Understanding Conjunctivitis in Pets: When It’s More Than Just an Infection

Red, swollen, or irritated eyes in pets can be concerning. While conjunctivitis is a common eye condition in dogs and cats, it can sometimes indicate a more serious underlying issue. Infections, allergies, autoimmune diseases, or even systemic illnesses may contribute to persistent eye inflammation. Identifying the cause early ensures the best outcome for your pet’s vision and comfort.

At Veterinary Vision Center in Shreveport, LA, we specialize in diagnosing and treating both routine and complex cases of conjunctivitis. Understanding when it’s more than just an infection is key to ensuring long-term eye health.

Learn more about our ophthalmic services: Veterinary Vision Center Services

What Is Conjunctivitis?

The Role of the Conjunctiva

The conjunctiva is a thin, protective membrane covering the white of the eye (sclera) and the inner eyelids. It plays an essential role in lubrication, immune defense, and protecting against environmental irritants.

When inflammation occurs, the conjunctiva becomes swollen, red, and irritated, leading to conjunctivitis, also known as pink eye in human medicine.

Types of Conjunctivitis

  • Infectious Conjunctivitis – Caused by bacterial or viral pathogens.
  • Non-Infectious Conjunctivitis – Linked to allergies, irritants, or systemic diseases.
  • Chronic or Recurrent Conjunctivitis – Often secondary to keratoconjunctivitis sicca (KCS or dry eye), eosinophilic conjunctivitis, or immune-mediated disease.

More on common eye conditions in pets: ACVO Eye Conditions

Causes and Risk Factors

Infectious Causes

  • Bacterial Conjunctivitis
    • Most common in dogs, caused by Staphylococcus, Streptococcus, or Pseudomonas.
    • Results in thick, mucopurulent discharge and eyelid swelling.
  • Viral Conjunctivitis
    • Frequently seen in cats, especially with feline herpesvirus (FHV-1).
    • Often presents with clear discharge, sneezing, and nasal congestion.
    • Other viral causes: Canine distemper virus, feline calicivirus.

Non-Infectious Causes

  • Allergic Conjunctivitis
    • Associated with pollen, dust, mold, and other environmental allergens.
    • Often seasonal, with itching and watery discharge.
  • Irritant-Induced Conjunctivitis
    • Triggered by smoke, dust, perfumes, household cleaners, and shampoo residue.
  • Autoimmune or Immune-Mediated Conjunctivitis
    • Seen in conditions such as pannus, pemphigus, and eosinophilic conjunctivitis.
    • May require long-term immunosuppressive therapy.

More on conjunctivitis classifications: Today’s Veterinary Practice – Conjunctivitis in Dogs and Cats

Signs That Indicate Conjunctivitis

Symptoms Pet Owners Should Watch For

  • Redness and swelling of the conjunctiva.
  • Watery, mucoid, or purulent discharge from one or both eyes.
  • Excessive blinking or squinting (blepharospasm).
  • Eyelid swelling (chemosis), causing discomfort.
  • Frequent pawing or rubbing at the eye, indicating irritation.

When Conjunctivitis Requires Further Investigation

  • Persistent symptoms beyond 10–14 days may indicate an underlying condition.
  • Chronic conjunctivitis could be associated with dry eye, glaucoma, or eyelid abnormalities.
  • Recurrent episodes may suggest autoimmune disease or chronic infections.

Schedule an ophthalmic evaluation for persistent conjunctivitis: Veterinary Vision Center

Diagnosing Conjunctivitis in Pets

Comprehensive Ophthalmic Examination

  • Fluorescein Staining – Detects corneal ulcers that may complicate conjunctivitis.
  • Schirmer Tear Test (STT) – Measures tear production to diagnose KCS (dry eye).
  • Tonometry – Evaluates intraocular pressure for glaucoma or uveitis.
  • Conjunctival Cytology – Identifies bacterial, fungal, or eosinophilic
  • PCR Testing – Confirms feline herpesvirus or canine distemper virus.

Advanced ophthalmic diagnostics available at: Veterinary Vision Center

Treatment Options for Conjunctivitis

Medical Management

  • Topical Antibiotics (for bacterial conjunctivitis)
    • First-line therapy includes neomycin-polymyxin-bacitracin or tobramycin.
    • Fluoroquinolones are reserved for more resistant infections.
  • Antiviral Therapy (for feline herpesvirus cases)
    • Cidofovir, idoxuridine, or L-lysine supplements help reduce viral activity.
  • Anti-Inflammatory and Immunosuppressive Therapy
    • Topical steroids (dexamethasone, prednisolone) for immune-mediated cases.
    • Cyclosporine or tacrolimus for chronic inflammatory conditions.

Supportive Care

  • Artificial tears or lubricating gels for dry eye and irritation.
  • Antihistamines or allergen control for allergic conjunctivitis.
  • Avoidance of irritants such as cigarette smoke and strong household chemicals.

Customized treatment plans available at: Veterinary Vision Center

When Conjunctivitis Indicates a More Serious Condition

Chronic, Recurrent, or Treatment-Resistant Cases

  • Persistent conjunctivitis could indicate immune-mediated, neoplastic, or structural abnormalities.
  • Further diagnostics, including conjunctival biopsy or tear film analysis, may be required.

Other Ocular Diseases That Mimic Conjunctivitis

  • Uveitis or intraocular inflammation associated with systemic diseases.
  • Glaucoma-related conjunctival irritation.
  • Orbital tumors causing persistent conjunctival swelling.

Advanced diagnostics for complex cases: Veterinary Vision Center

Preventative Measures for Pets Prone to Conjunctivitis

Routine Eye Exams and Early Detection

  • Annual or biannual exams recommended for at-risk breeds (Pugs, Bulldogs, Retrievers, Persian Cats).
  • Regular monitoring of tear production and corneal health prevents chronic irritation.

Hygiene and Environmental Modifications

  • Daily eye cleaning with veterinary-approved ophthalmic wipes.
  • Reducing exposure to allergens and irritants to prevent flare-ups.

Preventative ophthalmic care available at: Veterinary Vision Center

Referral to a Veterinary Ophthalmologist

When Specialty Care Is Needed

  • If conjunctivitis does not improve with initial treatment.
  • If signs of vision loss, corneal ulceration, or abnormal pupil responses are present.
  • If immune-mediated or systemic disease is suspected.

Schedule a referral appointment today: Contact Veterinary Vision Center

Additional Resources

More on Conjunctivitis and Eye Conditions: