Cat Conjunctivitis: Pink Eye Causes, Treatment & Home Care

Last updated: March 26, 2026

If your cat is squinting, pawing at a watery or crusty eye, or you have noticed the tissue around one or both eyes turning pink or red, there is a strong chance you are looking at cat conjunctivitis. It is one of the most frequently diagnosed eye conditions in felines, and it affects cats of every age and breed. While a mild case may look like nothing more than a weepy eye, conjunctivitis can signal an underlying infection that needs veterinary treatment — and in some cases, it can become chronic if not addressed properly. This comprehensive guide walks you through every aspect of pink eye in cats, from the root causes to safe home care practices, so you can help your cat recover quickly and comfortably.

What Is Conjunctivitis in Cats?

Conjunctivitis is the inflammation of the conjunctiva, the thin, transparent mucous membrane that lines the inner surface of the eyelids and covers the front of the eyeball up to the edge of the cornea. In a healthy cat, the conjunctiva is barely visible. When it becomes inflamed, the tissue swells, reddens, and often produces discharge — giving the eye that characteristic pink or red appearance that earns the condition its common name, pink eye.

Cat conjunctivitis can affect one eye (unilateral) or both eyes (bilateral). Whether one or both eyes are involved often provides a useful clue about the underlying cause. Viral and bacterial infections tend to affect both eyes, while a foreign body, injury, or localized irritation may only involve one. The condition can be acute — appearing suddenly and resolving with treatment — or chronic, persisting or recurring over weeks, months, or even years in some cats.

Conjunctivitis itself is not a disease but a symptom. It tells you that something is irritating or infecting the eye, and the priority is identifying what that something is so the correct treatment can begin. Left untreated, cat conjunctivitis can progress from a mild irritation to corneal ulceration, scarring, and permanent damage to vision — making early veterinary attention essential.

Causes of Cat Conjunctivitis

Understanding the cause behind your cat’s pink eye is critical because different causes require different treatments. An antibiotic drop will do nothing against a virus, and an antiviral will not resolve a bacterial infection. Here are the most common culprits behind cat conjunctivitis.

Feline herpesvirus (FHV-1): Feline herpesvirus type 1 is the single most common cause of conjunctivitis in cats. It is estimated that the vast majority of cats are exposed to FHV-1 at some point in their lives, and once infected, a cat carries the virus for life. The virus lies dormant in the nerve cells and can reactivate during periods of stress, illness, or immune suppression — triggering a fresh episode of conjunctivitis. FHV-1-related conjunctivitis typically presents with both eyes affected, along with sneezing, nasal discharge, and general upper respiratory signs. Kittens and cats in shelters or multi-cat households are especially vulnerable. Because the virus can never be fully eliminated from the body, cats with herpesvirus-related conjunctivitis may experience recurring flare-ups throughout their lives.

Chlamydia felis: Chlamydia felis is an intracellular bacterium and the second most common infectious cause of cat conjunctivitis. It typically begins in one eye before spreading to the other within a few days. The discharge is often thick, yellowish, and mucopurulent, and the conjunctival swelling can be dramatic — sometimes causing the tissue to protrude visibly from the eye. Chlamydial conjunctivitis is most common in young cats and in environments where cats live in close quarters, such as catteries and shelters. It responds well to appropriate antibiotic therapy, particularly tetracyclines.

Other bacterial infections: Beyond chlamydia, a range of other bacteria — including Staphylococcus, Streptococcus, and Mycoplasma species — can cause or complicate cat conjunctivitis. Bacterial conjunctivitis may arise as a primary infection, but it frequently develops as a secondary infection on top of viral damage. When herpesvirus weakens the eye’s natural defenses, opportunistic bacteria move in and make the situation worse. Bacterial cases tend to produce thick, yellow or green discharge and may cause the eyelids to stick together, particularly after sleep.

