Everyone gets a runny nose now and then, even our cats. But if you notice your cat’s nose leaking clear—or even yellow or green—discharge quite often, something is probably going on with its health.

A runny nose is relatively common in cats and could be caused by a few different things. One thing that pet parents don’t always consider, though, is the cat flu. A more serious infection caused by the calicivirus or herpes simplex virus (as well as a few strains of bacteria), the cat flu can take a toll on your pet’s health and potentially affect it for the rest of its life.

What is cat flu?

The symptoms of cat flu are very similar to those of the human cold or flu, but the specific symptoms your cat experiences may change depending on the type of virus or bacteria causing the illness. Calicivirus-type flus are generally milder, while the flu caused by the herpes simplex virus tends to be more severe.

Generally, symptoms of cat flu include the following:

• Runny nose and eyes
• Sore throat
• Sneezing
• Joint and muscle pain
• Mouth ulcers
• Fever
• Lethargy
• Coughing

In adult cats, cat flu is not particularly serious. However, younger cats and immunosuppressed cats are at serious risk of harm if they contract the flu, and the virus could even turn fatal.

Cat flu can cause secondary health problems in all cats, including bacterial infections of the nasal cavity, dehydration and weight loss. There are also more severe risks that occur in some cats. For example, eye damage is relatively common because the flu has the tendency to cause eye ulcers, which can result in blindness or the loss of the eye.

Regardless of how old your cat is, you should take it to see a veterinarian if you think it has the cat flu, because it should be vaccinated and accurately diagnosed for the best treatment.

Cats can spread the flu through discharges of the eye and nose and through saliva, and the virus can survive in the air for up to one week. Infected food bowls and toys are some of the most common ways the infection spreads.

Treating cat flu

The cat flu generally lasts between one and two weeks. Unfortunately, there are no effective medicinal treatments for the cat flu. The best way to bring your cat back to full health is by getting it vaccinated and taking care of it at home.

Make sure to keep the infected cat away from any other cats in your household, as the flu is extremely contagious. Set up a comfortable quarantine area for your feline friend, so it can recover in peace.

You’ll want to care for the cat by wiping away discharges and encouraging the cat to eat and drink as much as you can. Offer lots of sardines, roasted chicken and water mixed with food; these foods are strong-smelling and easy for your cat to eat with a sore throat.

Most adult cats recover, but typically remain carriers of the virus for the rest of their lives. The chances of re-infection may occur during periods of stress for the cat, but most cats live their lives without additional symptoms.

Other potential causes of runny noses in cats

If you see your cat’s nose running, take a moment to examine its other symptoms. If it doesn’t check most of the boxes for the cat flu, it may actually be dealing with something else entirely.

Here are two more reasons your cat’s nose might be running excessively.

• Allergies: If your cat tends to get a runny nose during certain times of the year, like fall, and also sneezes, itches its body a lot and has puffy eyes, it may actually be suffering from allergies. Cats can become allergic to many things, including certain foods, flea bites, mold, pollen, dust or perfume. Runny noses are common in cats with allergies, but you should get a vet diagnosis to be certain it’s not more serious. If it is allergies, you can work to prevent your cat from having exposure to its allergens and give it allergy supplements to keep it comfortable.
• Bacterial infections: Bacteria can infect the nasal cavity of your cat, also causing a running nose. Many of the symptoms may appear similar to those of the cat flu, but fortunately, bacterial infections can be cleared up more easily than the flu.

Remember to pay close attention to your cat after receiving a diagnosis (no matter what it is) to monitor potential changes in behavior and appearance. If your cat appears to be getting worse, not better, make another trip to the vet to prevent any nasty side effects of these illnesses.