Conjunctivitis in Cats: Causes, Treatment & Pink Eye

Quick Answer
  • Conjunctivitis is inflammation of the conjunctiva, the tissue lining the eyelids and covering the white of the eye. It is one of the most common eye problems in cats.
  • Common causes include feline herpesvirus-1, Chlamydia felis, Mycoplasma, upper respiratory infections, irritants, allergies, eyelid problems, and corneal injury.
  • Many cats need an eye exam with fluorescein stain before treatment, because a red eye can also be a corneal ulcer, glaucoma, uveitis, or a foreign body.
  • Treatment may include topical antibiotics, oral antibiotics, antiviral medication such as famciclovir in selected cases, pain control, and follow-up. Mild cases may improve quickly, but recurrent herpes flare-ups can return.
  • Typical 2025-2026 US cost range is about $120-$650 for straightforward cases, with higher costs if testing, repeat visits, or ophthalmology referral are needed.
Estimated cost: $120–$650

What Is Conjunctivitis in Cats?

Conjunctivitis means inflammation of the conjunctiva, the thin pink tissue that lines the inside of the eyelids and covers the white part of the eye. When that tissue becomes irritated, it can look red, swollen, and moist, and your cat may develop tearing, squinting, or eye discharge. It can affect one eye or both eyes.

In cats, conjunctivitis is often linked to infections that also cause upper respiratory signs, especially feline herpesvirus-1. It can also happen with bacterial infections, irritants, allergies, eyelid abnormalities, or other eye disease. That matters because “pink eye” is a description, not a final diagnosis.

Some cases are mild and improve with supportive care and medication from your vet. Others need faster attention because a painful red eye can also mean a corneal ulcer, trauma, glaucoma, or uveitis, which can threaten vision if treatment is delayed.

Symptoms of Conjunctivitis in Cats

  • Red or swollen pink tissue around the eye or under the eyelids
  • Clear, watery, mucoid, yellow, or green eye discharge
  • Squinting, blinking more than usual, or holding the eye closed
  • Pawing at the eye or rubbing the face on furniture
  • Third eyelid showing more than usual
  • Crusting on the eyelids or fur below the eye
  • Sneezing or nasal discharge along with eye signs
  • Light sensitivity or acting painful when the eye is touched

Mild conjunctivitis may look like a watery or slightly goopy eye with mild redness. More concerning signs include marked swelling, thick discharge, obvious pain, cloudiness on the eye surface, unequal pupils, or your cat keeping the eye shut. See your vet immediately if the eye looks cloudy, your cat seems very painful, vision seems affected, there was trauma, or a kitten’s eyes are swollen or sealed shut.

What Causes Conjunctivitis in Cats?

The most common infectious trigger is feline herpesvirus-1 (FHV-1), especially in kittens, shelter cats, and cats with a history of upper respiratory infections. Herpes can stay dormant in the body and flare again during stress or illness. Other infectious causes include Chlamydia felis and Mycoplasma, and some cats develop conjunctivitis as part of a broader respiratory infection.

Noninfectious causes matter too. Dust, smoke, sprays, grooming products, foreign material under the eyelid, trauma, allergies, eyelid problems such as entropion, and other eye diseases can all cause a red, irritated eye. In flat-faced cats, facial shape and tear drainage issues may also contribute to chronic irritation.

Because the same outward signs can come from very different problems, your vet may recommend testing before choosing treatment. That is especially important if the eye is painful, the cornea looks cloudy, only one eye is affected after outdoor exposure, or the problem keeps coming back.

How Is Conjunctivitis Diagnosed?

Your vet will start with a full eye exam and history. That usually includes checking the eyelids, third eyelid, cornea, pupil responses, and the type of discharge. A fluorescein stain is commonly used to look for corneal ulcers or scratches, because some medications are not appropriate if an ulcer is present.

Depending on the exam, your vet may also measure tear production or eye pressure, look for a foreign body, or collect a swab or scraping for cytology or PCR testing. Testing is more likely if the problem is severe, recurrent, affecting multiple cats in the home, or not improving as expected.

Many uncomplicated cases are treated based on exam findings first. If your cat is not improving within the expected timeline, or if the eye becomes more painful, your vet may adjust the plan or recommend referral to a veterinary ophthalmologist.

Treatment Options for Conjunctivitis in Cats

Spectrum of Care means you have options. Here are treatment tiers at different price points.