Allergies and environmental irritants: Cats can develop allergic conjunctivitis in response to pollen, dust, mold spores, cigarette smoke, household cleaning products, perfumes, or other airborne irritants. Allergic conjunctivitis usually affects both eyes simultaneously and produces a clear, watery discharge rather than the thick, colored discharge seen in bacterial infections. The cat may also show other allergic signs such as sneezing, itchy skin, or excessive grooming. Unlike infectious causes, allergic conjunctivitis is not contagious but may recur seasonally or whenever the cat encounters the triggering allergen.

Other causes: Less common causes of conjunctivitis in cats include foreign bodies trapped under the eyelid, physical trauma or scratches to the eye, entropion (inward rolling of the eyelid), blocked tear ducts, and — rarely — tumors or growths on the conjunctival tissue. Certain breeds with prominent eyes or flat faces, like Persians and Himalayans, may be predisposed to chronic eye problems. If you are curious about breed-specific health traits, our cat breeds directory is a helpful starting point.

Symptoms of Cat Conjunctivitis

Recognizing the symptoms of cat conjunctivitis early gives your cat the best chance of a quick, uncomplicated recovery. Here is what to watch for.

Redness: The white of the eye and the inner eyelid tissue appear visibly pink, red, or inflamed. This is often the most obvious sign and the one owners notice first.

Discharge: Eye discharge is almost always present. It can range from clear and watery (common with viral or allergic causes) to thick, yellow, green, or crusty (indicating bacterial involvement). The discharge may mat the fur around the eye and cause the eyelids to stick shut after the cat sleeps.

Squinting and blinking: A cat with conjunctivitis will often squint or hold the affected eye partially closed. Excessive blinking, frequent pawing at the eye, and rubbing the face against furniture or carpet are also common.

Swelling: The conjunctival tissue can become visibly swollen, and the eyelids themselves may appear puffy. In severe cases — particularly with chlamydial infections — the swollen conjunctiva may protrude from the eye opening, a condition called chemosis.

Third eyelid elevation: Cats have a third eyelid, or nictitating membrane, located at the inner corner of each eye. When the eye is irritated or inflamed, this membrane often rises and becomes partially visible, giving the eye a hooded or covered appearance.

Behavioral changes: Your cat may become more withdrawn, avoid bright light (photophobia), eat less, or seem generally uncomfortable. Cats in pain tend to hide — if your usually social cat is spending more time under the bed, a painful eye condition could be the reason.

How Veterinarians Diagnose Cat Conjunctivitis

A thorough ophthalmic examination is essential to determine the cause of cat conjunctivitis and rule out more serious conditions. Your veterinarian will begin with a visual inspection of the eye using an ophthalmoscope, checking the conjunctiva, cornea, iris, and surrounding structures for abnormalities.

A fluorescein stain test is frequently performed. A drop of orange-green dye is applied to the eye’s surface; if a corneal ulcer is present, the dye will adhere to the damaged area and glow under a special light. This test is important because corneal ulcers — which can be caused by herpesvirus or scratching — require additional treatment beyond what standard conjunctivitis care provides.

The Schirmer tear test measures tear production to rule out dry eye (keratoconjunctivitis sicca), which can mimic or contribute to conjunctivitis. Swabs of the conjunctival discharge may be collected and sent for bacterial culture, sensitivity testing, or PCR testing to identify specific infectious agents like herpesvirus or chlamydia. Tonometry — measuring the pressure inside the eye — may be performed to rule out glaucoma, which can present with similar signs of redness and discomfort.

Treatment for Cat Conjunctivitis

Treatment for cat conjunctivitis depends entirely on the underlying cause. There is no single eye drop that works for every case, which is why a veterinary diagnosis is so important before beginning any medication.

Antibiotic eye drops and ointments: If bacteria — including Chlamydia felis — are identified or suspected as the cause, your veterinarian will prescribe topical antibiotic drops or ointment. Common choices include chloramphenicol, fusidic acid, and oxytetracycline. For chlamydial infections specifically, systemic antibiotics such as doxycycline may be prescribed alongside topical treatment for a course of three to four weeks. It is critical to complete the entire prescribed course, even if the eye looks better within a few days, to prevent recurrence and antibiotic resistance.

