Conjunctivitis in Cats: Causes, Symptoms, Diagnosis, and Effective Treatments

Keeping your cat’s eyes healthy starts with spotting changes and seeking timely care.

By Medha deb

Created on Sep 10, 2025

Keeping your cat’s eyes healthy starts with spotting changes and seeking timely care.

Conjunctivitis, commonly referred to as âpink eye,â is one of the most frequent eye conditions affecting cats. Whether caused by infection, allergies, or injury, the inflammation of the conjunctiva (the delicate tissue lining the eyelids and covering the white of the eye) can cause discomfort, discharge, and, if left untreated, more serious complications. This comprehensive article explores the causes, symptoms, diagnosis, and treatments for feline conjunctivitis, helping cat owners understand what to expect and how best to support their petâs eye health.

What Is Conjunctivitis?

Conjunctivitis is the medical term for inflammation of the conjunctivaâthe thin, moist membrane that lines the inner eyelids and covers the sclera (the eyeâs white portion). This membrane provides immune defense, lubricates the eye, and protects delicate ocular tissues. When it becomes irritated or infected, its blood vessels expand, leading to noticeable symptoms such as redness, swelling, and discharge. While conjunctivitis itself is not usually life-threatening, it is uncomfortable and may be a sign of a more serious, systemic illness.

Causes of Conjunctivitis in Cats

The causes of conjunctivitis in cats are diverse and often grouped into two main categories: infectious and non-infectious.

1. Infectious Causes

Viral Infections:
- Feline Herpesvirus (FHV-1, aka Feline Viral Rhinotracheitis): The most common infectious cause, often responsible for chronic or recurring cases.
- Feline Calicivirus (FCV): Another frequent viral culprit, especially in multi-cat environments.
Bacterial Infections:
- Chlamydophila felis: A primary bacterial cause, particularly in kittens and young cats.
- Mycoplasma species: Can cause both primary and secondary conjunctivitis.
- Bartonella henselae: Occasionally implicated, especially in immunosuppressed cats.
- Secondary Bacterial Infections: Can complicate viral conjunctivitis, making symptoms more severe.
Fungal Infections: Rare, but may occur in certain geographic areas or immunocompromised cats.

2. Non-Infectious Causes

Allergies: Common allergens include pollen, dust, mold, household chemicals, smoke, and certain plants.
Foreign Bodies: Dust, sand, plant material, or debris that gets trapped beneath the eyelid.
Trauma: Scratches, abrasions, or other injuries to the eye or eyelid can trigger inflammation.
Anatomic Abnormalities: Congenital defects such as entropion (inward-rolling eyelids) or eyelid agenesis (failure of the eyelid to form) commonly cause irritation.
Dry Eye (Keratoconjunctivitis Sicca, KCS): Reduced tear production leads to dryness and inflammation.
Immune-Mediated Disorders: The catâs immune system targets the conjunctival tissues, resulting in persistent inflammation.
Tumors: Both benign (non-cancerous) and malignant (cancerous) growths in or around the eye.
Systemic Diseases: Chronic illness or viruses that suppress the immune system, such as Feline Immunodeficiency Virus (FIV) or Feline Leukemia Virus (FeLV), can predispose cats to conjunctivitis or worsen its severity.

Symptoms of Conjunctivitis in Cats

Many of the following signs can be seen in one or both eyes, and may range from mild to severe:

Redness and increased visibility of blood vessels within the eyeâs white area.
Swelling of the conjunctiva, eyelids, or the third eyelid (nictitating membrane).
Eye Discharge:

Clear and watery (more typical of allergies or viral infection).
Thick, yellow, green, or dark-colored (more likely bacterial infection).

Frequent blinking or squinting.
Pawing at the face or rubbing the eyes (may lead to self-trauma).
Sensitivity to light (photophobia).
Crusting around the eyelids.
Visible third eyelid covering part of the eye.
Behavioral changes: hiding, irritability, or decreased appetite due to discomfort.

Symptom	Possible Cause
Red, swollen eyes	Inflammationâany cause
Clear discharge	Allergy, viral infection
Thick/discolored discharge	Bacterial infection
Squinting / blinking	Pain, irritation, light sensitivity

Diagnosis: How Vets Determine the Cause

A veterinarian will start with a thorough physical and eye exam. Because conjunctivitis shares symptoms with other eye diseases, proper diagnosis is essential. Diagnostic steps may include:

Full history and physical examâincluding questions about the onset, duration, and progression of symptoms, as well as exposure to other animals or environmental changes.
Eye exam using an ophthalmoscope to assess the conjunctiva, cornea, eyelids, and underlying structures.
Fluorescein staining to detect corneal ulcers or scratches.
Schirmer tear test to diagnose dry eye (KCS).
Cytology and culture of eye dischargeâespecially for chronic or recurrent casesâto identify infectious agents and determine antibiotic sensitivity.
Blood tests if a systemic viral infection, immune-mediated disease, or chronic illness is suspected.
Advanced imaging (e.g., ultrasound, CT scan) if tumors or anatomic defects are suspected.

