When to see a vet urgently
Seek prompt treatment if ear symptoms are accompanied by any of the following:
- Loss of balance, falling over or inability to walk.
- Involuntary eye movements or a new marked head tilt.
- Changes in facial movement or inability to close an eye.
- Severe pain, refusal to eat or a sudden decline in general health.
These signs may indicate a problem extending beyond ordinary otitis externa. You can find a vet near you.
Overview
A cat's external ear canal is lined by sensitive, gland-containing skin with hairs on its surface. Irritants or infection cause inflammation, discomfort, pain and reduced hearing. Otitis externa can affect one or both ears and be acute or chronic.
You may first notice the characteristic smell, discharge and constant scratching around the head.
Otitis externa means inflammation of the canal skin; not every case is simply a bacterial infection. Mites or allergy, for example, may initiate inflammation, with bacteria or yeasts multiplying secondarily in the altered ear. If only microbes are treated while the original cause remains, symptoms may recur.
Causes
The main causes of otitis externa in cats include:
- Parasites: the ear mite Otodectes cynotis is one of the most common causes.
- Bacterial infections, including staphylococci and streptococci.
- Fungal infections, including Malassezia.
- Foreign objects in the ear, such as debris or grass seeds.
- Allergies, including food allergy or atopic dermatitis.
- Ear injuries.
- Ear canal tumours, more often in older cats.
Malassezia is a yeast that can also occur in small numbers in a healthy cat's ear. Some bacteria likewise form part of the normal ear microbiota. Finding a microbe alone therefore does not establish an infection needing treatment: the sample is interpreted alongside inflammatory cells, microbial numbers and symptoms.
Recurrent or persistently one-sided symptoms also prompt a search for a structural cause. An inflammatory polyp can extend from the middle ear into the canal and sustain inflammation. A polyp differs from a malignant tumour, but appearance is not always enough to identify a tissue lesion.
Risk factors
- Kittens and young cats, which more often acquire ear mites.
- Cats with outdoor access.
- Cats with allergies or chronic skin inflammation.
- Breeds with narrow canals or abundant ear hair, such as Persians and Exotic Shorthairs.
There is limited information on precisely defined breed-related risks in cats. Breed, hairiness or outdoor access alone does not establish the cause, and an indoor cat can also become ill. Contact with other animals also affects mite exposure; nevertheless, a young cat's itching is not always caused by mites.
Typical symptoms
- Head shaking and tilting towards the painful ear.
- Scratching the ears with the paws.
- Brown, purulent or clear discharge.
- An unpleasant ear smell.
- Redness and swelling of the canal.
- Tenderness to touch.
- In severe cases, hearing loss and pain-related aggression.
A head tilt should not automatically be interpreted as pain alone. If accompanied by poor balance or involuntary eye movements, prompt assessment is needed to investigate the middle and inner ear and other neurological causes.
Discharge colour alone does not distinguish mites, yeast and bacteria. Brown wax can also occur in a healthy ear without pain or itching. Changes from before, discharge amount and other signs matter. Observations of both ears help even if your cat scratches only one side.
Complications and consequences
Untreated otitis externa can lead to:
- Spread into the middle and inner ear.
- Eardrum damage.
- Neurological complications, including vestibular syndrome and head tilt.
- Chronic disease and continuing discomfort.
- Complete or partial deafness.
Cats can also have middle ear disease without obvious otitis externa. Neurological signs are therefore not dismissed because the canal looks clean. Prolonged shaking and scratching can also damage the ear flap and cause a haematoma within it. A thick, swollen ear flap needs separate assessment.
Diagnosis at the vet
An accurate diagnosis may use:
- Otoscopy to examine the canal and eardrum.
- Microscopic examination of an ear sample for mites, bacteria and fungi.
- Bacterial culture in chronic or severe disease.
- Blood tests for systemic disease.
- X-rays or CT if middle or inner ear disease or a tumour is suspected.
History covers onset, previous ear medicines and cleaners, skin symptoms, parasite control and possible signs in other animals. Report recurrence in the same ear and worsening after any product.
Otoscopy assesses canal openness, discharge, foreign objects and the eardrum. If the ear is very painful or full of discharge, examination and cleaning may require sedation or general anaesthesia. An unseen eardrum cannot be declared intact from external inspection alone.
Cytology identifies bacteria, yeasts and the nature of inflammation. Mites are sought through separate microscopy or otoscopy. Culture may be needed for severe, recurrent or poorly responsive bacterial infection, for example. Sample results help target medicines.
A mass, persistent blockage or suspected middle ear disease may require biopsy or more detailed imaging. CT helps assess deeper changes. Long-standing disease also prompts allergy assessment. Food allergy is investigated where needed through a vet-planned diet trial and challenge, rather than ear discharge alone.
Treatment
Treatment depends on the cause:
- Ear mites require vet-prescribed parasite medicines, such as selamectin or moxidectin, available as spot-on products licensed for cats.
