Feline Herpes in Cats: Symptoms, Eyes, and Kittens

Name: Feline Herpes in Cats: Symptoms, Eyes, and Kittens
Creator: Dr. Zubair Khalid

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-10-02

Feline herpes in cats symptoms usually start as sneezing, clear or colored eye and nose discharge, and red, squinting eyes. Most cats improve with supportive care, but the virus stays in the body for life and can flare up again during stress or illness. Knowing the early signs matters most in kittens, whose small bodies and immature immune systems make them more vulnerable.

This article is educational and is not a substitute for veterinary diagnosis or treatment.

Quick Answer

Feline herpesvirus type 1 (FHV-1) is a common cause of upper respiratory and eye disease in cats, and it spreads through direct or indirect contact with an infected cat's secretions [1].
The most common signs are sneezing, nasal discharge, eye discharge, conjunctivitis, and fever [2].
Kittens and young cats are hit hardest, and the virus can cause serious eye damage if it goes untreated.
About 80% of infected cats become lifelong carriers, so symptoms can return during stress, illness, or other triggers [1].
Any kitten with a closed, swollen, or cloudy eye needs to see a veterinarian the same day.

What Is Feline Herpesvirus in Cats?

Feline herpesvirus type 1 is a virus that infects cats and only cats. It causes feline viral rhinotracheitis, an infection of the nose, throat, and upper airways, and it also attacks the tissues around and inside the eye [2][1]. The virus is a local contact pathogen, meaning it spreads when a cat touches infected secretions, not through the air over long distances [3].

Once a cat is infected, the virus does not leave. It hides in nerve tissue and stays quiet until something wakes it up. Around 80% of infected cats establish this lifelong latent infection [1]. That is why a cat who had "a bad cold" as a kitten may sneeze and get goopy eyes again years later after a move, a new pet, or a trip to the vet.

FHV-1 is one of the two main viruses behind respiratory disease in cats, along with feline calicivirus [4]. It is very common. In one regional survey, FHV-1 was found in samples from 55% of tested domestic cats [2]. Infection rates are especially high in young cats, with a clinical incidence rate approaching 100% in that group [3].

Feline Herpes in Cats Symptoms: What Owners Notice First

The first thing most owners see is sneezing. It often comes with a runny nose and watery eyes that look like a common cold. From there, signs can stay mild or escalate quickly.

Early signs of cat herpes

Sneezing, sometimes in bursts [2]
Clear, then cloudy or colored, nasal discharge [2]
Eye discharge, which may start clear and turn thick [2]
Red, swollen conjunctiva (the pink tissue around the eye) [2]
Squinting, blinking, or holding one eye partly shut
Fever and a general "not feeling well" look [2]
Reduced appetite and less interest in play

Signs that show up as the illness progresses

Cough [2]
Nasal congestion that makes breathing sound noisy
Mouth breathing in severe cases
Corneal ulcers, which look like a cloudy or blue spot on the eye surface [5]
Dendritic ulcers, a branching pattern of damage on the cornea [5]

The pattern matters. Signs tend to be worst about 9 to 13 days after they start and then ease over 2 to 3 weeks [6]. Some cats, though, keep showing signs for weeks even with treatment, and flare-ups are common [6].

Feline herpes in cats eyes

Eye involvement is where this virus does its most lasting damage. FHV-1 can cause conjunctivitis, corneal ulcers, and in severe cases damage that threatens vision [5][1]. A cat with herpes eye disease often squints, tears heavily, and develops a cloudy spot on the cornea. The discharge may be clear at first and become thick and yellow-green as secondary bacteria move in.

If your cat has eye discharge, our guide on Why Is My Cat having eye discharge? Herpesvirus Chlamydia and Conjunctivitis walks through how herpes and other causes compare.

One important caution: never use leftover steroid eye drops on a cat with a red or cloudy eye. Steroids can make a herpes ulcer much worse. In one report, two kittens given corticosteroid eye drops after vaccination went on to develop dendritic ulcers and corneal ulcers [5].

Feline Herpes in Kittens

Kittens are the group you worry about most. Their immune systems are still developing, their airways are tiny, and they dehydrate fast when they stop eating and drinking.

Feline herpes kittens symptoms

Kitten signs look like adult signs but tend to be more intense:

Sneezing and thick nasal discharge
Eyes stuck shut with crusts, often both eyes
Swollen, red conjunctiva
Cloudy or ulcerated cornea [5]
Fever, weakness, and poor nursing
Weight loss or failure to gain weight

In one case report, two 2-month-old littermates developed sneezing and eye discharge within days of a modified live virus vaccination, and both went on to develop corneal ulcers [5]. That does not mean vaccines are unsafe. It means young kittens can have strong reactions, and any kitten with eye signs after a vaccine should be seen promptly.

