Nasal Polyps in Cats

What are nasal polyps?

Nasal polyps are benign (non-cancerous) fleshy growths that develop in the nasal passages. Similar polyps can occur above the soft palate (the soft tissue at the back of the roof of the mouth) or within the ear canal.

Nasal polyps develop from the cells that line the nasal passages. These polyps consist mainly of inflammatory cells covered by a layer of epithelial cells (similar to skin cells) that extend over the surface of the polyp. Polyps may grow up to 1-2 cm (0.4-0.8 in.) in length and can extend into the nasal passages or the ear canal.

Nasal polyps are most commonly seen in young cats, although older cats can also be affected. Nasal polyps can occur in cats of any breed.

What are the signs of nasal polyps?

The signs of nasal polyps can vary depending on the location of the polyp. The signs often mimic those of an upper respiratory infection, but they may persist despite treatment. Commonly observed signs include:

• Sneezing
• Noisy breathing
• Nasal congestion
• Trouble breathing

You may also notice reduced airflow through one nostril by placing your hand in front of your cat’s nose or watching your cat breathe onto a piece of glass. In a cat with healthy nasal passages, you should see two small areas of condensation on the glass, one from each nostril. If a nostril is obstructed, you may only see one area of condensation. Sometimes there will be discharge from the eyes or nose. In some cases, nasal polyps may extend from the nasal passages into the throat. These nasopharyngeal polyps can cause more severe signs, including:

• Difficulty breathing and swallowing
• Ear-related signs, such as frequently tilting the head to one side, pawing at the ears, and frequent or recurrent ear infections

What causes nasal polyps?

The cause of nasal polyps is not fully understood. Genetics may play a role, making some cats more likely to develop nasal polyps than others. Certain viral respiratory infections may also contribute to the development of nasal polyps by triggering inflammation.

How are nasal polyps diagnosed?

Your veterinarian may be able to detect a nasal polyp during an examination, although sedation may be required. In other cases, your veterinarian may use specialized procedures to see the polyp, such as rhinoscopy (a camera passed into the nasal passages) or endoscopy (a camera passed into the throat).

In some cases, your veterinarian may need additional imaging tests to diagnose nasal polyps. Your veterinarian may perform radiographs (X-rays) of your cat’s skull (under sedation or general anesthesia) or may recommend a CT scan or MRI to better evaluate the nasal passages. 

How are nasal polyps treated?

Nasal polyps can often be surgically removed using traction or avulsion (pulling the polyp free from its attachment). With your cat under general anesthesia, your veterinarian will use forceps to grip, twist, and pull the polyp free from its attachment.

Laser ablation (removal of the polyp with a laser) and other specialized techniques can also be used to treat nasal polyps. These techniques are less commonly used but may be beneficial in some cases.

In some cases of polyps in the ears, a surgical technique called a ventral bulla osteotomy may be used. This procedure involves opening the hollow chamber below the ear to remove the polyps more completely, which can significantly reduce the risk that the polyps will return.

After removing the polyps, your veterinarian may prescribe antibiotics to prevent infection. Your veterinarian may also prescribe a gradually decreasing dose of a steroid (such as prednisone) to reduce inflammation and lower the risk of recurrence. Your veterinarian may recommend submitting the polyp to a veterinary pathologist to confirm that it is not cancerous and does not contain evidence of infection.

What is the long-term outlook?

Polyps removed with traction or avulsion have a 15% to 50% chance of returning. Because the underlying cause of nasal polyps remains unknown, there is currently no reliable way to prevent recurrence. If your cat’s nasal polyps recur after treatment, they will likely need to be surgically removed again.