Aspergillosis in Dogs: Causes, Symptoms & Treatment Guide

Aspergillosis is a fungal infection that affects dogs and is caused by the Aspergillus fungus, which commonly exists in soil, hay, and dust environments. Many dogs are exposed to this fungus regularly without any issues. However, aspergillosis tends to develop mainly in dogs with weakened immune systems or pre-existing health conditions. This detailed guide covers the causes, symptoms, diagnosis, and treatment options for aspergillosis pertinent to dog owners in the United States in 2025.

Understanding Aspergillosis in Dogs

Aspergillosis arises due to infection by Aspergillus fungi, especially A. fumigatus, which is widespread throughout many environments. This is an opportunistic infection, meaning it primarily impacts dogs whose immune defenses are compromised. Healthy dogs typically fight off this fungus successfully. When infection takes hold, it often complicates other underlying health issues.

There are two main forms of aspergillosis in dogs:

• Nasal Aspergillosis: A localized infection primarily affecting the nasal cavity and sinuses.
• Disseminated Aspergillosis: A much more severe, systemic infection that spreads beyond the nasal area to multiple organs.

Nasal Aspergillosis: The More Common Form

This form usually affects long-nosed breeds, also known as dolichocephalic breeds, like Greyhounds and Afghan Hounds due to their long nasal passages providing a suitable environment for fungal growth.

The fungus enters through the nostrils, settling in the nasal passages and sinuses, causing inflammation and damage to the mucous membranes and occasionally the underlying bone. This condition can be painful and distressing for affected dogs.

Signs of Nasal Aspergillosis

• Repeated sneezing episodes
• Unexplained nosebleeds (epistaxis)
• Rubbing or pawing at the nose, a sign of irritation or discomfort
• Nasal discharge ranging from clear to thick, colored, or pus-filled

Disseminated Aspergillosis: When the Infection Spreads Systemically

Disseminated aspergillosis is a less common but much more serious disease where the fungal spores spread beyond the nasal cavity to affect organs like the lymph nodes, kidneys, spleen, bones, and eyes. In the U.S., German Shepherds are especially vulnerable to this form, likely due to genetic and immune system factors.

Symptoms of Disseminated Aspergillosis

• Overall lethargy and listlessness
• Loss of appetite, vomiting, diarrhea, and noticeable weight loss
• Eye complications, including blindness in advanced cases
• Joint pain and limping caused by fungal infection in the joints
• Persistent wounds that produce pus

How Veterinarians Diagnose Aspergillosis

Diagnosis depends on the type of infection and often involves several veterinary diagnostic tools to confirm the fungal presence and evaluate how far the infection has spread.

Tests for Nasal Aspergillosis

Common diagnostic steps include:

• Rhinoscopy: using an endoscope to directly view the nasal cavities and collect swabs for fungal culture
• Imaging techniques like X-rays or CT scans to detect fungal plaques and check for bone involvement
• Lab culture of fungi from the nasal swabs, which typically grows the causative organism reliably

Diagnosing Disseminated Aspergillosis

Because the systemic form affects many organs, diagnosis is more complicated and may involve:

• Blood and urine tests to examine systemic spread
• Ultrasounds and radiographs to inspect organs involved
• In some cases, biopsies from affected organs

Available Treatment Strategies for Aspergillosis in Dogs

Treatment differs depending on the form and severity of the infection. Early diagnosis improves the chances for successful treatment significantly.

Managing Nasal Aspergillosis

This form is generally more treatable. Treatment typically involves:

1. Nasal irrigation and removal of fungal plaques: Under general anesthesia, veterinarians flush the nasal passages to physically clear fungal spores and plaques. Surgical removal of fungal material might be needed in more severe cases to boost treatment success.
2. Topical antifungal therapy: Antifungal medications like 1% clotrimazole solution are applied directly to the nasal passages and sinuses, sometimes requiring multiple treatments prior to resolution.
3. Systemic antifungal drugs: Oral medications such as itraconazole, posaconazole, or terbinafine may be prescribed to assist in the clearance of the infection.

Approach to Treating Disseminated Aspergillosis

This form is challenging to treat effectively. It requires long-term systemic antifungal therapy, often for several months or longer. Commonly used drugs are:

• Posaconazole: A newer antifungal that shows promise but is often expensive.
• Itraconazole: The standard oral antifungal, though sometimes less effective in systemic infections.
• Terbinafine or Fluconazole: Some veterinarians combine these with azoles for improved effects.

Unfortunately, the outlook remains guarded to poor despite aggressive treatment, with a high risk of relapse. Constant veterinary monitoring and supportive care play crucial roles.

Final Thoughts: Prompt Recognition and Veterinary Care Are Crucial

Though uncommon, aspergillosis can cause serious health issues in dogs—especially breeds like German Shepherds that may have genetic predispositions. Early identification of symptoms, whether persistent nasal signs or unexplained systemic illness, combined with swift veterinary consultation, greatly improves treatment success.

For those considering breeds susceptible to aspergillosis, such as German Shepherds, it is wise to acquire puppies from reputable breeders and maintain regular check-ups with your veterinarian to catch any health concerns early.

If your dog exhibits any symptoms described here, reach out to your veterinarian promptly to discuss diagnostic testing and treatment options, ensuring your faithful companion receives the optimal care they deserve.