Conservative Care

$120–$220
Best for: Mild, first-time conjunctivitis in an otherwise bright cat when the cornea is intact and there are no signs of severe pain or vision change.
  • Office exam
  • Fluorescein stain to rule out a corneal ulcer
  • Basic topical antibiotic ointment or drops when indicated
  • Gentle eyelid cleaning with sterile saline or warm damp cotton
  • Home monitoring instructions and recheck only if not improving
Expected outcome: Often good for uncomplicated cases. Many cats improve within a few days, though treatment commonly continues for 1-3 weeks.
Consider: This tier keeps testing limited, so the exact cause may remain uncertain. It may be less helpful for recurrent herpes flare-ups, multi-cat households, or cases that are not responding quickly.
Most Common

Standard Care

$220–$450
Best for: Most cats with moderate conjunctivitis, recurrent episodes, respiratory signs, or discharge suggesting infectious disease.
  • Comprehensive eye exam with fluorescein stain
  • Targeted medication plan based on likely cause
  • Topical antibiotic or anti-inflammatory therapy when appropriate
  • Oral doxycycline or azithromycin in selected bacterial cases such as suspected Chlamydia felis
  • Oral famciclovir in selected herpesvirus cases
  • Pain control or supportive care if needed
  • Scheduled recheck visit
Expected outcome: Very good in many cases when treatment matches the cause. Herpes-associated disease can improve well but may recur during stress or illness.
Consider: This tier costs more and may involve multiple medications. Some treatments need frequent dosing, and oral antibiotics or antivirals may cause stomach upset in some cats.

Advanced Care

$450–$1,200
Best for: Cats with severe pain, corneal disease, chronic or recurrent conjunctivitis, poor response to first-line treatment, or suspected structural eye disease.
  • Veterinary ophthalmology consultation
  • PCR or cytology testing for herpesvirus, Chlamydia felis, or Mycoplasma when useful
  • Eye pressure testing and advanced diagnostics
  • Treatment of corneal ulcers, keratitis, sequestrum, entropion, or chronic tear film problems if present
  • Compounded antiviral drops such as cidofovir or other specialist-directed therapy when indicated
  • Serial rechecks for chronic, painful, or vision-threatening disease
Expected outcome: Often good with a tailored plan, but long-term management may be needed in chronic herpesvirus or complex eye disease.
Consider: Higher cost range, more visits, and more intensive home care. Advanced care is not necessary for every cat, but it can be the right fit when the diagnosis is unclear or the eye is at risk.

Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.

Questions to Ask Your Vet About Cat Conjunctivitis

Bring these questions to your vet appointment to get the most out of your visit.

  1. What is on your list of likely causes for my cat’s red eye? Conjunctivitis can be caused by infection, irritation, eyelid problems, or deeper eye disease, and the treatment plan depends on the cause.
  2. Does my cat need a fluorescein stain or other eye tests today? These tests help rule out ulcers, pressure problems, and other conditions that can look like pink eye.
  3. Do you suspect feline herpesvirus, Chlamydia felis, or another infection? Knowing the likely trigger helps you understand whether topical medication, oral antibiotics, antivirals, or monitoring makes the most sense.
  4. How often do I need to give this medication, and what if I miss a dose? Eye medications often need frequent dosing, so clear instructions improve follow-through and outcomes.
  5. Are any of these medications unsafe if there is a corneal ulcer? Some anti-inflammatory eye medications are not appropriate in ulcer cases, so this is an important safety question.
  6. When should I expect improvement, and when should I call sooner? A timeline helps you know whether healing is on track or whether the plan needs to change.
  7. Should I separate this cat from my other cats for now? Some infectious causes spread more easily in multi-cat homes, especially when respiratory signs are present.
  8. If this keeps coming back, what would the next diagnostic step be? Recurrent cases may need testing, a different medication plan, or referral rather than repeating the same treatment.

Can Conjunctivitis Be Prevented?

You cannot prevent every case, but you can lower risk. Keeping your cat current on core vaccines such as FVRCP helps reduce the severity of common respiratory infections linked to conjunctivitis. Good ventilation, low-dust litter, and avoiding smoke, sprays, and harsh cleaners around the face can also help.

If your cat has a history of herpes flare-ups, stress reduction matters. Stable routines, enough litter boxes and resting spaces, gradual introductions, and prompt treatment of other illnesses may reduce recurrences. In multi-cat homes, separate cats with active eye and respiratory signs until your vet advises otherwise.

Do not use leftover eye medication or human eye drops unless your vet specifically tells you to. Some products can worsen the problem or delay diagnosis. If your cat develops a red, painful, or goopy eye, early veterinary guidance is the safest next step.

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