Conjunctivitis in Cats: A Vet’s 2025 Guide to Pink Eye Causes, Diagnosis & Treatment 😺👁️
In this article
Conjunctivitis in Cats: A Vet’s 2025 Guide to Pink Eye Causes, Diagnosis & Treatment 😺👁️
By Dr Duncan Houston, BVSc
🔍 What Is Conjunctivitis?
Conjunctivitis—or "pink eye"—is inflammation of the conjunctiva: the mucous membrane lining the eyelids, third eyelid, and eye surface. This painful condition is common and can affect one or both eyes. :contentReference[oaicite:3]{index=3}
⚠️ What Causes It?
Infectious Causes:
- Viral: Feline herpesvirus‑1 (FHV‑1) is the most frequent, often recurrent agent. Calicivirus also contributes. :contentReference[oaicite:4]{index=4}
- Bacterial: Secondary to viral; or primary from pathogens like Chlamydophila felis, Mycoplasma, Staph, Strep, Bartonella, Pseudomonas. :contentReference[oaicite:5]{index=5}
Non‑infectious Causes:
- Allergic or irritant from pollen, smoke, perfumes. :contentReference[oaicite:6]{index=6}
- Trauma or foreign bodies like scratches, entropion, eyelash misalignment. :contentReference[oaicite:7]{index=7}
- Other pathology such as dry eye, eyelid tumors, uveitis, glaucoma. :contentReference[oaicite:8]{index=8}
🚩 Signs to Watch For
- Red, swollen conjunctiva with squinting and blinking. :contentReference[oaicite:9]{index=9}
- Discharge—watery, pus‑like, yellow/green or bloody. :contentReference[oaicite:10]{index=10}
- Visible third eyelid protrusion. :contentReference[oaicite:11]{index=11}
- Pawing at eye, tear staining, crusted eyelids, sensitivity to light. :contentReference[oaicite:12]{index=12}
- Associated respiratory signs—sneezing, nasal discharge, appetite loss in viral cases. :contentReference[oaicite:13]{index=13}
🔬 Diagnostic Steps
- Physical exam and ocular evaluation. :contentReference[oaicite:14]{index=14}
- Fluorescein stain to check corneal ulceration. :contentReference[oaicite:15]{index=15}
- Schirmer tear test for dry eye. :contentReference[oaicite:16]{index=16}
- Cytology or culture/PCR from eye swabs to identify pathogens like Chlamydia. :contentReference[oaicite:17]{index=17}
- Further systemic tests (e.g., FeLV/FIV) if indicated. :contentReference[oaicite:18]{index=18}
🛠️ Treatment Strategies
Topical Therapies:
- Antibiotic drops/ointments (2–4× daily for 2–3 weeks). :contentReference[oaicite:19]{index=19}
- Antiviral drops (e.g., idoxuridine) or oral antivirals for FHV‑1; supplements like L‑lysine. :contentReference[oaicite:20]{index=20}
- Anti‑inflammatory drops/steroids for allergies (under vet supervision). :contentReference[oaicite:21]{index=21}
Systemic Therapy:
- Oral antibiotics for systemic or deep bacterial infections (e.g., doxycycline for Chlamydia). :contentReference[oaicite:22]{index=22}
- Antihistamines or short-course steroids for allergic conjunctivitis. :contentReference[oaicite:23]{index=23}
Supportive Care:
- Warm compresses to soothe and remove crust.
- Keep eyes clean using saline wipes before medicating.
- Isolate infected cats and maintain hygiene to prevent spread. :contentReference[oaicite:24]{index=24}
🏡 Home Care & Prevention
- Follow full treatment courses—even if symptoms improve early.
- Reduce irritants: smoke‑free, dust‑free environment.
- Vaccinate against FHV‑1 and calicivirus for prevention. :contentReference[oaicite:25]{index=25}
- Use the **Ask A Vet** app for reminders, guidance, and virtual care.
- Provide comfort with soft bedding and calm zones using **Woopf** & **Purrz**.
📅 Prognosis & Follow-Up
- Most cases resolve in days to weeks. :contentReference[oaicite:26]{index=26}
- Chronic FHV-1 may relapse under stress; lifetime management may be necessary. :contentReference[oaicite:27]{index=27}
- Severe cases (ulcers) require referral to veterinary ophthalmologist.
- Recheck exams may include tear tests, cytology, and fluorescein stain.
📝 Quick Reference Table
| Aspect | Details |
|---|---|
| Cause | Viral (FHV‑1, calici), bacteria (Chlamydia, Mycoplasma…), allergens, trauma |
| Signs | Redness, discharge, blinking, third eyelid |
| Diagnostics | Exam, stain, tear test, cytology/culture |
| Treatment | Topical drops ± oral meds, clean eyes, comfort care |
| Prevention | Vaccines, hygiene, avoid irritants |
| Prognosis | Good if treated; chronic FHV may relapse |