Fungal infections in dogs can range from simple skin irritations to serious systemic conditions affecting internal organs. This type of infection can occur when certain types of fungi take hold in a dog’s body, either externally on their skin or internally in their lungs, bones, or other tissues. 

Some dog fungal infections, like ringworm, are superficial and relatively easy to treat. Others, like Blastomycosis or Histoplasmosis, can be life-threatening if not caught early. Here’s a quick guide on everything you need to know about dog fungal infections.

Types of Dog Fungal Infections

Fungal infections in dogs differ by type, which can bring different symptoms and treatment methods. Here are some of the most common types of dog fungal infections:

Yeast Dermatitis

Yeast dermatitis is a superficial fungal infection caused by the overgrowth of Malassezia pachydermatis, a yeast that naturally resides on a dog’s skin. While typically harmless, this yeast can multiply excessively under certain conditions, such as allergies, humidity, or a weakened immune system. 

The infection often targets areas like the ears, paws, armpits, and skin folds, making it especially common in breeds with floppy ears or wrinkled skin. These breeds include basset hounds, poodles, and dachshunds.

Symptoms of Yeast Dermatitis

• Persistent itching and scratching.

• Red, inflamed, or irritated skin.

• Oily or greasy patches are often accompanied by scaling or flaking.

• Discoloration of the skin, with a darker appearance in chronic cases.

• A distinct odor emanating from the affected areas.

• Recurring ear infections, with redness, discharge, or head shaking.

Ringworm

Despite its name, ringworm isn’t caused by a worm but by dermatophyte fungi such as Microsporum canis. This superficial fungal infection affects a dog’s skin, hair, and nails. It’s highly contagious and can easily spread through physical contact with infected animals and contaminated objects.

Puppies, seniors, and dogs with impacted immune systems tend to be more susceptible to this disease. Ringworm is also zoonotic, meaning it can be transmitted to humans.

Symptoms of Ringworm 

• Circular patches of hair loss.

• Redness or inflammation in the affected areas.

• Brittle or damaged nails if the fungus infects the claws.

• Mild to severe itching accompanied by discomfort.

• Scaly or crusty skin, with dryness and irritation present.

Blastomycosis

Blastomycosis is a systemic dog fungal infection caused by Blastomyces dermatitis, a fungus found in moist soil, decaying wood, and areas near water. Dogs typically contract the infection by inhaling fungal spores.

These spores then travel to the lungs and may spread to other parts of the body, such as the skin, bones, brain, and lymph nodes. This infection is more common in areas where water is present.

Symptoms of Blastomycosis

• Respiratory problems such as coughing and breathing problems.

• Fever and urinary issues.

• Weight loss and decreased appetite.

• Enlarged lymph nodes.

• Skin lesions or sores that may ooze or crust over.

• Lameness or swelling.

Histoplasmosis

Histoplasmosis is caused by Histoplasma capsulatum. Dogs can contract the fungus by inhaling or ingesting them through soil enriched with bird or bat droppings. Because of this, histoplasmosis primarily affects the respiratory system. 

Dogs under the age of 4 are usually the most common victims of this disease. In some cases, the infection can spread to the gastrointestinal system, liver, spleen, or other organs.

Symptoms of Histoplasmosis

• Chronic coughing or difficulty breathing.

• Fever and general lethargy.

• Weight loss and poor appetite.

• Diarrhea and vomiting.

• Enlarged lymph nodes.

Coccidioidomycosis

Coccidioidomycosis, also known as Valley Fever, is a systemic dog fungal infection caused by the Coccidioides fungi. These fungi thrive in dry, dusty environments.

Dogs typically contract the infection by inhaling fungal spores from soil, especially after digging or being exposed to windblown dust. The infection primarily affects the respiratory system but can spread to bones, joints, or the nervous system in severe cases.

Symptoms of Coccidioidomycosis

• Persistent coughing or wheezing.

• Fever and lack of energy.

• Weight loss and poor appetite.

• Lameness or swollen joints if the fungus spreads to bones.

• Neurological symptoms, such as seizures, in rare advanced cases.

Cryptococcosis

Cryptococcosis is another fungal infection in dogs caused by Cryptococcus neoformans or Cryptococcus gattii. These fungi are commonly found in soil contaminated with bird droppings, especially from pigeons. 

Dogs can contract the fungal infection by inhaling fungal spores, which primarily affect the respiratory system. In severe cases, the infection can worsen and spread to the central nervous system, eyes, or skin.

Symptoms of Cryptococcosis

• Sneezing and nasal discharge, often with blood or mucus.