Kittens can also pick up the virus from their mother during birth or in the first weeks of life. Because the virus spreads through direct and indirect contact with secretions, a carrier mother grooming or nursing her kittens can pass it along [1].

If your kitten has a swollen eye, a cloudy eye, or will not eat, treat it as urgent. Eye damage in kittens can move fast.

What Causes Feline Herpes in Cats?

The cause is infection with feline herpesvirus type 1. There is no other trigger that creates the virus. What varies is how a cat gets exposed and what makes symptoms appear later.

How it spreads

Direct contact with an infected cat's eye, nose, or mouth secretions [1]
Indirect contact through shared bowls, bedding, toys, or human hands and clothing [1]
Mother to kitten during birth or early nursing

The virus does not survive long in the environment, but it does not need to. Close contact in a multi-cat home, shelter, or cattery is enough.

What wakes the virus up

After the initial infection, the virus stays latent. Reactivation is often linked to stress or a dip in immune function. Common triggers include:

Moving to a new home
A new pet or a new baby
Boarding or a shelter stay
Other illness, including retroviral infections
Surgery or anesthesia
Pregnancy and nursing

Co-infection with feline leukemia virus or feline immunodeficiency virus makes respiratory disease worse. In one pathology study of cats that died with respiratory disease, 14 of 22 virus-positive cats also had FeLV, FIV, or both [4]. If your cat has repeated herpes flare-ups, your veterinarian may suggest testing for these viruses.

How Feline Herpes Is Diagnosed

Your veterinarian starts with the history and a physical exam, then looks closely at the eyes and nose. A few tests can confirm the diagnosis or rule out look-alikes.

Test	What it looks for	Notes
Physical and eye exam	Sneezing, discharge, conjunctivitis, corneal ulcers	First step in every case [2]
Fluorescein stain	Corneal ulcers	Detects damage that is not visible to the eye alone
PCR on swabs	FHV-1 DNA from eye, nose, or throat samples	Used in clinical studies to confirm active infection [2][7]
Rapid antigen test	FHV-1 antigen from nasopharyngeal or fecal samples	Results in about 10 minutes in a research setting [3]
Blood antibody test	Neutralizing antibodies to FHV-1	Shows exposure, not always active disease [1][8]

A positive test does not always mean the virus is the current problem, because many healthy cats carry it. Your veterinarian puts the test result together with the signs your cat is showing.

Other conditions can look similar. Chlamydial conjunctivitis causes eye and nose discharge and sneezing, mostly in cats under a year old, and signs peak 9 to 13 days after onset [6]. Calicivirus is the other major respiratory virus in cats [4]. Sorting these out changes treatment, so testing has real value.

Treatment Options for Feline Herpes

There is no cure that removes the virus. Treatment aims to shorten the flare, ease discomfort, protect the eyes, and support eating and drinking.

Antiviral medication

Antivirals are the mainstay for active infection. In one clinical study, cats with confirmed FHV-1 infection were treated with a combination of oral famciclovir and L-lysine, ophthalmic acyclovir, and subcutaneous amoxicillin plus clavulanic acid. Symptoms improved each day, with an 80% reduction in clinical scores by day 10 [7].

Your veterinarian calculates every dose from your cat's weight, kidney and liver health, and the severity of the flare. Do not use a dose from the internet or from a previous prescription.

Supportive care at home

Keep the nose and eyes clean with warm, damp cotton pads
Run a humidifier or take your cat into a steamy bathroom to loosen congestion
Offer warmed, smelly food to tempt a stuffed-up cat
Keep water close by and consider a fountain
Reduce stress where you can

Eye treatment

Eye care depends on what the exam shows. A simple conjunctivitis is treated differently from a corneal ulcer. Some cats need antibiotic drops for secondary bacteria, some need antiviral drops, and some need lubricating drops to protect the surface. In the case report above, kittens with corneal ulcers were treated with oral antiviral medication and hyaluronic acid eye drops [5].

Never start or stop eye medication without a recheck. Ulcers can worsen quickly if the wrong drop is used.

Recovery, Outlook, and Long-Term Management

Most cats recover from an acute flare in 2 to 3 weeks, though some take longer and some have recurring signs even with treatment [6]. The 80% improvement seen by day 10 in the combination treatment study shows that good results are possible with consistent care [7].

The long-term reality is that your cat remains a carrier. Around 80% of infected cats keep the virus for life [1]. That means you should expect occasional flare-ups, especially during stressful events.

