When your pet develops sneezing, noisy or “sniffly” breathing, or nasal discharge, it can be frustrating when initial treatments only seem to help temporarily.

In many cases, treatments such as antibiotics, antihistamines, or other supportive medications may provide temporary improvement, but the symptoms often return. When this happens, the next step is determining the underlying cause through advanced nasal diagnostics.

Common Causes of Nasal Disease in Dogs and Cats

There are several potential causes of nasal disease in dogs and cats. These include nasal tumors, fungal infections such as Aspergillus, tooth root abscesses (as the tooth roots are located just below the nasal cavity), and chronic allergic rhinitis, which can be challenging to manage.

Foreign material in the nose (such as plant debris) or nasal mites are also possible, although they are less commonly seen in the Houston area.

In cats, previous viral infections can alter the normal structure of the nasal passages, leading to chronic inflammation. This inflammation may result in the development of polyps in the middle ear or back of the nasal cavity.

More unusual causes of chronic nasal disease in dogs and cats include scar tissue formation in the back of the nasal passages (stenosis), trauma, or congenital abnormalities affecting the sinuses.

Why It Can Be Difficult to Diagnose Nasal Issues in Pets

With multiple possible causes, narrowing down nasal issues in pets can be challenging. In some cases, a pet’s history, age, and physical exam findings may be suggestive of a particular cause.

For example, swelling along the bridge of the nose, below the eye, or along the palate may suggest a tumor, polyp, or abscess. Complete nasal obstruction in an older pet is more concerning for a tumor; in a younger cat, a polyp may be more likely. Heavy tartar buildup or inflamed gums can also point toward a tooth root abscess or a connection between the tooth and nasal cavity. However, a large portion of the tooth root sits beneath the gumline, so dental disease isn’t always obvious just by looking during an exam.

The Role of Imaging in Diagnosing Nasal Disease in Pets

While the physical exam can help narrow down possibilities, it usually isn’t enough to reach a definitive diagnosis.

X-rays of the head are often limited in their usefulness for diagnosing nasal disease in pets, as the structures of the nose and mouth overlap in two-dimensional images. A CT scan provides detailed, three-dimensional images of the nasal cavity and the back of the throat. This allows for a more complete evaluation of the affected area.

What About Rhinoscopy?

Rhinoscopy (scoping of the nose) can be helpful in certain situations, particularly for identifying foreign material or evidence of fungal disease.

However, the scope can be advanced only through the front of the nostrils to a limited depth and then redirected to view the back of the nasal passages. A large portion of the nasal cavity cannot be visualized using rhinoscopy alone.

Because of this limitation, performing rhinoscopy without prior imaging carries a risk of missing the diagnosis. In many cases where rhinoscopy is performed alone, a CT scan is still needed afterward to complete the evaluation.

Why Biopsies Are Often Necessary

For many pets with chronic nasal disease, biopsies are required to reach a definitive diagnosis. Biopsies allow for evaluation by a pathologist, identification of inflammatory conditions such as chronic rhinitis, culture to detect infection, and classification of tumors when present.

Without biopsy results, it can be difficult to determine the most appropriate treatment plan.

Common Questions About Advanced Nasal Diagnostics for Pets

• “Are there blood tests that can diagnose nasal disease?” Bloodwork is routinely performed prior to anesthesia to ensure safety, but it rarely provides a diagnosis for nasal disease in dogs and cats. There are blood tests that can suggest exposure to fungal organisms such as Aspergillus; however, a positive result does not confirm infection within the nasal cavity, and a negative result does not rule it out.

• “Can antifungal medication be tried without a diagnosis? For fungal infections such as Aspergillus in the nose, oral antifungal medications are generally not effective. Instead, treatment typically requires an infusion of antifungal medication directly into the nasal cavity under anesthesia. Other fungal infections may respond to oral medications, but treatment often requires several months, and improvement is not immediate. Starting treatment without a diagnosis may delay appropriate care, particularly if the underlying cause is a tumor or another condition.

• “Can rhinoscopy be performed without a CT scan? While it is possible to perform rhinoscopy in dogs and cats alone, it is not typically recommended because a large portion of the nasal cavity cannot be visualized and it is possible to miss the diagnosis.

What to Expect from Veterinary Nasal Diagnostics

When a diagnosis cannot be made based on exam findings alone, a CT scan performed under general anesthesia is typically the next step.

Based on findings:

• If a tumor is identified, biopsies can be obtained to determine the tumor type.

• If a tooth root abscess is identified, referral to a veterinary dentist may be recommended.

• If no clear cause is identified, rhinoscopy and biopsies can be performed during the same anesthetic event.

This approach allows for a more complete evaluation while minimizing the need for multiple procedures.

The Goal of Advanced Nasal Diagnostics for Pets

The goal of advanced nasal diagnostics for pets is to better understand what is causing your pet’s symptoms and determine what treatment options are available.

If your pet is experiencing ongoing nasal signs and you have been referred for further evaluation, we hope this information helps clarify the diagnostic process and what may be recommended next.

Learn more about GCVS’ Internal Medicine departments by visiting the website.

Written In Consultation With:

Melissa Clark, DVM, PhD, DACVCP, DACVIM