• Coughing, sneezing, and breathing problems.

• Neurological symptoms, such as head tilt, seizures, or difficulty walking.

• Eye abnormalities, including cloudiness or blindness.

• Lethargy, fever, and weight loss.

Aspergillosis

Aspergillosis is a dog fungal infection caused by species of the Aspergillus fungi commonly found in soil, decaying vegetation, and dust. Dogs typically contract the infection by inhaling fungal spores, which primarily affect the nasal passages or, in rare cases, spread to other body parts.

Certain breeds, like German Shepherds, tend to be more prone to the disseminated form due to a genetic predisposition.

Symptoms of Nasal Aspergillosis

• Nasal discharge with a strong odor.

• Sneezing and frequent nose rubbing.

• Swelling or pain around the nose or face.

• Nasal sores or ulcers.

Symptoms of Disseminated Aspergillosis

• Fever and overall weakness.

• Lameness and lack of coordination.

• Weight loss and poor appetite.

• Neurological symptoms in severe cases.

Diagnosing Dog Fungal Infections

Accurately diagnosing dog fungal infections is essential for effective treatment. Here’s how we do it: 

Physical Examination

To diagnose dog fungal infections, we’ll start with a physical exam to look for visible signs. These signs might include skin lesions, nasal discharge, swollen lymph nodes, or hair loss. We’ll also need to ask you questions about symptoms you observe at home.

Laboratory Tests

Lab tests for detecting a fungal infection in dogs, such as blood and urine tests, are often used. These can reveal markers of systemic infections or detect antibodies and antigens specific to certain fungi.

Additionally, biopsy, cytology, and microscopy techniques can be used to obtain a definitive diagnosis. Once samples are taken from the affected areas, a quick lab examination can help detect the fungi causing the infection.

Fungal cultures can also be used to accurately determine the fungus responsible for the infection. A sample of infected tissue, fluid, or discharge is cultured in a lab to grow and identify the fungus. By doing so, we can identify the specific fungus causing the disease.

Imaging Studies

Imaging techniques like X-rays, CT scans, or MRIs can also be used to evaluate the condition of your dog’s internal organs, lungs, or bones. These are especially useful in cases where dog fungal infections are affecting these organs and structures.

Treating Dog Fungal Infections

The treatment process for fungal infections in dogs will consist of a mix of antifungal medications and supportive treatments. The specific combination will depend on the type and severity of the infection, as well as the overall health of the dog.

Antifungal Medications

For superficial infections like yeast dermatitis or ringworm, these diseases can often be managed with topical treatments such as antifungal shampoos, creams, or sprays. These are designed to reduce fungal growth on the skin.

For systemic infections or severe cases of superficial infections, oral medications are commonly prescribed. These drugs work by targeting fungal cells internally. Additionally, antifungal drugs can be administered intravenously for faster and more effective treatment.

Fungal infections typically require prolonged treatment, often lasting weeks or even months, to ensure the infection is completely eradicated. Stopping medication too soon can lead to recurrence or resistance.

Supportive Care

Supportive care will involve a nutritional diet. Ensuring your dog receives proper nutrition can strengthen their immune system and aid recovery. Anti-inflammatory drugs or pain relievers may also be prescribed to improve comfort, especially in cases with severe symptoms.

Preventing Dog Fungal Infections

Preventing fungal infections in your dog involves a range of measures that focus on avoiding exposure, strengthening immunity, and maintaining good hygiene. Here’s a guide on how you can protect your dog from fungal infections:

Limit Exposure to Outdoor Environments

Avoid letting your dog dig or play in moist soil, decaying wood, or areas contaminated with bird or bat droppings. If your dog does play in the dirt, make sure to give them a good bath with a good pet-friendly shampoo afterward.

Strengthen Your Dog’s Immune System

A healthy immune system is an important guard for preventing dog fungal infections. Feed your dog a balanced diet with good nutrition to help keep its body protected. Make sure your dog has its vaccinations and parasite control treatments in check, as diseases can weaken its immune system.

Maintain Good Hygiene

Regular grooming and bathing keep your dog’s skin healthy and less vulnerable to fungal overgrowth. Additionally, it’s also important to keep your dog’s toys, bedding, and living areas clean to minimize the risk of a fungal infection in dogs.

Schedule Routine Vet Visits

Regular visits to our clinic can help detect dog fungal infections early. These checkups allow us to monitor your dog’s health and provide the best treatments and recommendations to keep your best friend in good health.

Conclusion

Fungal infections in dogs can lead to serious systemic illnesses, but with awareness and proactive care, many of these infections can be managed and prevented effectively.