Fungal infections aren’t always the first thing pet parents think of when their dog starts itching, coughing, or acting “off,” but they’re more common than many people realize. Some fungal infections in dogs affect only the skin, while others can involve the lungs or other internal organs. The symptoms can be subtle at first and may look like allergies, bacterial infections, or minor skin irritation.
Because fungal infections vary widely in severity, understanding the different types, recognizing early warning signs, and knowing when to seek veterinary care can make a meaningful difference in your dog’s comfort and recovery. This UrgentVet guide breaks it all down in a clear, practical way, so you know what to watch for and what steps to take next.
Types of Fungal Infections in Dogs
Fungal infections in dogs can be grouped into two broad categories: those that primarily affect the skin and those that involve internal organs. Some are relatively easy to treat, while others require longer-term medical management.
Fungal Skin Infections
A fungal skin infection in dogs typically develops when fungi naturally present in the environment or on the skin grow out of balance. These infections often appear in moist areas such as skin folds, ears, paws, or around the groin. Dogs with allergies, weakened immune systems, or chronic moisture exposure may be more susceptible.
Ringworm
Despite its name, ringworm (dermatophytosis) is a fungal infection, not a parasite. Pets can contract it from contaminated soil, as well as from other animals. It causes circular areas of hair loss, scaling, and sometimes redness or crusting. Ringworm in dogs is contagious to other pets and people, making prompt diagnosis and treatment especially important in multi-pet households.
Yeast Infection
Yeast is a type of fungus that normally lives on a dog’s skin, but overgrowth can lead to irritation and inflammation. Yeast infections in dogs commonly affect the ears, paws, armpits, and belly, often causing itchiness, redness, and a distinctive odor. Chronic yeast infections may signal underlying allergies or hormonal conditions.
Systemic Fungal Infections
Systemic fungal infections occur when fungal spores are inhaled or enter the body and spread beyond the skin. These infections are less common but can be serious and require prompt veterinary care.
Blastomycosis
Blastomycosis is caused by inhaling spores found in moist soil and decaying organic matter. It often affects the lungs but can spread to the skin, eyes, bones, and lymph nodes. Dogs may show respiratory signs, fever, weight loss, or eye inflammation.
Cryptococcosis
Cryptococcosis is associated with soil contaminated by bird droppings, particularly pigeon droppings. It can affect the respiratory system, nervous system, eyes, and skin. Nasal discharge, swelling around the nose, or neurological signs may occur.
Coccidioidomycosis
Also known as Valley Fever, this infection develops after inhaling fungal spores found in dry, dusty soil. It is most common in certain regions of the southwestern United States. Dogs may show coughing, lethargy, lameness, or fever.
Histoplasmosis
Histoplasmosis is caused by fungi found in soil enriched with bird or bat droppings. It commonly affects the lungs and gastrointestinal tract. Symptoms may include diarrhea, weight loss, coughing, or breathing difficulty.
Aspergillosis
Aspergillosis can affect the nasal passages or become systemic in rare cases. Dogs with nasal aspergillosis may have nasal discharge, nosebleeds, facial pain, or swelling around the muzzle.
Signs of Fungal Infection in Dogs
The symptoms and signs of fungal infection in dogs depend on whether the infection is localized to the skin or involves internal organs. They also may develop gradually and can vary in severity.
Common signs include:
- Persistent itching or scratching, especially if it doesn’t respond to typical allergy treatments
- Hair loss or patchy bald spots, sometimes with redness or scaling
- Skin discoloration or thickening, often in chronic cases
- Ear infections that keep returning, with redness, discharge, or odor
- Lameness or joint pain, which may occur with systemic infections
- Coughing or difficulty breathing, especially in fungal infections affecting the lungs
- Weight loss or decreased appetite, often seen in more advanced infections
- Lethargy or behavioral changes, such as reduced energy or reluctance to exercise
If your dog is showing a combination of these symptoms (or has symptoms that continue to worsen), veterinary evaluation is recommended.
Diagnosing Fungal Infections in Dogs
Diagnosing a fungal infection often requires a combination of medical history, physical examination, and diagnostic testing. Your veterinarian may ask about your dog’s environment, travel history, recent activities, and how long symptoms have been present.
