Why Is My Cat Sneezing? Harmless Tickle vs. Time to Call the Vet

An occasional sneeze from a cat is as unremarkable as it is from a person — dust, a strong smell, a stray bit of litter. What matters is the pattern. Sneezing that repeats over days, or arrives with discharge from the eyes or nose, is one of the most common reasons cats are seen by a vet, and the underlying causes are worth understanding.

The single most common cause

Feline upper respiratory infection is by a wide margin the usual explanation for a sneezing cat. Veterinary sources describe it as a complex rather than a single disease, because several different pathogens produce a near-identical picture.

The main players are feline herpesvirus-1 and feline calicivirus, which together account for the large majority of cases, alongside bacteria including Chlamydophila felis, Mycoplasma species and Bordetella bronchiseptica. Because the signs overlap so heavily, a vet generally cannot tell them apart by looking — which matters less than it sounds, because the supportive treatment is similar for most.

Typical signs go well beyond sneezing: clear or coloured discharge from the eyes or nose, conjunctivitis with swelling of the membranes around the eyes, coughing, mouth ulcers, lethargy and loss of appetite. A cat showing several of those has a respiratory infection until proven otherwise.

Why herpesvirus matters more than most owners realise

Feline herpesvirus is worth singling out because it does not leave. After the initial infection, the virus persists for life in a latent state in most cats, and it can reactivate during periods of stress — a house move, a new pet, boarding, illness, or any significant change in routine.

That explains a pattern owners find baffling: a cat that seems perfectly well for months and then has a bout of sneezing and runny eyes for a week or two, apparently out of nowhere. It is usually not a new infection. It is the existing one waking up, and reducing stress genuinely reduces the frequency of flare-ups.

The other causes worth knowing

• Irritants. Dust, aerosol sprays, perfume, cigarette smoke, cleaning products, scented candles and dusty cat litter all trigger sneezing. This is the easiest cause to test — change one thing and watch.
• Dental disease. The roots of the upper teeth sit very close to the nasal passages. An infected tooth root can produce persistent sneezing and one-sided nasal discharge, and it is a genuinely under-recognised cause.
• Foreign material. A grass seed or blade of grass lodged in the nasal passage or the back of the throat causes sudden, violent, repeated sneezing that starts abruptly in a previously well cat.
• Nasopharyngeal polyps. Benign growths that can obstruct the nasal passage and cause chronic signs, more common in young cats and often accompanied by noisy breathing.
• Chronic rhinitis. Permanent damage to the delicate structures inside the nose from an earlier severe infection, leaving a cat with lifelong intermittent sneezing and discharge even though the original infection has cleared.
• Fungal infection and, rarely, nasal tumours — more likely in older cats with persistent one-sided signs.

One side or both?

This is the most useful single observation you can make, and it is one a vet will ask about immediately.

Discharge from both nostrils points toward infection or a generalised irritant — something affecting the whole respiratory tract. Discharge from one nostril only points toward a local problem: a foreign body, a tooth root abscess, a polyp or a mass. One-sided signs in an older cat that persist are the combination that most warrants prompt investigation.

When to see a vet

A single sneezing fit in a bright, hungry cat can reasonably be watched for a day or two. Beyond that, most sneezing cats benefit from being seen — partly because supportive care shortens the misery, and partly because the causes that need specific treatment are not distinguishable at home.

Prevention and living with it

Core vaccination covers feline herpesvirus and calicivirus. It does not reliably prevent infection outright, but it substantially reduces how severe the disease is — which is the realistic goal with these viruses rather than complete protection.

For a cat that already carries herpesvirus, the practical work is stress management: predictable routine, enough litter trays and feeding stations in a multi-cat household, vertical space, and a calm introduction plan for any new animal. Some cats benefit from lysine supplementation, though the evidence for it is genuinely mixed and it is worth discussing with your vet rather than assuming. Cats with permanent nasal damage may need periodic courses of treatment for the rest of their lives, and that is a manageable outcome rather than a bleak one.