Yeast Infection and Thrush in Cats

By PetMD Editorial on Jan. 12, 2009

Candidiasis in Cats

Candida is a type of sugar-digesting yeast that forms part of the normal flora in an animal's mouth, nose, ears, and gastrointestinal and genital tracts. Although it is a normal part of the body, this type of yeast is opportunistic and will sometimes colonize or invade the damaged tissues of immuno-suppressed animals. Left unchecked, candida can quickly grow to abnormal levels. Candidiasis is the medical condition that occurs when there is an overgrowth of candida in the body.

This type of fungal infection can afflict cats of any age and breed, even if the cat has no predisposing conditions. The infection can take place in a specific part of the body (local), or it can colonize the entire body (systemic). Either affliction is likely to cause extreme discomfort.


How the symptoms of candidiasis manifest depend largely on where the infection takes place. In the case of an ear infection, a common symptom is constant shaking and scratching at the head. If candida settles in the oral cavity, there will usually be an abnormal amount of drooling. If it involves the urinary bladder, your cat may experience inflammation of the bladder (cystitis). Inflammation around areas where intravenous (IV) catheters and gastronomy tubes have been inserted, skin irritation, open sores on the skin (ulcerative lesions), and correlating fever are common symptoms that these sites have been invaded by candida.


The causes and risk factors of candidiasis are numerous. Cats that have skin that has been traumatized, is damaged by burns, or that has dying and inflamed tissue (necrotizing dermatitis) carry an increased risk of acquiring the condition. The same can be said for cats which have neutropenia, a viral (parvovirus) infection, the feline leukemia virus (FeLV), or the feline immunodeficiency virus (FIV). Existing conditions that can open the door to the candida fungus are diabetes, and urinary retention caused by narrowing of the ureter tubes (typically following a urethrostomy, an artificial opening from the urethra through the perineum to allow urine to pass). Conditions which call for indwelling catheters can also place animals at a higher risk for contracting candidiasis.


The diagnostic procedure for candidiasis can be carried out in a number of ways. In case of lesions, a biopsy to confirm or dismiss diseased tissue will be conducted. The results of the biopsy will determine whether or not yeast organisms have penetrated the affected tissues. A urine sample will also be taken. The presence of candida colonies in the urine, along with a simultaneous bacterial infection in the urinary tract will point to candidiasis. The urine analysis will also show yeast forms, or clumps, of mycelial elements. If fever is also present, tips of catheters will also be cultured for both bacteria and fungi. Infected tissues will typically contain a white, cheesy foci. Tests will find large numbers of yeast organisms in inflamed tissues where candidiasis is present.


Treatment for candidiasis involves improving and strengthening the immune system. In the case of diabetes, there is also a critical need to regulate the condition's complications and control hyperadrenocorticism. If your cat has any indwelling catheters, they must be removed. Medications that are typically used to treat candidiasis are applied to the skin or to otherwise affected areas.

Living and Management

After the symptoms of candidiasis have subsided, treatment should be continued for two more weeks, ideally. Then, a culture of the infected areas must be re-taken to determine if the condition has been resolved. Because candidiasis is often symptomatic of an underlying disease, such as diabetes, it is of utmost importance that such diseases are controlled.


There are currently no known preventative measures.

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