Runny Nose in Cats

Brittany Kleszynski, DVM
By Brittany Kleszynski, DVM on Jun. 14, 2023
Cat runny nose

A healthy cat’s nose is typically moist and cool, but there are many situations where his nose can feel or look a bit off. A runny nose can be caused by many conditions that vary in severity. Runny noses are especially common in young kittens or cats with compromised immune systems.

Any time your cat develops a runny nose, schedule an appointment with a primary care veterinarian to determine the underlying cause. If your cat also has breathing difficulties, bloody nasal discharge, a high fever, or extreme lethargy, he should receive emergency medical attention immediately.

Why Does My Cat Have a Runny Nose?

Cats develop runny noses in response to irritation or inflammation within their nasal passages. This can be due to various types of infections and conditions, or due to foreign material. Nasal discharge can vary in consistency, amount, and color. In many cases, the cause of a runny nose can be contagious among cats. Therefore, it is best to separate a cat with a runny nose from other cats in the household until a diagnosis is made.

What to Do if Your Cat Has a Runny Nose

If your cat develops a runny nose, bring him to the veterinarian for evaluation. It’s important to determine the underlying cause and rule out anything serious. At home, a warm towel can be used to gently wipe away nasal discharge and crusts that can cover the nostrils.

Nasal discharge can range from a thin, clear fluid to a thick, yellow or green mucus.

A humidifier can help break up any congestion your cat may have.

Additional symptoms you may notice include:

  • Fever

  • Decreased appetite

  • Nasal congestion

  • Noisy breathing

  • Eye discharge

Sneezing, coughing, and pawing at the face are also common. Serious symptoms to watch for include extreme lethargy, difficulty breathing, and blood-tinged nasal discharge. If any of these signs are present, call the veterinarian right away.

Causes of Runny Nose in Cats

There are various reasons why cats develop runny noses, including:

  • Feline Respiratory Disease Complex: Feline respiratory disease complex refers to respiratory tract infections caused by viruses and bacteria. Most commonly, these are due to viruses, such as feline herpesvirus and calicivirus. Upper respiratory infections are especially common in kittens and immunosuppressed adult cats, such as those with FeLV or FIV.  These cats often experience fevers, mouth sores, sneezing, eye inflammation, and eye discharge in addition to runny noses.

  • Fungal Infection: Many types of fungi, such as Aspergillus and Cryptococcus, can infect the nasal cavities of cats. This usually occurs when cats inhale or directly contact fungal spores. These infections can cause a variety of symptoms along with runny noses, including behavioral changes due to their harmful effects on the nervous systems of cats.

  • Allergic Rhinitis: Allergic rhinitis is inflammation within the nasal cavity due to allergen exposure. Dander, pollen, grass, and many other substances can trigger a runny nose along with itchy, watery eyes and bouts of sneezing in cats.

  • Nasal Polyp: Nasal polyps are most common in kittens, but they can affect cats of any age. Polyps are small, benign masses that develop within the nasal passages. They usually cause nasal discharge on the side of the nostril that contains the polyp as well as frequent sneezing.  

  • Oronasal Fistula: Cats with severe dental disease may develop an opening between the nasal and oral cavities, a condition called oronasal fistula. This uncomfortable condition often results in sneezing and one-sided nasal discharge.

  • Cuterebra (botfly larva): Botfly larva are a type of fly that can infest a cat’s nasal cavity. Cats can come into contact with botfly larva when they sniff around rabbit and rodent nests. The larva enters the nasal cavity where it either stays or migrates to other areas of the body. Cats with a botfly larva in one of their nostrils may have runny noses, breathing difficulties, and sneezing fits.

  • Aspiration pneumonia: When cats accidentally inhale stomach contents, such as during surgery, the lungs can become irritated and inflamed. Pneumonia develops within the lungs, which results in nasal discharge that is yellow or green, a harsh cough, and noisy breathing.

  • Foreign Body: If a cat accidentally inhales a foreign object, it can become lodged inside the nasal cavity. This leads to inflammation and subsequent nasal discharge.

Trauma, high blood pressure, toxin ingestion, clotting disorders, cancer, and tick-borne diseases are all potential causes of blood-tinged nasal discharge in cats, which should be addressed immediately.

How Veterinarians Diagnose the Cause of Runny Nose in Cats

A veterinarian will perform a full physical exam to assess the overall health of the cat. The veterinarian will pay special attention to the heart, lungs, eyes, mouth, and nose. This includes looking into the nostrils for any obvious abnormalities. Temperature will also be taken to check for a fever.

Sometimes a visual exam is all that is needed to determine the cause of a cat’s runny nose. However, if additional information is helpful, a veterinarian may also perform the following tests:

  • Blood work: A small sample of blood is collected to check for signs of disease, clotting deficiencies, or toxin ingestion.

  • Nasal Cytology: A small sample of nasal discharge is collected and examined under the microscope to check for bacteria, fungi, and abnormal cells.

  • PCR: A sample of nasal discharge can be collected and submitted to a laboratory to identify abnormalities through advanced testing.

  • Imaging: A chest X-ray is helpful to check for underlying lung issues that may be contributing to a runny nose. Advanced imaging, such as a CT or MRI, can be useful in identifying polyps or tumors.

  • Rhinoscopy: Under sedation, a scope is passed through the nasal passages to identify any abnormalities, such as tumors, foreign objects, or polyps. Biopsies can be taken during this procedure if needed.

Treatment for Runny Nose in Cats

Treatment depends on the underlying cause of the runny nose. First and foremost, cats should be stabilized upon arriving to the veterinary hospital. For example, if a cat with nasal discharge presents with difficulty breathing, supplemental oxygen should be given immediately. Some cats may require hospitalization and supportive care if they are extremely sick. Others may need surgery to correct the underlying problem and resolve the runny nose.

Common medications that may be prescribed to treat a runny nose in cats include the following:

The veterinarian can determine an appropriate treatment plan based on the underlying cause and overall health of your cat. Pet parents should always give these medications only as prescribed by the veterinarian.

To reduce stress during recovery, cats should have a private, quiet area to rest. Pet parents should ensure their cats are eating and drinking well during this time. If any symptoms begin to worsen, cats should be brought to a veterinarian immediately.  

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Brittany Kleszynski, DVM


Brittany Kleszynski, DVM


Dr. Brittany Kleszynski is a veterinarian and freelance medical writer who specializes in creating meaningful content that engages readers...

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