Antiviral medications: When feline herpesvirus is the cause, antiviral eye drops or ointments are the frontline treatment. Idoxuridine, cidofovir, and trifluridine are topical antivirals used in veterinary ophthalmology. In some cases, the oral antiviral famciclovir may be prescribed, particularly for severe or recurrent herpesvirus flare-ups. L-lysine supplementation was once widely recommended as an antiviral support, but more recent veterinary research has cast doubt on its effectiveness — discuss its use with your veterinarian before adding it to your cat’s regimen.

Anti-inflammatory and supportive treatments: Non-steroidal anti-inflammatory eye drops may be used to reduce swelling and discomfort. However, corticosteroid eye drops — while effective at reducing inflammation — must be used with extreme caution in cats because they can worsen herpesvirus infections and delay healing of corneal ulcers. Your veterinarian will only use steroids after confirming there is no viral cause and no corneal damage present.

Treatment for allergic conjunctivitis: When allergies are the cause, the primary goal is identifying and removing the allergen. Antihistamine eye drops, environmental modifications, and in some cases systemic antihistamines may be recommended. Air purifiers, switching to unscented litter, and reducing household irritants can all help manage allergic conjunctivitis long-term.

Home Care for a Cat with Conjunctivitis

While veterinary treatment addresses the root cause of cat conjunctivitis, good home care supports healing and keeps your cat comfortable throughout recovery. Here is what you can do at home.

Keep the eyes clean. Gently wipe away discharge from your cat’s eyes using a soft, lint-free cloth or cotton ball dampened with warm (not hot) water. Use a fresh cloth or cotton ball for each eye to avoid spreading infection from one eye to the other. Wipe from the inner corner of the eye outward in a single, gentle stroke. Do this as often as needed throughout the day — typically every few hours if discharge is heavy.

Administer medication as directed. Follow your veterinarian’s instructions for applying eye drops or ointment precisely. If your cat is difficult to medicate, wrap the cat gently in a towel to restrain movement, tilt the head slightly upward, and use one hand to hold the eye open while applying the medication with the other. Avoid touching the dropper tip to the eye surface to prevent contamination. If you are struggling with administration, ask your vet for a demonstration.

Reduce stress. Stress is a major trigger for herpesvirus reactivation, which is the most common cause of recurring cat conjunctivitis. Provide your cat with a quiet, comfortable recovery space away from loud noises, other pets, and household disruption. Maintain consistent feeding and play routines. Pheromone diffusers designed for cats may help reduce anxiety during recovery.

Prevent self-injury. If your cat is scratching or pawing at the eye aggressively, an Elizabethan collar (cone) may be necessary to prevent further damage to the cornea. Your veterinarian can provide an appropriately sized collar.

Monitor progress. Watch for improvement over the first 48 to 72 hours of treatment. The discharge should decrease, redness should begin to fade, and your cat’s comfort level should improve. If there is no improvement — or if symptoms worsen — contact your veterinarian promptly for a reassessment.

Is Cat Conjunctivitis Contagious to Other Cats?

Yes — infectious conjunctivitis caused by feline herpesvirus, chlamydia, or other bacteria is highly contagious between cats. The pathogens spread through direct contact with an infected cat’s eye or nasal discharge, through shared food and water bowls, and through contaminated hands, bedding, or grooming tools. Sneezing can also propel virus-laden droplets to other cats in close proximity.

If you have a multi-cat household and one cat develops conjunctivitis, isolate the affected cat in a separate room with its own litter box, food, water, and bedding. Wash your hands thoroughly with soap and water after handling the infected cat and before touching other cats. Disinfect shared items and surfaces. Keep the infected cat isolated until your veterinarian confirms the infection has resolved.

Allergic and irritant-related conjunctivitis is not contagious. However, if multiple cats in your home develop conjunctivitis simultaneously, it is far more likely to be an infectious cause than an allergic one, and all affected cats should be examined and treated. If you are considering bringing a new cat into your home, be aware that shelter cats frequently carry herpesvirus — our adoption page can guide you through the process of welcoming a new cat responsibly.

