Why Is My Cat Sneezing? Causes and When to See a Vet

When a sneeze is worth a second look

Most sneezes are just a reflex: something irritates the nose and a burst of air clears it. A bit of dust, a stray grain of litter, a whisker, a puff of perfume can all set one off. A cat who sneezes once or twice and goes back to grooming and napping is usually fine.

Pay attention when sneezing repeats over several days, comes in rapid fits, or arrives with a runny nose, watery or crusty eyes, less interest in food, or low energy. A sneeze on its own is rarely the story. A sneeze plus a snotty nose plus a skipped breakfast is.

Cat flu: the most common cause

When sneezing won’t quit, the usual culprit is an upper respiratory infection (URI), often called “cat flu.” It is one of the most common illnesses in cats and spreads easily wherever cats live close together, from shelters and foster homes to catteries and multi-cat households. Plenty of cats arrive home already infected.

Two viruses account for the large majority of cases.

Feline herpesvirus (FHV-1)

A first infection brings sneezing fits, a runny nose, conjunctivitis, and often a fever and poor appetite. Most cats who recover keep the virus for life. It lies dormant and flares back up at times of stress, such as a house move, a new pet, boarding, or another illness, so a cat can start sneezing again years after the original infection with no new cat anywhere in sight.

Feline calicivirus (FCV)

FCV causes sneezing and nasal discharge too, and it is best known for mouth ulcers, painful sores on the tongue or gums that lead to drooling and a reluctance to eat. Some strains also cause a temporary limping in kittens. Like herpesvirus, infected cats can keep shedding the virus for weeks or months after they look recovered.

When bacteria get involved

Bacteria such as Chlamydia felis, Bordetella, and Mycoplasma can cause respiratory infection on their own, and conjunctivitis is usually the most obvious sign. More often, bacteria move in as a second wave on top of a viral infection. That secondary infection is often what turns thin, clear nasal discharge into something thick and yellow or green, though a heavy viral infection can sometimes do the same.

Why an indoor-only cat can still get cat flu

Many cats pick up herpesvirus as kittens, which is very common in litters and shelters, and carry it for good. A flare-up needs no outside contact: stress lowers the immune system’s guard and the dormant virus reactivates. So a single indoor-only cat is unlikely to catch a new infection, but an old one can still come back.

Other reasons a cat sneezes

Sneezing isn’t always cat flu. Inhaled irritants, a foreign body up the nose, dental disease, and nasal polyps or tumors can all cause it.

Inhaled irritants are the least worrying. Switching to a low-dust litter and going easy on sprays and smoke near your cat usually solves it. A foreign body, often a blade of grass or a seed, is more urgent: the sneezing is sudden, frantic, and won’t let up, and a vet needs to find and remove it.

The roots of the upper teeth sit right below the nasal cavity, so a severe dental infection can break through and cause chronic sneezing. In an older cat, sneezing that slowly worsens on one side, especially with blood or a change in face shape, should be checked promptly, since nasal polyps and tumors become more likely with age. If snoring starts at the same time, see the snoring guide.

What to watch alongside the sneezing

Start with the nose. Thin, clear discharge usually means a viral infection or simple irritation. Thick, yellow, or green discharge suggests bacteria have joined in. Any blood is a reason to call a vet sooner rather than later.

Then the eyes. Watery eyes, redness, squinting, or an eye that is partly or fully shut can mean conjunctivitis or, more seriously, a corneal ulcer from herpesvirus. Eye problems in cats can move fast, so they should not wait.

Watch breathing and energy too. A cat who is breathing hard, breathing through an open mouth, or visibly heaving the belly is an emergency that can’t wait until morning. A cat who suddenly withdraws, hides, and stops doing normal things needs attention as well. And watch appetite closely; it is the sign that matters most.

When to see a vet

Most mild cat flu can be managed at home, much the way you would ride out a head cold. But some signs mean it is time for a professional.

Beyond appetite, get your cat seen if you notice any of these:

• Labored or open-mouth breathing
• Thick yellow or green discharge, or any blood
• An eye that is swollen, squeezed shut, or has a visible ulcer
• Sneezing that drags on beyond 7 to 10 days, or keeps coming back
• Lethargy, hiding, or a cat that simply is not itself
• A kitten with any of the above, since kittens go downhill quickly

Home care while your cat recovers

For a mild case, the job is to keep your cat comfortable and eating while the immune system does the real work.

