Fungal Infections in Cats – How Common Are They Really?


Fungal infections in cats, also known as mycoses, are caused by various fungal organisms such as yeasts, molds, and dimorphic fungi. While less common than other feline diseases like upper respiratory infections, fungal infections still impact many cats to varying degrees. Some fungal infections like ringworm are highly contagious, while others may be opportunistic and only affect immunocompromised cats. Fungal infections can lead to skin, respiratory, nervous system, or systemic problems in cats if left untreated. That’s why it is important for cat owners to understand the major types of fungal infections in cats, their causes, and how to get proper diagnosis and treatment from a veterinarian when necessary.

Types of Fungal Infections

Some of the most common fungal infections seen in cats include:

  • Ringworm – This highly contagious fungal infection affects the skin, hair, and nails. It is caused by several types of fungi in the genus Microsporum and Trichophyton. Ringworm often starts as small patches of hair loss that can spread and result in circular lesions on the skin. According to the Merck Veterinary Manual, ringworm is one of the most common skin diseases in cats.
  • Aspergillosis – This systemic fungal infection is caused by Aspergillus fungi and often affects the respiratory tract. Aspergillosis can cause pneumonia, sinusitis, and other upper respiratory issues. It spreads by inhalation of Aspergillus spores.
  • Blastomycosis – Also called blasto, this systemic fungal disease is caused by Blastomyces dermatitidis. It is often localized to the lungs and skin. The fungus thrives in moist, organic material. According to VMSG, blastomycosis mainly affects outdoor cats in certain geographical areas.
  • Histoplasmosis – This systemic fungal infection is caused by Histoplasma capsulatum and can affect the lungs, intestines, central nervous system, and more. It spreads by inhaling spores found in contaminated soil.
  • Cryptococcosis – The Cryptococcus fungi can cause respiratory, neurological, or systemic disease in cats. It is often localized to the nasal cavity and central nervous system.
  • Candidiasis – This localized fungal infection is caused by Candida albicans and often affects the mouth, nose, ears, and gastrointestinal tract. It can cause oral thrush and secondary respiratory infections.

Other less common fungal infections in cats include sporotrichosis, dermatophytosis, hyalohyphomycosis, and more. Fungal infections can be localized to a specific area or systemic, depending on the type of fungus.


Fungal infections in cats can cause a variety of symptoms depending on the type of fungus and which part of the body is affected. Some common symptoms of fungal infections in cats include:

  • Skin lesions, scaly skin, hair loss, itching and scratching – these are typical symptoms of dermatophytosis, a fungal skin infection caused by Microsporum canis, Microsporum gypseum and Trichophyton species (source).
  • Sneezing, nasal discharge, swelling of the nose and face – these symptoms may indicate infection with Cryptococcus, which often affects a cat’s nasal passages and sinuses (source).
  • Gastrointestinal signs like vomiting and diarrhea – a fungal infection in the digestive tract can cause these nonspecific symptoms.
  • Anemia, fever, weight loss, lethargy – systemic fungal infections often cause these general symptoms.
  • Eye symptoms like uveitis, glaucoma and blindness – ocular fungal infections can affect the inner or outer parts of a cat’s eye.
  • Difficulty breathing – fungal pneumonia can cause breathing issues.
  • Lameness – fungi like Blastomyces can infect bones and joints.

In some cases, cats with fungal infections may show no obvious symptoms at all. Fungal cultures and other diagnostic testing are needed to identify the type of fungus and determine the best treatment.

Causes and Risk Factors

Several factors can put cats at an increased risk of developing fungal infections:

Weakened immune system – Cats with feline leukemia virus, FIV, diabetes, cancer or other diseases that impair immune function are more susceptible to fungal infections. A suppressed immune system has difficulty fighting off fungal invaders.

Injuries – Breaks in the skin from wounds, burns or surgeries can provide an entry point for fungus to invade tissue and cause infection. Fungal spores on contaminated objects can infect open wounds.

Allergies – Cats with allergies tend to lick and scratch excessively which damages the skin barrier. This allows fungus to penetrate broken skin and infect underlying tissue.

Moist environments – Damp, humid environments favor fungal growth. Outdoor cats exposed to swamps, moist soil and compost piles are at higher risk. Wet fur from bathing, swimming or rain can also promote fungal overgrowth if not dried properly.

Older age – Senior cats tend to have weaker immune systems and are more prone to skin damage from allergies or scratches. This puts them at increased risk for fungal infections.

Antibiotics – Long-term antibiotic use can kill off normal bacteria in the body that keep fungal growth in check. This allows fungi like Candida to rapidly multiply and cause infections.



Veterinarians use several methods to diagnose fungal infections in cats:

Complete blood count (CBC) to check for elevated white blood cells, which may indicate infection. A CBC analyzes the numbers and types of cells in the blood (Source).

Chemical blood profile to assess organ function and look for potential problems. Blood chemistry tests measure electrolyte, enzyme, and protein levels (Source).

Urinalysis to check kidney function and look for fungal elements in the urine. A urinalysis involves physically and chemically analyzing a urine sample (Source).

Skin scrapings to examine infected skin under a microscope. A vet takes a skin sample and checks for fungal hyphae and spores (Source).

Biopsy of infected tissue to identify the specific fungus involved. Examining a tissue sample can confirm a diagnosis (Source).