Treatment Options for Cat Conjunctivitis

Treatment is guided by the underlying cause, severity of symptoms, and whether one or both eyes are affected. Some cases are self-limiting, but many require veterinary intervention for symptom relief and to prevent complications.

1. Treating Viral Conjunctivitis

Supportive care: Keeping the eye clean with saline solution and using artificial tears to maintain moisture.
Antiviral medications: Prescribed as eyedrops, ointments, or in severe cases, oral medication, especially for FHV-1.
Minimize stress: Since herpesvirus can reactï¿½ï¿½ï¿½ during times of stress, reduction of household stresses may help reduce flare-ups.
Isolate affected cats: To prevent spread if due to a contagious viral infection.

2. Treating Bacterial Conjunctivitis

Topical antibiotics: Eye drops or ointments targeting the specific bacteria, applied two to four times daily as prescribed.
Systemic antibiotics: For severe, resistant, or deep-seated infections, oral antibiotics may be required.
Follow-up examinations: Ensures resolution and prevents chronic infection or spread to other eye structures.

3. Treating Allergic Conjunctivitis

Allergen avoidance: Remove or reduce exposure to known triggers (e.g., smoke, cleaning products, pollens).
Topical antihistamines or corticosteroids: Help reduce inflammation. Only to be used under veterinary supervision; steroids can worsen viral infections.
Dietary modification: In cases of suspected food allergies, hypoallergenic diets may be suggested.

4. Treating Non-Infectious Conjunctivitis

Foreign body removal: The veterinarian may flush or remove any debris manually under anesthesia if needed.
Anatomic correction: Surgical repair for eyelid defects such as entropion or agenesis.
Pain relief: Analgesic medications or artificial tears to improve comfort and reduce inflammation.
Treatment of underlying systemic disease: Management of conditions like FeLV, FIV, or autoimmune disorders as part of an overall plan.

General Home Care for Cats with Conjunctivitis

While veterinary guidance is essential, you can support your catâs recovery and minimize the risk of recurrence with the following:

Gently clean eye discharge with a sterile, damp cotton ball or gauze.
Administer all medications as prescribed for the full duration, even if symptoms quickly improve.
Keep your cat indoors during treatment to prevent further exposure or environmental irritants.
Minimize stress and provide a quiet, comfortable environment.
Wash hands thoroughly after treating your catâs eyes, especially if infection is present.
Avoid using human eye medications unless specifically instructed by your veterinarian.

Prognosis for Cats with Conjunctivitis

The outlook for cats with conjunctivitis is generally excellent when the underlying cause is diagnosed early and appropriately treated. Most cases resolve within 1â2 weeks of therapy. Chronic or recurrent casesâespecially those linked to herpesvirus, anatomical defects, or immune conditionsâmay require ongoing management, but most cats live normal lives with good quality of care.

Preventing Conjunctivitis in Cats

Maintain regular veterinary visits for general wellness and vaccination against respiratory viruses.
Reduce exposure to sick animals, especially in multi-cat households or shelters.
Keep the living environment clean and free from dust, smoke, or chemical irritants.
Promptly treat respiratory infections or systemic illnesses to reduce the risk of ocular involvement.
Genetic issues like entropion may be prevented through careful breeding.

Frequently Asked Questions (FAQs)

What is the difference between conjunctivitis and a regular eye infection?

Conjunctivitis specifically involves inflammation of the conjunctiva, while an eye infection may affect any part of the eye, including the cornea, lens, or internal structures.

Is conjunctivitis in cats contagious?

If conjunctivitis is caused by infectious agents (viruses or bacteria), it can be highly contagious to other catsâespecially in shelters, multi-cat homes, or catteries. However, it is not considered contagious to humans or dogs in most cases.

How quickly should I see a vet if my cat has red, swollen eyes?

Prompt veterinary attentionâideally within 24â48 hoursâis recommended. Rapid treatment reduces the risk of complications and improves outcomes.

Can I use over-the-counter human eye drops for my cat?

No. Human eye medications, especially those containing steroids, can be dangerous for cats and may worsen infections. Use only products prescribed by your veterinarian.

What are signs that conjunctivitis is getting worse?

Increasing redness, swelling, inability to open the eye, green or yellow discharge, change in vision, or evidence of pain (crying, hiding, not eating) warrant immediate veterinary attention.

Can conjunctivitis lead to blindness?

If left untreated or if the underlying cause is severe, conjunctivitis can harm other structures in the eye, potentially resulting in impaired vision or, rarely, blindness. Early treatment makes this unlikely.

Key Takeaways for Cat Owners

Conjunctivitis is common and can be caused by infections, trauma, allergies, anatomic defects, and underlying diseases.
Symptoms include redness, swelling, discharge, squinting, and behavioral changes.
Prompt veterinary evaluation is crucial for correct diagnosis and treatment.
Treatment is tailored to the cause and may include topical or systemic medications, surgical correction, and supportive care.
With proper care, most cats recover fully and maintain good eye health.

References

Author

medha deb

Medha Deb is an editor with a master's degree in Applied Linguistics from the University of Hyderabad. She believes that her qualification has helped her develop a deep understanding of language and its application in various contexts.

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