When to see a vet urgently
Seek prompt assessment if ear symptoms are accompanied by any of the following:
- Your cat tilts its head, falls over or loses its balance.
- The eyes move involuntarily or one side of the face appears to droop.
- The ear is very painful and your cat will not let you touch its head.
Balance problems should not be attributed to an ordinary yeast infection, as they may be associated with inner ear disease. You can find a vet near you.
Overview
Malassezia pachydermatis and related species live on the skin and in the ear canals of healthy animals without causing problems. When immune defences weaken or skin conditions change, yeast multiplies excessively, resulting in inflammation: dermatitis or otitis. Changes most commonly affect the ears, face, neck, abdomen and spaces between the toes.
Finding yeast in a sample does not establish disease on its own. Yeasts can be present on the skin or in the ears of a cat without symptoms, and numbers vary with the individual and sampling site. Assessment of inflammation combines skin or ear changes with microscopic examination. Malassezia is a less common cause of skin inflammation in cats than in dogs.
Causes
The main causes of Malassezia overgrowth include:
- allergic diseases, including atopic dermatitis and food allergy;
- hormonal and metabolic diseases, such as diabetes and hyperthyroidism;
- parasitic conditions, including flea allergy and mites;
- bacterial skin infections;
- reduced immunity after illness or treatment;
- increased skin moisture and greasiness.
The list describes possible underlying factors, but their importance is less well established in cats. Research on the association between diabetes and yeast overgrowth is conflicting, and hyperthyroidism alone does not establish the cause of a yeast infection. However, yeast involvement in itching has been described in allergic cats: yeasts have been found on inflamed skin, and antifungal treatment has sometimes reduced symptoms. The allergy may still need its own treatment after yeast numbers fall.
Risk factors
- Cats with chronic allergies or skin inflammation.
- Cats with weakened immune defences.
- Cats living in damp conditions.
- Breeds prone to skin problems, such as Sphynx, Devon Rex and Persian cats.
- Chronic or recurrent ear inflammation.
Research on feline risk factors is limited, so this list should not be used to make a diagnosis. Sphynx and Devon Rex cats may carry more yeast than usual even without obvious skin inflammation. In Persians, yeast overgrowth has been described with a particular type of facial dermatitis. Breed, greasy skin or environmental humidity alone does not indicate whether a cat needs antifungal medication.
Typical symptoms
- Intense itching, constant licking or scratching.
- A greasy coat and sticky skin.
- An unpleasant yeasty or rancid smell.
- Red, thickened skin.
- Localised hair loss.
- In the ears: dark, brownish or yellowish discharge, ear canal inflammation and head shaking.
Symptom severity varies. A cat may not scratch intensely despite greasy scaling on the skin or brown, firmly attached debris around the claws. In an allergic cat, several areas may be affected, such as the face, underside of the neck and abdomen. Bacterial infection can occur in the same area too.
The colour or smell of ear discharge does not identify the cause. Ear mites, bacteria and yeasts can cause similar symptoms or occur together. At the appointment, explain whether one or both ears are affected, whether there have been similar problems before and what has already been put into the ears. Sampling before cleaning helps assess the original situation.
Complications and consequences
Without treatment, Malassezia dermatitis and otitis lead to:
- chronic itching and skin inflammation;
- deep infections involving secondary bacterial disease;
- thickening and darkening of the skin;
- chronic ear inflammation that can lead to deafness;
- a substantial reduction in quality of life.
These are possible consequences, not the inevitable progression of every yeast infection. Malassezia usually causes superficial inflammation. With deep infection or hearing loss, bacteria, long-term ear canal changes and middle or inner ear disease must also be assessed. Outer and inner ear inflammation are different conditions. In cats, middle ear inflammation may also be associated with respiratory disease or a polyp and does not always spread from the outer ear.
Diagnosis at the vet
To confirm the diagnosis, investigations include:
- cytology of a skin or ear discharge sample to detect yeast cells;
- cultures in chronic cases;
- investigation of underlying diseases, including allergies and hormonal disorders.
Skin and ear samples
Skin samples can be collected with adhesive tape, by pressing a microscope slide against the skin or by swabbing discharge. The method depends on the lesion. Microscopy looks for inflammatory cells and bacteria as well as yeasts. Yeast numbers are interpreted alongside symptoms: a positive culture alone does not show that yeast explains all the skin changes.
Culture is not automatically needed for every cat. A routine fungal culture is not equivalent to assessing skin yeast numbers either, and the method must suit the question being investigated. If suspicion remains but no yeasts are found, the vet may sample other affected areas or consider other diagnoses.
