Sneezing fits in cats are most commonly caused by an upper respiratory infection, typically from one of two viruses: feline herpesvirus or feline calicivirus. These two pathogens account for the majority of acute sneezing episodes. But infections aren’t the only explanation. Allergies, foreign objects stuck in the nasal passage, dental problems, and growths in the nose can all trigger repeated sneezing, and the pattern and accompanying symptoms help narrow down the cause.
Upper Respiratory Infections
Feline herpesvirus (also called feline viral rhinotracheitis) is the single most common cause of acute sneezing in cats. It primarily affects the eyes and nose, producing frequent sneezing, watery or goopy eye discharge, nasal congestion, and sometimes drooling. Cats with this virus often sneeze more when they’re excited or moving around. Feline calicivirus causes similar symptoms but tends to hit the mouth and lungs harder, sometimes producing ulcers on the tongue or lips along with nasal and eye inflammation.
Both viruses spread easily between cats, especially in shelters, boarding facilities, and multi-cat households. Kittens and unvaccinated cats are most vulnerable. The sneezing typically starts suddenly, often alongside a fever, and lasts one to three weeks as the infection runs its course. Here’s the catch with herpesvirus: even after a cat recovers, the virus stays dormant in the body and can reactivate during stress, illness, or immune suppression, causing sneezing fits to return weeks, months, or years later.
Vaccination with the core FVRCP vaccine doesn’t completely prevent infection, but it significantly reduces the severity of symptoms. In one study, vaccinated kittens exposed to herpesvirus had meaningfully lower clinical scores for sneezing, nasal discharge, and fever compared to unvaccinated kittens. However, vaccination doesn’t prevent the virus from establishing a latent (hidden) infection, which is why even vaccinated cats can occasionally sneeze from reactivation.
Allergies and Environmental Irritants
Cats can develop allergic reactions to many of the same triggers that bother humans: pollen, grass, mold, mildew, and dust mites. These environmental allergies (called atopic dermatitis or atopy) can cause sneezing, coughing, wheezing, and watery discharge from the eyes or nose. Unlike a viral infection, allergic sneezing tends to follow a seasonal pattern or flare up in specific environments rather than arriving all at once with a fever.
Non-allergic irritants can also set off sneezing fits. Strong cleaning products, scented candles, cigarette smoke, dusty cat litter, and aerosol sprays are common culprits. If your cat’s sneezing started after you changed litter brands, used a new household product, or opened windows during high-pollen season, an environmental trigger is worth considering. The sneezing usually improves once the irritant is removed.
Something Stuck in the Nose
Foreign objects in the nasal passage cause a sudden, dramatic onset of sneezing that often looks violent and doesn’t let up. Grass blades and grass awns are the most commonly reported foreign bodies in cats. A blade of grass can get lodged after a cat sniffs around outdoors, or even travel up from the back of the throat during vomiting or regurgitation.
The key difference from an infection is the timing: foreign body sneezing starts abruptly and is often one-sided, with discharge coming from just one nostril. As inflammation builds around the object, you may also notice your cat pawing at their nose, breathing with their mouth open, making a snoring or snorting sound, or developing bad breath. This won’t resolve on its own. The object needs to be located and removed by a vet, usually under sedation.
Dental Disease
This one surprises most cat owners. The roots of a cat’s upper teeth sit very close to the nasal cavity, separated by only a thin layer of bone. When a tooth root becomes infected or abscessed, the infection can erode through that bone and create a direct channel into the nose. The result is chronic sneezing, nasal discharge (sometimes from one side), and occasionally a foul smell. If your cat has been sneezing persistently and also has bad breath, difficulty eating, or visible tartar buildup, a dental problem could be the underlying cause.
Nasal Polyps and Growths
Inflammatory polyps are benign growths that can develop in a cat’s nasal passages or the back of the throat. They’re more common in younger cats and kittens. Symptoms include sneezing, a snoring or rattling sound when breathing, nasal discharge, and sometimes difficulty swallowing that leads to weight loss. If a polyp extends into the ear, you might notice head shaking, a head tilt, or balance problems.
Nasal tumors are less common but more serious, and they tend to affect older cats. The signs overlap with polyps (sneezing, discharge, noisy breathing) but may also include nosebleeds and visible swelling or asymmetry of the face. Any cat with persistent one-sided nasal discharge, especially if it’s bloody, needs veterinary evaluation to rule out a growth.
How to Read the Symptoms
The pattern of your cat’s sneezing and what comes with it tells you a lot about the cause:
- Sudden onset with fever, eye discharge, and lethargy points toward a viral upper respiratory infection.
- Seasonal or environment-linked sneezing with clear, watery discharge suggests allergies or irritants.
- Abrupt, violent sneezing with pawing at the nose and one-sided discharge raises suspicion for a foreign object.
- Chronic sneezing with bad breath or eating difficulty may indicate dental disease.
- Persistent sneezing with noisy breathing or nosebleeds warrants investigation for polyps or tumors.
A few episodes of sneezing in an otherwise healthy, active cat that’s eating normally is rarely an emergency. Dust, a whiff of perfume, or a mild irritant can trigger a brief sneezing fit that resolves on its own. What changes the picture is when sneezing persists for more than a day or two, or when it’s accompanied by other signs.
Signs That Need Prompt Attention
Green or yellow nasal discharge signals a bacterial infection, either as the primary problem or layered on top of a viral one. This typically needs treatment. Bloody discharge from one or both nostrils, especially in an older cat, should be evaluated quickly. If your cat stops eating for more than 24 hours, that alone warrants a vet visit, since cats who can’t smell their food often refuse to eat, and prolonged fasting can cause liver problems in cats faster than in most animals.
Breathing through the mouth, shallow or labored breathing, and an inability to sleep in a normal position are more urgent signs that the airways are significantly compromised. A cat that extends its head and neck forward while breathing is working harder than normal to get air in, and this combination of sneezing plus breathing difficulty needs same-day veterinary attention.