Why Does My Cat Have a Yeast Infection? The Surprising Causes


Yeast infections in cats, also known as yeast dermatitis or Malassezia dermatitis, are skin infections caused by an overgrowth of yeast. The most common yeast involved is Malassezia pachydermatis. These infections can occur on the skin, ears, mouth, and other areas. Some common symptoms include greasy skin, hair loss, itchiness, redness, and a rancid odor.

While not extremely common in cats, yeast infections do occur and can cause discomfort. Prevalence is estimated to be around 5-10% in the general cat population. Certain breed predispositions exist, such as Siamese cats. Yeast dermatitis often develops secondary to other conditions like allergies or hormone imbalances.


Yeast is naturally present on a cat’s skin and within the gastrointestinal and genitourinary tracts. However, certain situations can allow yeast to grow out of control and cause an infection (Source).

Some common causes and risk factors for yeast overgrowth in cats include:

  • Hot, humid weather that creates a moist environment where yeast can thrive
  • Allergic skin disease leading to inflammation and increased yeast on the skin
  • Antibiotic therapy which kills off competing bacteria allowing yeast to flourish
  • Dietary allergies or sensitivities causing gastrointestinal changes
  • Endocrine disorders like diabetes or Cushing’s disease
  • Wounds, burns, or other skin trauma
  • Folds or creases in the skin that harbor yeast
  • A weakened or suppressed immune system

In some cases, an underlying cause cannot be identified. But factors that allow overgrowth of yeast already present on the body tend to precipitate infections in cats.

Areas Affected

Yeast infections in cats most commonly affect the ears, paws, mouth, and skin folds. According to PetMD, the ears are often affected as yeast loves the warm, moist environment. Signs of an ear infection include head shaking, scratching at the ears, and black discharge. The paws can also become infected, especially between the toes where moisture gets trapped. A yeast infection between the toes is called pododermatitis and causes itching, redness, and licking of the paws.

The mouth is another warm, moist area where thrush may occur. Oral thrush causes plaque, drooling, and difficulty eating or swallowing. Fungal infections can also develop in the moist skin folds on the face, lips, tail, and body. WagWalking notes that signs include greasy yellow crusting, hair loss, and itching in the folds.


To diagnose a yeast infection in cats, veterinarians will first perform a physical examination and look for common signs like skin irritation, ear inflammation, and other symptoms. They may take a sample of the infected skin or ear and examine it under a microscope to look for an overgrowth of yeast.

One of the main ways vets diagnose yeast dermatitis is by performing skin scrapings. Using a scalpel blade, the vet will gently scrape the affected area of skin onto a microscope slide. Then they will apply a stain and examine the sample under a microscope. An overgrowth of yeast like Malassezia will be visible if yeast is the cause of the skin irritation (Source).

In addition to skin scrapings, vets may use fungal cultures or cytology to diagnose yeast infections. For ear infections, they will thoroughly examine the ear canal for signs of inflammation and take a swab sample. Diagnostic tests along with the cat’s symptoms and medical history will allow the vet to determine if a yeast overgrowth is responsible for the infection.

Risk factors

There are certain risk factors that can increase a cat’s chance of developing a yeast infection. According to PetMD (PetMD), some of the main risk factors include:

Age – Older cats are more prone to yeast infections due to weaker immune systems.

Obesity – Overweight cats tend to have more skin folds where yeast can thrive.

Allergies – Allergies can cause skin irritation that allows yeast to grow.

Antibiotics – Antibiotics kill off good bacteria needed to keep yeast under control.

Diabetes – High blood sugar allows yeast to proliferate.

Other risks according to WagWalking (WagWalking) include prolonged use of corticosteroids, a compromised immune system, and humid or unclean living conditions.


Treatment for yeast infections in cats often involves antifungal medications prescribed by a veterinarian. Common antifungal medications used include ketoconazole, fluconazole, itraconazole, and posaconazole (Source). These medications are typically given orally and can be used for infections affecting the skin, ears, bladder, or other parts of the body.