Can Humans Get Conjunctivitis from Cats?

The risk is low but not zero. Feline herpesvirus (FHV-1) is species-specific and does not infect humans — you cannot catch herpes-related pink eye from your cat. Standard feline bacterial causes of conjunctivitis are also generally not transmissible to people with healthy immune systems.

The exception is Chlamydia felis. While rare, there have been documented cases of C. felis causing conjunctivitis in humans, particularly in immunocompromised individuals. The risk is considered very low for healthy adults, but it is sensible to take basic precautions: wash your hands after cleaning your cat’s eyes or administering medication, avoid touching your own face before washing up, and supervise children who may handle an infected cat and then rub their own eyes.

If you develop eye redness, discharge, or irritation while caring for a cat with conjunctivitis, see your doctor and mention the cat’s diagnosis. In all likelihood the two events are unrelated, but it is worth reporting.

Chronic and Recurrent Conjunctivitis in Cats

Some cats suffer from conjunctivitis that never fully resolves or that keeps coming back. Chronic conjunctivitis is most often linked to feline herpesvirus, which persists in the body for life and reactivates during periods of stress, illness, or immune suppression. Cats with chronic herpesvirus-related conjunctivitis may have flare-ups triggered by boarding, moving to a new home, introduction of a new pet, veterinary visits, or even seasonal changes.

Managing chronic cat conjunctivitis is about controlling flare-ups rather than curing the underlying infection. Your veterinarian may recommend keeping antiviral eye drops on hand to start treatment at the earliest sign of a recurrence. Long-term strategies include minimizing environmental stress, maintaining excellent nutrition to support immune function, and keeping the cat’s living area clean and free of respiratory irritants.

In some cases, chronic conjunctivitis results from structural problems like entropion, where the eyelid rolls inward and the eyelashes continuously irritate the conjunctiva and cornea. This requires surgical correction. Persistent dry eye is another cause of chronic inflammation that needs ongoing management with tear-replacement drops and sometimes cyclosporine ointment.

If your cat has been treated for conjunctivitis multiple times without lasting improvement, ask your veterinarian about referral to a veterinary ophthalmologist for a more specialized assessment.

Kittens with Eye Infections

Kittens are particularly vulnerable to conjunctivitis and eye infections. Neonatal kittens — those under two weeks old whose eyes have not yet opened — can develop a condition called ophthalmia neonatorum, where infection builds up behind the closed eyelids, causing visible swelling. This is a veterinary emergency. The eyelids must be gently opened by a veterinarian to drain the infection and allow topical treatment to reach the eye surface. Delayed treatment can result in corneal perforation and permanent blindness.

Kittens born to mothers carrying feline herpesvirus are at high risk of developing conjunctivitis shortly after birth or within the first few weeks of life. Shelter kittens and orphaned kittens raised without maternal antibodies are also highly susceptible. Because a kitten’s immune system is still developing, infections can progress rapidly and cause disproportionately severe damage compared to the same infection in an adult cat.

Signs of eye infection in kittens include crusted-shut eyes, swollen eyelids, pus or discharge visible at the eye margins, and lethargy or failure to thrive. Never attempt to force open a kitten’s eyes at home — this can cause serious injury. Any kitten with visible eye swelling, discharge, or difficulty opening its eyes should be seen by a veterinarian the same day.

If you are adopting or fostering kittens, be prepared for the possibility of eye infections and have a plan in place for prompt veterinary care. Visit our adoption resources to learn more about what to expect when bringing a young cat home.

When to See the Vet Urgently

While many cases of cat conjunctivitis are mild and resolve with routine treatment, certain signs indicate a more serious problem that requires urgent veterinary attention. Do not delay seeking care if you observe any of the following.

Eye is completely shut or glued closed with discharge. This may indicate a severe infection or a corneal ulcer underneath the closed lid. The longer the eye remains shut and untreated, the greater the risk of permanent damage.