Steam helps. Bring your cat into the bathroom while you run a hot shower for ten or fifteen minutes, and the humidity loosens congestion and makes breathing easier. Between those sessions, wipe any discharge from the nose and eyes with a soft cloth and warm water, since a crusted-over nose is uncomfortable and harder to breathe through.

Eating matters most. A cat who can’t smell the meal often won’t touch it, so warm wet food slightly to bring out the aroma and offer the strongest-smelling food you have. Keep water within easy reach too, because congestion and a mild fever both push a cat toward dehydration; the hydration guide has more ideas.

Give your cat a warm, quiet place to rest, which helps recovery and makes a drawn-out herpesvirus flare less likely. Cat flu spreads easily between cats, so keep a sneezing cat away from the others until he’s better.

How a vet treats it

Most viral cat flu clears up on its own. Uncomplicated cases usually run one to two weeks, though some drag on or flare up again. No drug clears these viruses from the body, so treatment is about supporting the cat while the immune system fights them.

A vet may prescribe antibiotics when bacteria are suspected, but antibiotics do nothing against the viruses themselves. For severe herpesvirus cases, particularly when the eyes are badly affected, a vet may add an antiviral, along with eye medication for conjunctivitis or corneal ulcers.

Many owners buy L-lysine. It was a standard recommendation for herpesvirus for years, and it’s still on shelves and in articles, but reviews of the research found that lysine supplements don’t prevent or reduce herpesvirus infection in cats, and it is no longer recommended. Put that money and effort into reducing stress and keeping your cat eating instead.

Reducing the risk

You can’t make a cat sneeze-proof, but you can make illness less frequent and less severe.

The core FVRCP vaccine covers both herpesvirus and calicivirus. A vaccinated cat can still be infected, and a cat who already carries the virus still will, but episodes become less frequent and less severe, which is why it is a core vaccine for every cat.

Keep everyday stress low, since stress is the main trigger for herpesvirus flares, and use a low-dust litter to spare the airways.

When a new cat joins the household, keep the cats apart for about two weeks before introductions, so an infection the new cat is already carrying has time to show. If cat flu is already in the house, wash shared bowls and bedding often, since the viruses spread on objects as well as through direct contact.

How Furwise Can Help

Sneezing changes day to day, and it’s much easier to describe at the vet if you’ve written it down. Furwise lets you log symptoms with photos of nose and eye discharge, and record how much your cat ate and how the appetite was. When the vet asks how long, how often, and whether it’s getting better or worse, the answers are in the log.

An occasional sneeze is nothing to worry about. Frequent sneezing with a runny nose, eye discharge, or a dip in appetite usually means cat flu, and most cases clear up with rest, steam, and a little patience. Appetite matters most: a cat who keeps eating can usually be nursed at home, and a cat who stops needs a vet promptly. When you’re unsure, go by the color of the discharge and your cat’s energy.

Frequently Asked Questions

Why does my cat keep sneezing? Repeated sneezing over several days is most often a sign of an upper respiratory infection, or “cat flu,” usually caused by feline herpesvirus or calicivirus. Other causes include inhaled irritants, a foreign object lodged in the nose, dental disease, and, in older cats, nasal polyps or tumors. If the sneezing comes with a runny nose, eye discharge, or appetite loss, have a vet take a look.

Is cat sneezing contagious to humans? No. The viruses behind cat flu, feline herpesvirus and feline calicivirus, are specific to cats and do not infect people. They are, however, very contagious between cats, so a sneezing cat should be kept apart from other cats in the home. Washing your hands after handling a sick cat is still a sensible habit.

Can I give my cat human cold medicine? No. Never give human cold or flu medication to a cat. Common ingredients such as acetaminophen (paracetamol) and decongestants are toxic to cats and can be dangerous even in small doses. Stick to vet-guided care for anything beyond basic home support.

Can allergies make a cat sneeze? Not as often as people assume. Unlike people, cats with allergies usually get itchy skin. Repeated sneezing is far more likely to come from an infection or an irritant such as dusty litter or aerosol sprays.

When should I take my sneezing cat to the vet? See a vet if your cat stops eating, breathes with effort or an open mouth, has thick yellow or green or bloody discharge, has a swollen or shut eye, or keeps sneezing beyond 7 to 10 days. Kittens and any cat that seems lethargic or unwell should be seen sooner rather than later.

Does L-lysine help cats with herpesvirus? No. L-lysine was recommended for years and is still widely sold, but research reviews found it doesn’t prevent or reduce herpesvirus infection in cats. Reducing stress and keeping your cat eating well help more.