Learn about body fungus, including skin fungus and systemic fungal infections.

What is a Fungal Infection?

Fungal infections affect cats and dogs just like they do in humans. Most parasitic fungi live as organisms in the soil - decaying leaves, plants, feces and animal matter.

There are several types of fungal infections and these include:

Blastomycosis is caused by the fungal organism. Blastomyces dermatitidis which breeds in moist soil that is rich in bird or bat droppings. This infection develops when the fungal spores are inhaled and typically affects one or all of the body systems – for example, the respiratory system, nervous system, musculoskeletal system and the skin. It is common in dogs but rarely cats. Common symptoms and signs include coughing, fever, rapid breathing, pneumonia, lesions or seizures.

Candidiasis is common in both dogs and cats, and is caused when there is an overgrowth of candida in the body of the animal. It may develop in one specific part of the body or spread to the entire body. It typically affects the skin, gastrointestinal system including the oral cavities. Common symptoms include white, cotton-like growths in the mouth, crusty skin lesions, fever or diarrhea.

Coccidiomycosis is caused by the Coccidiodes immites organisms and affects the respiratory organs but can spread to other parts of the body. It affects dogs and cats, but tends to be more common in young, large-breed, male dogs.

Cryptococcosis is caused by a yeast-like fungus, Cryptococcosis neoformans found in contaminated soil of bird droppings. Although, it affects both cats and dogs, cats are more predisposed to this infection. This infection occurs as a result of inhaling fungal spores and affects the upper respiratory system, nervous system and the eyes. Common symptoms include coughing, sneezing, breathing difficulties, nasal discharge and drainage, swelling of the eye, trouble walking, and circling as well as movement discoordination. Cryptococcosis can be quite severe, infecting the nervous system and eyes.

Dermatophytosis (ringworm) is caused by fungal spores in the environment and typically develops on the skin as lesions. It is highly contagious and affects both dogs and cats. Common symptoms include red, raised, crusty skin and circular patches of dry skin with hair loss.

Histoplasmosis is caused by Histoplasma capsulatum organism which can be found in organically enriched soil or bird manure. This infection develops when contaminated dust is inhaled and affects dogs, cats and humans. It affects the respiratory system starting in the lungs and then spreading to other parts of the body such as the spleen, gastrointestinal tract, bone marrow, liver and eyes. Common symptoms include coughing, fever, diarrhea, weight loss, lameness, skin changes and depression.

What Causes Fungal Infections?

Animals often develop these infections through ingestion or inhalation of the soil or the air. These infections range from mild skin infections to debilitating, often life-threatening systemic diseases.

Diagnosing Fungal Infections

The diagnosis of fungal infection is based on the symptoms presented and physical examination. Certain laboratory tests such as viewing the organism under a microscope, x-rays, smears collected from the skin, needle aspirations from the lungs, or biopsy of the intestines may be performed. Additional tests may also be performed to rule out any other health disorders.

Help for Fungal Infections

Treatment depends on the type of fungal infection, the severity of the infection and your pet’s overall health. Your vet may prescribe anti-fungal shampoo or creams, or fungicidal antimicrobial medications. In more serious case, surgery may be performed and intravenous fluids administered. These medications can be very costly and may have some harsh side effects.

More Information on Fungal Infections