Visible cloudiness or color change in the eye. A cloudy, bluish, or white appearance to the normally clear cornea suggests a corneal ulcer or edema — both of which require immediate attention to preserve vision.

Sudden loss of vision or walking into objects. If your cat appears disoriented, bumps into furniture, or shows unequal pupil sizes, this may point to glaucoma, uveitis, or another condition beyond simple conjunctivitis.

Pain signs: crying out, head shaking, extreme squinting. Intense pain suggests possible corneal damage, a foreign body embedded in the eye, or elevated intraocular pressure. These are not situations to monitor at home.

No improvement after 48 to 72 hours of treatment. If prescribed medication is not producing any visible improvement within two to three days, the diagnosis may need revisiting. The wrong medication — an antibiotic when a virus is the cause, for example — will not work no matter how faithfully you apply it.

Conjunctivitis in a very young kitten. Any eye problem in a kitten under eight weeks old warrants same-day veterinary attention due to the speed at which infections can progress and the vulnerability of developing eyes.

When in doubt, err on the side of caution. A brief veterinary visit to confirm that a mild case is truly mild is always preferable to waiting too long on a case that turns out to be serious.

Frequently Asked Questions

How long does cat conjunctivitis take to heal?

With appropriate veterinary treatment, most cases of cat conjunctivitis show noticeable improvement within three to seven days, and many resolve fully within two to three weeks. Bacterial infections treated with the correct antibiotic typically clear within seven to fourteen days. Herpesvirus-related conjunctivitis may take longer to resolve and can recur. Chlamydial infections generally require a full three to four weeks of antibiotic treatment to fully clear. If your cat’s symptoms are not improving within the first few days of treatment, contact your veterinarian for a reassessment — the cause may be different from what was initially suspected, or a secondary infection may have developed.

Can I use human eye drops on my cat?

No. Never use human eye drops, including over-the-counter redness relievers like Visine, on your cat without explicit veterinary approval. Many human eye drop formulations contain preservatives, vasoconstrictors, or active ingredients that are harmful to cats. Artificial tears specifically formulated for veterinary use may occasionally be recommended by your vet for comfort, but even these should not be used without guidance. Always consult your veterinarian before putting anything in your cat’s eyes.

Will cat conjunctivitis go away on its own?

Mild allergic or irritant-related conjunctivitis may resolve on its own once the triggering substance is removed from the environment. However, infectious conjunctivitis — caused by viruses, chlamydia, or bacteria — will generally not resolve without treatment, and waiting for it to clear on its own risks allowing the infection to worsen, spread to the other eye, damage the cornea, or become chronic. The safest approach is always to have a veterinarian examine the eye, identify the cause, and prescribe the appropriate treatment rather than waiting to see if the problem resolves spontaneously.

Is cat conjunctivitis painful?

Yes, conjunctivitis is uncomfortable and can be genuinely painful for cats, particularly when the cornea is involved or when the swelling is severe. Cats are stoic animals that tend to hide pain, so the absence of obvious crying or distress does not mean the cat is comfortable. Squinting, avoiding light, reduced appetite, and withdrawal from social interaction are all signs that a cat is experiencing ocular pain. Prompt treatment relieves discomfort and prevents the condition from progressing to more painful complications like corneal ulceration.

Can indoor cats get conjunctivitis?

Absolutely. Indoor cats can develop conjunctivitis from feline herpesvirus (which they may have carried since kittenhood), household allergens like dust or cleaning product fumes, or bacterial infections. While indoor cats are less exposed to certain contagious agents, they are not immune to eye problems. Stress — a known trigger for herpesvirus reactivation — can occur in indoor cats due to changes in routine, new household members, construction noise, or boredom. Keeping your indoor cat’s environment enriched, clean, and low-stress is one of the best ways to reduce the risk of conjunctivitis flare-ups. Browse our cat breeds directory to understand breed-specific health considerations that may influence your cat’s susceptibility to eye conditions.