What helps long term

Keep stress low and routines predictable
Maintain regular veterinary checkups, including eye exams
Stay current on core vaccines as your veterinarian advises
Treat other illnesses promptly
Watch for early signs so you can start treatment fast

If your cat has repeated urinary or litter box issues alongside herpes flares, stress can play a role in both. Our articles on What Are Symptoms Of A Uti In A Cat and Symptoms Of Urinary Infection Cats cover what to watch for.

Prevention

You cannot fully prevent herpes in a cat who is already infected, but you can lower the odds of new infections and reduce flare-ups.

Vaccinate. FHV-1 modified live vaccine is a core vaccine for cats [5]. Vaccination reduces the severity of disease, though individual cats vary in how much protective antibody they develop [1].
Limit contact with unknown cats, especially in shelters or boarding facilities.
Wash bowls, bedding, and toys regularly, and wash your hands between cats.
Isolate a new cat for a couple of weeks before introductions.
Keep kittens away from sick cats and crowded environments until they are fully vaccinated.
Manage stress during moves, travel, and household changes.

One study found that neutralizing antibodies were uncommon in both vaccinated and unvaccinated cats in a sampled population, and seropositivity was not linked to vaccination status [8]. That does not mean vaccines fail. It means immunity is individual, and vaccination is one layer of protection among several.

Limitations and When to Contact a Veterinarian

This article covers general patterns. Your cat's case needs a veterinarian who can examine the eyes, test for ulcers, and choose treatment based on what is actually happening.

Contact a veterinarian the same day if you see

A kitten with any eye swelling, cloudiness, or stuck-shut eyes
A cat squinting or holding one eye closed
A cloudy, blue, or white spot on the cornea
Thick yellow or green eye or nose discharge
Refusing food for more than 24 hours
Fever, lethargy, or hiding

Go to an emergency clinic now if you see

Open-mouth breathing or obvious trouble breathing
A sudden collapse or extreme weakness
A bulging eye or a eye that looks ruptured
A kitten who is limp, cold, or unresponsive

Schedule a routine visit if you see

Mild sneezing that lasts more than a few days
Clear eye discharge that comes and goes
Repeated flare-ups after stressful events
Any cat with a history of herpes who seems "off"

Frequently Asked Questions

Can feline herpes go away on its own?

Mild flares often ease over 2 to 3 weeks with supportive care, but the virus itself never leaves the body. Treatment shortens the flare and protects the eyes from lasting damage. Kittens and cats with eye involvement should always be seen by a veterinarian.

Is feline herpes contagious to humans or dogs?

No. Feline herpesvirus type 1 infects cats only. It does not spread to people, dogs, or other species. Your other cats are the ones at risk, so separate a sick cat from the rest of the household during a flare.

Can my cat get herpes again after recovering?

Yes. The virus stays hidden in nerve tissue and can reactivate during stress, illness, or other immune challenges. Most infected cats carry it for life, so repeat flares are expected. Good stress management and prompt treatment at the first sign help keep flares short.

Do I need to treat a herpes flare if my cat seems fine?

If your cat is eating, playing, and has clear eyes, a mild sneeze may not need medication. Any change in the eyes, appetite, or breathing does need a vet visit. When in doubt, a quick exam is cheaper than treating a corneal ulcer later.

Should I keep my cat away from other cats during a flare?

Yes. During an active flare, your cat sheds virus in eye and nose secretions and can infect other cats through direct or indirect contact. Keep food bowls, bedding, and litter boxes separate, and wash your hands between cats. Ask your veterinarian when it is safe to reintroduce them.

References

Detection of neutralizing antibody to Feline herpesvirus type 1 in cat serum. Comparative immunology, microbiology and infectious diseases, 2025.
Frequency of feline herpesvirus 1 (FHV-1) in domestic cats from Campo Grande, MS, Brazil. Anais da Academia Brasileira de Ciencias, 2023.
Rapid and sensitive detection of feline herpesvirus-1 using fluorescent microspheres as labels for immunochromatographic test strips. Veterinary research communications, 2026.
Feline herpesvirus and calicivirus: Occurrence and pathology in cats with respiratory disease. Topics in companion animal medicine, 2025.
Corneal Lesions Associated With Feline Herpesvirus-1 Modified Live Vaccine Strain F2 in Two Cats. Case reports in veterinary medicine, 2026.
Chlamydial Conjunctivitis in Cats (Feline Pneumonitis) - Cat Owners. Merck Veterinary Manual.
Clinical evaluation of antiviral combination treatment in cats with feline herpesvirus-1 infection. Polish journal of veterinary sciences, 2023.
Tracing feline herpesvirus-1 exposure in domestic cats from Namibia: associations with neutralising antibodies, vaccination, clinical signs, and retroviral status. Veterinary research communications, 2026.