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About Fungal Infections in Dogs

About Fungal Infections in Dogs

Fungal infections can make your dog very sick. In this article, our Fayetteville vets explain some of the most common fungal infections in dogs, their symptoms and how they can be treated.

Types of Fungal Infections in Dogs

While our Fayetteville vets typically see fewer fungal infections in dogs than either bacterial or viral infections, fungal infections can be just as serious and treating fungal infections can be challenging.

Your dog is at risk of developing a fungal infection through various means, such as coming into contact with an infected animal, encountering fungi in the environment, or experiencing an overgrowth of naturally occurring fungi (yeast) on their body.

Fungal infections in dogs can be categorized into two main types: systemic fungal infections that affect the major body systems, and localized fungal infections primarily found on the skin or external features of your dog. It is important to visit your vet for annual vaccinations to prevent any harmful diseases and infections. 

Systematic fungal infections

Systematic fungal infections invade the inner systems of your dog's body, often attacking the dog's lungs, nasal passages, bones or eyes. In the US Aspergillosis, Cryptococcosis, and Blastomycosis are three of the most common systematic fungal infections seen in dogs. 


Cryptococcus is a type of fungus commonly found in areas with large concentrations of pigeons or other birds. When dogs inhale this fungus, it can lead to a lung infection known as cryptococcosis. The infection typically originates in the respiratory tract but can progress to affect your dog's central nervous system, eyes, and skin. Symptoms of cryptococcosis can vary among dogs and may include skin lesions, lethargy, coughing, nasal discharge, eye problems, seizures, and other neurological abnormalities.

The treatment for cryptococcosis in dogs typically involves the use of oral antifungal medications. However, the duration of treatment can be lengthy, often extending for a year or more. It's important to note that cryptococcosis can be challenging to treat, and some dogs may not fully recover from this condition.


Blastomycosis, caused by the fungus Blastomyces dermatitidis, commonly manifests as a lung infection. This fungus thrives in moist, acidic soil rich in decaying vegetation, often found near beaver dams and similar environments. Hunting dogs are particularly at risk of inhaling the fungal spores in these areas. While the initial infection primarily affects the lungs, symptoms of blastomycosis may include coughing, fever, lethargy, loss of appetite, and weight loss. If the infection spreads to other parts of the body, additional symptoms such as lameness, blood in urine, eye problems, skin lesions around the toenails, and fever may arise.

Early diagnosis and treatment are crucial for effective management of blastomycosis. Oral antifungal medications are typically administered and, when initiated promptly, can lead to a complete cure.


Aspergillus is a species of fungus found in soil all around the world and is responsible for two main types of fungal infections seen in dogs:

Nasal Aspergillosis
Nasal aspergillosis primarily affects a dog's nasal passages and sinuses but can progress to involve the bony structures of the nose, as well as occasionally affecting the eye socket and skull. Breeds with long, narrow heads such as greyhounds and collies appear to be more susceptible to this systemic fungal infection.

Symptoms of nasal aspergillosis in dogs include lethargy, bloody nasal discharge or nosebleeds, nasal pain, sneezing, and discomfort around the nose area.

The treatment for nasal aspergillosis typically involves the infusion of a liquid antifungal medication into the affected dog's nasal passages. With appropriate treatment, most dogs recover well, although in some cases, a second round of treatment may be necessary. It's important to work closely with your veterinarian to monitor the progress of treatment and ensure the best outcome for your dog.
Disseminated Aspergillosis
Disseminated aspergillosis is a severe and widespread fungal infection that can affect various parts of a dog's body, including the bones, muscles, and organs. The fungus initially enters the dog's respiratory tract and then spreads through the bloodstream, disseminating throughout the body. This type of infection is more commonly observed in German Shepherds.

The development of disseminated aspergillosis is slow, and it presents with a range of symptoms. These symptoms may include back pain, lameness, loss of appetite, muscle wasting, weakness, vomiting, blood in urine, urinary accidents, swollen lymph nodes, and even paralysis.

Regrettably, the prognosis for dogs with disseminated aspergillosis is generally poor, and the infection is challenging to treat. However, in rare cases, treatment can be successful. It is crucial to consult with a veterinarian experienced in fungal infections to explore potential treatment options and determine the best course of action for your dog.

Localized (Skin) Fungal Infections in Dogs

It can be difficult for pet parents to recognize that their dog has a localized fungal infection because the itching and scratching that go hand-in-hand with these infections is often thought to be the result of dry skin or fleas. Localized fungal infections commonly seen by our vets include ringworm and fungal dermatitis.

Ringworm (Dermatophytes)

Ringworm in dogs is caused by a group of pathogenic fungi. This skin condition is highly contagious and can spread when your dog comes into direct contact with an infected animal, person, or contaminated objects such as furniture, combs, bowls, bedding, or carpets.

Symptoms of ringworm can affect your dog's skin, fur, or nails, and may include hair loss, itching, flaky or crusty skin, and abnormal or brittle nails. To prevent the spread of ringworm to other pets or individuals in your household, early diagnosis and treatment are crucial.

The treatment for your dog's ringworm will depend on the severity of the infection. It may involve a combination of medicated baths, dips, and/or oral antifungal medications. Additionally, frequent vacuuming and disinfection of your home will be important in preventing the spread of ringworm to others within your household.\

Fungal Dermatitis

Fungal dermatitis is a common inflammatory skin condition that occurs when the yeast present in your pet's ears, mucocutaneous areas, and skin overgrows and disrupts the natural balance. This overpopulation of yeast can lead to symptoms such as intense itching, flaky or crusty skin (especially around the nails, skin folds, armpits, and anal area), and ear infections.

The treatment of fungal dermatitis often involves a combination of approaches. Antibiotics may be prescribed to address any secondary infections, while topical antifungal treatments such as shampoos or ear ointments can help combat the overgrowth of yeast.

It's important to note that treating fungal dermatitis may require ongoing efforts, especially if your dog has a compromised immune system or allergies. Some dogs with severe skin allergies may experience recurrent yeast or bacterial skin infections throughout the year. In such cases, your veterinarian will collaborate with you to develop a tailored treatment plan to address your dog's specific health concerns.

Is your dog showing symptoms of a fungal infection? Contact our Fayetteville vets to book an appointment for your pet. 

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