Diagnostic tools may include skin scrapings, fungal cultures, cytology, blood tests, urine tests, or imaging such as X-rays if a systemic infection is suspected. In some cases, biopsy or advanced testing may be needed to confirm the diagnosis and determine the specific type of fungus involved.
Because fungal infections can mimic other conditions, proper testing is essential before starting treatment.
Treatment Options for Fungal Infections in Dogs
Treatment options for dog fungal infections depends on the type, location, and severity of the infection. Mild skin infections may resolve relatively quickly, while systemic infections often require months of therapy. Determining how to treat fungal infection in dogs varies case by case, but common treatment approaches include:
- Topical antifungal treatments: Medicated shampoos, sprays, wipes, or creams are commonly used for localized skin infections. These products help reduce fungal overgrowth, calm irritation, and support skin healing, but they must be used consistently for the full recommended duration.
- Oral antifungal medications: Widespread, recurrent, or systemic fungal infections often require prescription oral medications. These drugs work throughout the body and may be needed for several weeks to months. Periodic bloodwork may be recommended to monitor liver function during long-term therapy.
- Supportive care: Dogs that feel unwell may benefit from additional support such as pain relief, anti-inflammatory medications, appetite support, or fluids. This helps keep them comfortable while antifungal treatment does its work.
- Environmental management: Cleaning bedding, grooming tools, and living spaces helps reduce re-exposure to fungal spores. Limiting access to damp or high-risk environments during treatment can also support recovery.
- Follow-up and rechecks: Repeat exams or testing may be needed to confirm the infection has fully resolved, especially for systemic cases. Stopping treatment too early can lead to relapse.
When it comes to fungal infection in dogs, skin treatment and oral medication are effective only when exactly as prescribed, even if symptoms improve early. Consistency is key.
Preventing Fungal Infections in Dogs
While it’s not possible to eliminate all risk, prevention focuses on minimizing exposure and supporting healthy skin and immune function.
- Keeping your dog clean and thoroughly dried after swimming or bathing is especially important, as moisture creates an ideal environment for fungal growth. Pay close attention to ears, paws, skin folds, and areas where hair is dense.
- Regular grooming and routine skin checks at home can help you spot early changes, such as redness or odor, before they progress.
- Dogs with allergies or chronic skin issues benefit from proactive management, as ongoing inflammation can make fungal infections more likely.
- Limiting access to areas with heavy dust, standing water, or decaying organic matter (particularly in regions where systemic fungal diseases are common) can also reduce risk.
Finally, consistent veterinary wellness care plays a key role in prevention by identifying vulnerabilities early and keeping your dog’s overall health on track. It’s never too late to make preventative visits a habit.
Need Veterinary Assistance? Find an UrgentVet Near You!
If your dog is showing symptoms that could indicate a fungal infection, UrgentVet is here to help. Our veterinary teams can evaluate symptoms, perform diagnostics, and create a treatment plan that supports your dog’s comfort and long-term health.
For more information and to receive quick, compassionate care, find your neighborhood UrgentVet location and walk in or schedule an appointment online today.
FAQs About Dog Fungal Infections
What Happens If a Fungal Infection Is Left Untreated in Dogs?
Untreated dog fungal infections can worsen over time, spread to other parts of the body, and cause significant discomfort or illness. Systemic infections may become life-threatening without proper treatment.
How Do You Know If Your Dog Has a Bacterial or Fungal Infection?
Bacterial and fungal infections can look very similar. Diagnostic testing is often required to identify the cause, which is why veterinary evaluation is important before starting treatment.
Is My Dog’s Fungal Infection Contagious?
Some fungal infections, such as ringworm, are contagious to other pets and people. Others are not spread through direct contact. Your veterinarian can explain precautions if needed.
Can Dogs Get Valley Fever From Soil Fungus?
Yes. Dogs can develop Valley Fever after inhaling fungal spores from disturbed soil in certain regions, particularly dry, desert-like environments.
Where Is the Valley Fever Fungus Primarily Found?
The fungus responsible for Valley Fever is most commonly found in the southwestern United States, including parts of Arizona, California, New Mexico, and Texas.
Can Fungal Infections in Dogs Be Considered an Emergency?
Some fungal infections in dogs can become urgent, especially if they affect breathing, the eyes, or the nervous system. If your dog seems unwell or symptoms are rapidly worsening, veterinary care should be sought promptly.
Photo Credit: MariaZubareva / Shutterstock