- Bacterial infections require topical or oral antibiotics.
- Fungal infections require antifungal drops.
- Allergies require allergen avoidance and anti-inflammatory treatment.
- Tumours or polyps may require surgery.
Ordinary bacterial or yeast otitis externa is often treated topically. Oral antibiotics are assessed separately, for example for severe or deeper infection. Pain and swelling are treated too, so your cat can tolerate necessary procedures.
Eardrum condition affects drop selection. Not every ear substance is safe if it enters the middle or inner ear. Do not use old ear medicines, another animal's drops or human products yourself. Worsening symptoms after starting a medicine need reassessment.
Ear mite treatment uses a product suitable for your cat. With confirmed infestation, treatment of household cats and dogs is coordinated to prevent transmission cycling between animals. Removing wax alone does not eliminate mites.
An allergen cannot always be completely avoided, making a long-term skin disease management plan necessary. A polyp or another obstructing lesion may instead need removal. Procedure extent depends on location and findings.
Your vet always cleans pus and crusts from the ears. Do not use cotton buds, which can worsen damage.
Cleaning method and timing are selected individually. Do not forcibly flush a very painful ear at home; the practice provides safe instructions. Cleaning is not the first or only step in every situation.
Home care and monitoring
Ask to be shown how to give the prescribed product and handle the ear. Check cleaner and medicine compatibility and any interval between them with your vet. If pain makes your cat resist handling, contact the practice. Treatment may need adapting so it can be performed safely.
Avoid vinegar, hydrogen peroxide and other home remedies, which can irritate an inflamed canal. Use only a suitable cleaner and treat only visible areas you have been instructed to handle. Do not insert instruments deeply.
Monitor itching, smell, discharge, pain and balance. New unsteadiness, hearing changes or clearly worsening pain warrant prompt contact. Follow-up may repeat ear examination and sampling, because less smell alone does not confirm recovery. Do not end medicines early simply because head shaking has decreased.
Prognosis
Prognosis is often good when the cause is found and treatment can be carried out. Recurrence requires review of the underlying cause. Middle or inner ear damage may cause longer-lasting hearing or balance problems even after infection is controlled.
Prevention
- Check your cat's ears regularly.
- Maintain preventive parasite treatment.
- Feed appropriately to reduce allergy risk.
- Prevent injuries and foreign objects entering the ears.
- Treat skin and allergic diseases promptly.
Healthy cat ears do not usually need routine cleaning. A little wax without other symptoms does not mean disease. Parasite control is matched to exposure risk, and even a balanced diet does not guarantee allergy prevention. Repeatedly red, smelly or itchy ears need examination rather than more cleaning.
Important for cat owners
Otitis externa is a common, unpleasant condition causing pain and suffering. Remember that smell, discharge and head shaking are reasons to take your cat to a vet immediately. Earlier treatment improves the chance of avoiding complications and preserving hearing.
This article provides general information and does not replace veterinary care. Contact a vet if you notice signs of illness in your cat.
Frequently asked questions
Does brown earwax always mean ear mites?
No. Brown wax can be normal, and different inflammatory conditions can look similar. Mites are confirmed through examination and sampling where needed.
Can I use previously prescribed ear drops?
Do not treat a new problem with old medicine without advice. The cause may differ, and eardrum condition affects product safety.
Why does the ear become inflamed again?
Allergy, mites, a polyp or middle ear disease may be responsible. If the original cause remains untreated, reducing microbes may help only temporarily.
Should healthy ears be cleaned regularly?
Usually not. Observe the ears, but agree cleaning needs and product choice with your vet if symptoms develop.
This article is for general information only and is not a guide to treatment. If you notice the first signs of illness, contact your vet.
Paw4care editorial team
Sources
- Otitis Externa (External Ear Infection) in Cats, Merck Veterinary Manual, accessed 2026-11-03.
- Chronic Otitis in Cats: Clinical management of primary, predisposing and perpetuating factors, Journal of Feline Medicine and Surgery, accessed 2026-11-03.
- Otitis Media and Interna in Cats (Middle and Inner Ear Infections), Merck Veterinary Manual, accessed 2026-11-03.
- Ear Cleaning and Administering Ear Medication in Cats, VCA Animal Hospitals, accessed 2026-11-03.
- Otodectic Mite, Companion Animal Parasite Council, accessed 2026-11-03.
- Ear Infections in Cats, PDSA, accessed 2026-11-03.
- 2023 AAHA Management of Allergic Skin Diseases in Dogs and Cats Guidelines, AAHA, accessed 2026-11-03.
- Nasopharyngeal Polyps, American College of Veterinary Surgeons, accessed 2026-11-03.
- Initial Triage and Resuscitation of Small Animal Emergency Patients, Merck Veterinary Manual, accessed 2026-11-03.