Aspergillosis in Dogs: Causes, Symptoms & Treatment Explained

Aspergillosis is a fungal infection affecting dogs, caused by the common Aspergillus fungus found in environments like soil, hay, or dust. While many dogs encounter this fungus daily without issue, aspergillosis manifests mainly in dogs with weakened immune systems or underlying health concerns. In this comprehensive guide, we explore what aspergillosis is, the different types, symptoms, diagnosis, and treatment options relevant for UK dog owners in 2025.

What is Aspergillosis in Dogs?

Aspergillosis results from an infection by Aspergillus fungi, especially A. fumigatus, widespread in the environment. It is an opportunistic infection, which means it primarily affects dogs with compromised immunity. Healthy dogs usually resist this fungus effectively. When infection occurs, it typically complicates other existing health issues.

There are mainly two recognised forms of aspergillosis in dogs:

• Nasal Aspergillosis: Localised infection of the nasal cavity and sinuses.
• Disseminated Aspergillosis: A more severe, systemic infection that spreads beyond the nose to other organs.

Nasal Aspergillosis: The Common Presentation

Nasal aspergillosis primarily affects long-nosed or dolichocephalic breeds such as Greyhounds and Afghan Hounds due to their extensive nasal cavities which provide a favourable environment for fungal growth.

The fungus invades through the nostrils and settles in the nasal passages and sinuses, causing inflammation and damage to the mucous membranes and potentially underlying bone. This infection can be painful and distressing for the dog.

Symptoms of Nasal Aspergillosis

• Frequent sneezing fits and increased sneezing
• Unexplained nosebleeds (epistaxis)
• Pawing or rubbing at the nose indicating discomfort
• Nasal discharge, which may be clear (serous), thick and coloured (mucoid), or contain pus (purulent)

Disseminated Aspergillosis: When the Infection Spreads

Disseminated aspergillosis is a rare but serious condition where the fungal spores spread beyond the nasal area to affect multiple organs, including lymph nodes, kidneys, spleen, bones, and eyes. German Shepherd Dogs are particularly susceptible to this form, potentially due to genetic and immune factors.

Symptoms of Disseminated Aspergillosis

• General lethargy and tiredness
• Loss of appetite, vomiting, diarrhoea, and weight loss
• Eye problems, including blindness in severe cases
• Joint pain and lameness due to infection in joints
• Persistent open wounds with pus discharge

How is Aspergillosis Diagnosed?

Diagnosis depends on the infection form and involves a range of veterinary tests to confirm fungal presence and assess the spread.

Diagnosing Nasal Aspergillosis

Diagnosis commonly includes:

• Rhinoscopy: using an endoscope to visually inspect the nasal cavities and take swabs for fungal culture.
• Imaging: X-rays or CT scans to detect fungal plaques and bone involvement;
• Laboratory fungal cultures from nasal swabs, which grow the fungus reliably.

Diagnosing Disseminated Aspergillosis

Because it affects multiple organs, diagnosis is more complex. Procedures may include:

• Blood and urine tests to assess systemic involvement.
• Ultrasound and radiographs to examine affected organs.
• In some cases, biopsy of other organs.

Treatment Options for Aspergillosis in Dogs

Treatment depends on the form and severity of the infection. Early detection improves outcomes significantly.

Treating Nasal Aspergillosis

This form is more accessible and often treatable. Key treatment steps include:

1. Nasal Flushing and Debridement: Under general anaesthetic, vets flush the nasal passages to physically remove fungal spores and plaques. Surgical debridement may be done in severe cases to enhance effectiveness.
2. Topical Antifungal Therapy: Antifungal drugs such as clotrimazole are applied directly into the nasal passages and sinuses, often requiring multiple treatments for complete resolution.
3. Systemic Antifungals: Oral antifungal medications like itraconazole may be prescribed to assist in clearance.

Treating Disseminated Aspergillosis

This form poses a significant challenge. Treatment involves prolonged systemic antifungal therapy, often for several months. Medicines include:

• Posaconazole: A newer antifungal showing promise in extending life but costly.
• Itraconazole: Traditional choice but often less effective in disseminated disease.
• Terbinafine or Fluconazole: Sometimes used in combination.

Unfortunately, the prognosis is often guarded to poor despite treatment, with relapse common. Close veterinary monitoring and supportive care remain essential.

Conclusion: Early Detection and Veterinary Guidance are Vital

Aspergillosis in dogs is uncommon but can cause serious health issues, especially in immunocompromised breeds like German Shepherds. Recognising signs early, especially persistent nasal symptoms or unexplained systemic illness, and consulting your vet promptly can improve treatment success.

For owners thinking about acquiring a susceptible breed, such as German Shepherds, it is important to obtain puppies from reputable breeders and ensure regular veterinary check-ups to minimise health risks.

If you notice your dog displaying any symptoms detailed above, contact your veterinarian to discuss diagnostic testing and possible treatment to ensure your beloved companion receives the best care possible.