There are various treatment options available for fungal infections in cats depending on the type and severity of infection. According to VMSG, most fungal infections are treated with oral or topical antifungal medications prescribed by a veterinarian. Some common antifungal medications used include itraconazole, fluconazole, terbinafine, ketoconazole, and miconazole.

For mild superficial fungal infections limited to the skin and hair, topical antifungal creams, ointments, shampoos, or dips may be prescribed. These are applied directly to the infected areas on the skin or coat. For more severe or systemic fungal infections, oral antifungal medications are usually necessary. These are given by mouth and treat infections affecting multiple areas of the body.

In addition to medications, keeping the skin clean and dry can help combat fungal infections. The veterinarian may recommend wiping down the cat’s coat with antifungal shampoos or rinses. Trimmed hair around infected areas also allows topical medications to penetrate better. Prompt treatment is important to control the infection and prevent it from spreading to other pets or humans.

Most fungal infections will clear up within a few weeks if proper treatment is given. However, the full course of medication should always be completed as prescribed even if symptoms resolve earlier. Follow-up vet visits are recommended to monitor progress and confirm the infection has been eliminated.


There are several steps cat owners can take to help prevent fungal infections in their pets:

Groom your cat regularly using a comb or brush to remove dead hair and skin cells where fungi can grow. Be gentle and don’t break their skin. Brush daily if your cat has long hair.[1]

Bathe your cat periodically with an antifungal shampoo prescribed by your vet. This helps reduce fungal overgrowth on their skin and fur. Don’t bathe too frequently though, as that can dry out their skin.[2]

Keep your home clean and dry. Vacuum and mop floors regularly, especially bathrooms and kitchen where moisture can accumulate. Fix any leaks and clean up spills right away to discourage fungal growth.[3]

Allow proper ventilation and airflow in your home to prevent a humid environment. Use fans, dehumidifiers, and air conditioning as needed.[1]

Avoid letting your cat go outside in damp weather. Keep litter boxes clean and dry as well.

Maintain your cat’s overall health with proper nutrition and hygiene. A healthy immune system will be better able to resist fungal infections.

Watch for early signs of fungal infection like hair loss or skin irritation, and take your cat to the vet promptly for diagnosis and treatment.


The prognosis for fungal infections in cats can vary greatly depending on the type of infection, how severe it is, and whether it receives prompt treatment.[1] Without proper treatment, some fungal infections like ringworm can spread and become quite serious, leading to hair loss and lesions across the body.[2] However, with appropriate antifungal medication prescribed by a veterinarian, many mild to moderate fungal infections can be fully cured within a few weeks.[3]

For infections limited to the skin and hair follicles, the prognosis is generally good if treatment begins early before the infection spreads. Topical antifungal creams, medicated shampoos, and oral medications can help clear up most minor fungal infections. More resistant fungal infections may require long-term treatment over months, but cats often respond well if the medication regimen is followed consistently.[1]

Systemic fungal infections that affect multiple organs carry a guarded prognosis. These types require stronger oral antifungal drugs and long treatment durations. While complete cures are possible, relapses may occur in some cats. Close monitoring and follow-up care is essential.[2] For cats with weakened immune systems, the prognosis is poorer and the infection may be chronic or fatal if it cannot be controlled.[3]

With appropriate veterinary care and by following treatment instructions carefully, the prognosis for most fungal infections in cats is good. However, delays in treatment or interrupting medication too soon can allow the infection to persist and worsen the prognosis.

When to See a Vet

It’s important to take your cat to the vet if you notice any signs of a possible fungal infection. Some key signs that warrant a vet visit include:

  • Skin lesions, sores, or abnormal growths on the skin
  • Hair loss, scaly/flaky skin patches, or crusty areas on the skin
  • Excessive scratching, licking, or irritation of the skin
  • Changes in nail or claw appearance
  • Swelling or discharge around the eyes, nose, or mouth
  • Sneezing, coughing, or respiratory distress
  • Lethargy, loss of appetite, or other signs of illness

A vet will perform diagnostic tests like skin scrapings, biopsies, or fungal cultures to identify the type of fungal infection. Proper diagnosis is essential for determining the right antifungal medication or treatment. Delaying veterinary care can allow the infection to worsen and spread. For suspected systemic, internal fungal infections affecting multiple organs, immediate vet care is crucial.

Even if you successfully treat a topical fungal skin infection at home, it’s wise to follow up with a vet. They can confirm the fungus is eliminated and provide tips for prevention and monitoring. Catching infections early and maintaining regular vet checkups for at-risk cats is key to successful treatment and prevention of fungal infections.


In summary, fungal infections are relatively common in cats, with ringworm being the most prevalent. While some fungal infections like ringworm are superficial, others like blastomycosis can become systemic and life-threatening if left untreated. Symptoms vary based on the type of infection but often include skin lesions, respiratory issues, fever, weight loss, and lethargy. Risk factors include exposure to infected soil, compromised immune system, and chronic diseases like diabetes. Diagnosis is made through clinical signs, skin scrapings, biopsies, blood tests, and imaging. Treatment depends on the type and severity of infection but often includes topical and oral antifungal medications. While some fungal infections can resolve on their own, most require veterinary treatment. Prevention involves keeping the environment clean, reducing exposure to wildlife, and maintaining a healthy immune system. With prompt diagnosis and treatment, the prognosis for fungal infections in cats is often good. Being aware of the signs and getting veterinary care when needed can help pet parents manage fungal infections in their cats.

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