The ears are examined with an otoscope. This also assesses canal swelling, discharge, possible tumours or polyps and the condition of the eardrum. Thorough examination of a very painful or blocked ear may require sedation. An ear sample also investigates the possibility of mites.
When is systemic disease investigated?
Sudden, widespread greasy skin and hair loss may require investigation of the cat's overall health. Yeast has also been described in skin changes associated with serious internal diseases and tumours. This association does not mean every cat with yeast-related symptoms has a tumour. A localised chin lesion and widespread skin disease, for example, may need different further investigations. Tests are selected according to skin findings, general condition and other symptoms.
Treatment and follow-up
Topical and oral treatment
Yeast-related skin inflammation can be treated with topical antifungal products chosen by the vet. Options include shampoos, creams or wipes. Selection depends on the size of the affected area, skin sensitivity and whether treatment can be carried out at home. The product's suitability for cats and its instructions must be checked specifically. A product intended for a dog's skin is not automatically suitable for a cat.
In some cases, the vet prescribes an oral antifungal medicine. A concurrent bacterial infection is treated according to its own needs: antifungal medicine does not replace assessment of bacterial infection, and antibiotics do not treat yeast. An underlying allergy or other skin disease needs its own treatment plan. The response also depends on whether the underlying condition can be controlled.
Treating ears safely
Ear medication is selected according to sample findings and eardrum condition. Not every product is suitable for an ear with a damaged eardrum. Do not start leftover drops from a previous infection on your own. Copious discharge may need removal at the practice so the ear can be examined and medication can reach the affected area.
At home, clean only as instructed by the vet. Products containing alcohol or hydrogen peroxide can irritate an inflamed ear. Do not insert cotton buds into the ear canal: they can injure the canal or eardrum and push discharge deeper. If cleaning hurts, stop and contact the treating vet. Ask for a practical demonstration of the order of cleaning and medication when needed.
Follow-up compares both symptoms and new samples. Continuing itching after yeast has cleared may indicate an underlying disease is still active. If yeast and symptoms remain, medication administration and treatment suitability are reassessed. Do not change treatment on smell or skin appearance alone.
Prevention
- Treat allergies and chronic skin inflammation promptly.
- Check and care for your cat's ears regularly.
- Maintain good hygiene and avoid excessive moisture in your cat's environment.
- Use medicated shampoos as directed by the vet.
- Arrange regular veterinary visits if your cat is prone to skin problems.
Healthy ears without symptoms generally do not need routine cleaning. Excessive cleaning can itself irritate the ear canal. Checking primarily means watching for discharge, odour, redness and changes in behaviour. If an ear becomes painful or red, investigate the cause before changing cleaning products.
Important for cat owners
Malassezia skin and ear inflammation in cats often results from other diseases. Treatment therefore needs to address the whole problem: as well as antifungal medicines, the underlying cause, such as allergy, hormonal disease or parasites, needs treatment. If your cat starts scratching a lot and develops greasy, unpleasant-smelling skin, do not postpone a veterinary visit.
This article provides general information and does not replace veterinary care. If you notice signs of illness in your cat, contact a vet.
Frequently asked questions
Can yeast be present in a cat's ear without inflammation?
Yes. Some cats carry yeasts without ear symptoms. Microscopic findings are therefore interpreted alongside redness, pain, discharge and other examination findings. An isolated yeast finding in an ear without symptoms is not enough on its own to start medication.
Why does a yeast infection return after treatment?
An underlying allergy or another disease affecting skin conditions may continue even when yeast is temporarily controlled. An unrecognised underlying cause in the ear may also sustain inflammation. Recurrence needs examination and sampling to confirm that this is still the same problem.
Will antifungal medicine alone stop an allergic cat's itching?
Itching may improve if yeast overgrowth contributes to inflammation. Such responses have been described in allergic cats. However, treatment does not remove the allergy itself, so remaining itching or new skin changes may require allergy investigation and treatment.
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
- Biology, diagnosis and treatment of Malassezia dermatitis in dogs and cats, World Association for Veterinary Dermatology, accessed 2026-11-03.
- Malassezia Dermatitis in Dogs and Cats, University of Illinois College of Veterinary Medicine, accessed 2026-11-03.
- Malassezia spp. overgrowth in allergic cats, Veterinary Dermatology / PubMed, accessed 2026-11-03.
- Retrospective study: the presence of Malassezia in feline skin biopsies. A clinicopathological study, Veterinary Dermatology / PubMed, accessed 2026-11-03.
- Otitis Externa in Animals, Merck Veterinary Manual, accessed 2026-11-03.
- Otitis Media and Interna in Animals, Merck Veterinary Manual, accessed 2026-11-03.
- Instructions for Ear Cleaning in Cats, VCA Animal Hospitals, accessed 2026-11-03.