debris lodged in the canal | Sudden, often one-sided head shaking after time outdoors |
In cats, an ear infection is often a secondary problem. Mites, allergies, a polyp or a foreign body inflame the canal first, and yeast or bacteria take advantage. That is why simply treating the infection may not stop it coming back: the underlying trigger has to be found, too.
A closer look at ear mites
Ear mites are about the size of a pinhead and spread easily between cats, and between cats and dogs, through close contact. According to the Cornell Feline Health Center, infested ears typically contain dark, foul-smelling wax and debris, and untreated mites can lead to injury from scratching, secondary infection and inflammation that may spread deeper into the ear, affecting the eardrum, hearing and balance.
If one pet in your home has mites, ask your vet whether the other cats and dogs should be checked or treated at the same time. Treating only one animal can allow mites to bounce back.
Polyps: the cause owners rarely think of
Inflammatory (nasopharyngeal) polyps are benign growths most often found in young cats. They can grow into the ear canal and cause chronic infection, or affect the middle ear and cause a head tilt, unsteady walking or unusual eye movements. They are diagnosed by a vet, usually under sedation and sometimes with imaging, and are generally treated by removal. No ear drop will make a polyp go away.
Why a vet diagnosis matters
Dark debris looks similar whether it comes from mites or yeast, and the products that treat one may do nothing for the other. A vet will usually:
- Look into the ear canal with an otoscope to check for mites, foreign bodies, growths and the state of the eardrum.
- Take a swab of debris and look at it under a microscope (cytology) to identify mites, yeast or bacteria.
- Ask about itching elsewhere, diet and other pets, to look for an underlying cause such as allergies.
- Recommend treatment based on what is found, and often a recheck to confirm it has cleared.
Checking the eardrum is especially important. Some ear products can be harmful if the eardrum is damaged, which you cannot see at home. Over-the-counter ear products bought without a diagnosis can delay proper treatment, and products meant for dogs are not always safe for cats.
Safe ear care at home
Healthy cat ears usually need little or no cleaning. If your vet recommends cleaning, they will show you how and suggest a cleaner suitable for your cat. General safe-handling basics:
- Only use products your vet recommends. Avoid hydrogen peroxide, alcohol, vinegar, essential oils and household remedies, which can irritate an already inflamed canal.
- Never push cotton swabs into the ear canal. They can pack debris deeper and injure the canal. If you are wiping, use a soft cotton pad or gauze on the visible parts of the ear flap only.
- Be gentle and stop if your cat is in pain. A painful ear is a reason to see the vet, not to keep cleaning.
- Finish the full course of any treatment your vet prescribes, even if your cat seems better, and go back for rechecks.
- Look regularly. A quick weekly peek during cuddles helps you spot changes early. Our guide on signs your cat is in pain explains other subtle clues.
Keeping up with year-round parasite prevention recommended by your vet can also help, since some products cover ear mites; see our flea and tick prevention guide.
See a vet promptly if you notice
- A head tilt, loss of balance, walking in circles or unusual eye movements
- Pain when the head or ears are touched, or your cat stops eating
- Bleeding, pus or a strong smell from the ear
- A swollen ear flap
- Facial drooping or a drooping eyelid on one side
- Ear problems in a young kitten, or ear trouble that keeps coming back
Balance problems or sudden severe signs are a reason to call your vet the same day or contact an emergency clinic.
Bottom line
Head shaking, scratching and dark debris are classic signs of cat ear trouble, but mites, yeast, bacteria, allergies, polyps and foreign bodies can all look alike. Let your vet look inside the ear and examine a swab before anything goes in it, follow the treatment plan fully, and ask whether other pets need checking too.
FAQ
Can I tell ear mites from an ear infection at home?
Not reliably. Both can cause dark discharge and itching, and they often occur together. A vet can confirm mites with an otoscope or by looking at a swab under a microscope.
Can indoor cats get ear mites?
Yes, though it is less common. Mites spread through close contact, so a new kitten, a visiting pet or a dog that goes outdoors can bring them in.
Can people catch ear mites from cats?
Ear mites mainly affect cats, dogs and some other pets. Human problems are considered rare; if you develop an itchy rash, speak to your own doctor.
Why do my cat’s ear infections keep coming back?
Recurring infections often point to an underlying cause, such as allergies or a polyp, that has not been addressed. Ask your vet about investigating further.