Medicated shampoos containing antifungal ingredients like miconazole, chlorhexidine, or ketoconazole may also be prescribed for topical treatment of skin yeast infections. These help eliminate fungi on the skin surface and control symptoms like itching and scaling (Source). Shampoo therapy usually lasts 2-4 weeks.

Dietary changes may also be part of an effective yeast infection treatment plan. Your vet may recommend switching to a grain-free or low-carb diet to discourage yeast overgrowth. Probiotic supplements can help restore healthy gut flora as well (Source). With prompt treatment, most yeast infections in cats can be cured within a few weeks.

Home care

There are several ways to help care for a cat with a yeast infection at home naturally. Keeping the affected areas clean, dry, and disinfected is important to prevent the infection from worsening or spreading.

Gently clean the infected areas with a soft damp cloth and pat dry. Avoid rubbing, which can further irritate the skin. Disinfect grooming tools like combs and brushes after each use to prevent reinfection. According to WagWalking, medicated shampoos containing ingredients like miconazole nitrate or ketoconazole can also help treat yeast on the skin when used as directed.

Probiotics can be very effective for treating yeast infections in cats internally. As explained by Nusentia, probiotics help restore healthy gut flora, which inhibits the overgrowth of yeast. Look for probiotic supplements formulated specifically for cats. Providing probiotic-rich foods like plain yogurt may also be beneficial.

Keep your cat comfortable by providing soft bedding away from direct sunlight. Monitor for signs of pain or worsening of symptoms. Contact your veterinarian if the infection persists or worsens despite home treatment.


There are several steps cat owners can take to help prevent yeast infections in their pets. Proper nutrition is important, as yeast thrives on carbohydrates and sugar. Feeding high-quality protein sources like meat, fish, and eggs can help starve yeast (source). Additionally, probiotics added to food or given as supplements can help restore healthy gut bacteria to fight off yeast overgrowth (source).

Regular grooming and hygiene is another prevention method. Trimming hair around moist areas like the eyes, mouth, and rear can increase airflow and reduce trapped moisture where yeast likes to grow. Gentle cleansing with a mild, pet-safe shampoo can also help (source). It’s also important to identify and manage any allergies or skin conditions that may allow yeast to take hold.

Keeping living spaces clean and dry can decrease environmental moisture that enables yeast growth. Using air conditioning in hot months and dehumidifiers can help. It’s also wise to wash bedding frequently and disinfect any areas where yeast infections have occurred to prevent recurrence.


Yeast infections in cats can lead to complications if left untreated. One potential complication is the infection spreading to other areas of the body. Yeast infections often start in moist areas like the ears, paws, mouth or around the genitals. From there, they can spread to other parts of the skin and cause lesions and hair loss (https://wagwalking.com/cat/condition/yeast-infection-thrush). The infection may also spread internally and affect organs like the bladder or digestive tract.

Another complication of yeast infections is skin damage. The yeast overgrowth can cause severe itching, which leads cats to excessively lick, bite and scratch themselves. This self-trauma can result in wounds, sores and skin infections. The skin may become thickened, scaly and discolored. In severe cases, the skin may crack and bleed. This allows bacteria to enter and cause secondary infections (https://wagwalking.com/cat/condition/fungal-yeast-infection). Prompt treatment is important to minimize skin damage and prevent the infection from embedding deeper into the skin.

When to see a vet

If your cat has a persistent yeast infection that does not improve with home treatment, you should take them to see a vet. According to WagWalking, a yeast infection that persists beyond two weeks of treatment requires veterinary attention.

You should also consult a vet if your cat shows signs of pain or distress due to the infection. Scratching, head shaking, crying, or changes in behavior could indicate discomfort requiring medical intervention. As noted on PetMD, ear infections in particular can cause severe irritation.

Other symptoms that warrant veterinary assessment include fever, appetite loss, vomiting, diarrhea, and lethargy. Your vet can examine your cat, diagnose the cause of these symptoms, and provide appropriate treatment. Proper diagnosis and care from a vet is crucial for resolving persistent or complex yeast infections in cats.

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