What is conjunctivitis?
Conjunctivitis is inflammation of the conjunctiva β the mucous membrane lining the inner eyelids and the front of the eyeball. It is the most common eye problem in dogs and can affect one or both eyes.
Main symptoms
- Eye discharge: watery (clear), mucoid (white/yellowish) or mucopurulent (thick green/yellow).
- Redness of the conjunctiva ("red eye").
- Excessive blinking or difficulty opening the eye.
- Pawing at the eye or rubbing the face along the ground.
- Swelling of the eyelids.
Common causes
- Allergic: pollens, dust, smoke. Bilateral, watery, itchy. Seasonal or year-round.
- Bacterial: secondary to another problem or primary (Staphylococcus, Streptococcus). Mucopurulent discharge. Responds to antibiotic eye drops.
- Viral: associated with distemper, canine herpesvirus (in puppies), adenovirus.
- Keratoconjunctivitis sicca (KCS / dry eye): insufficient tear production β dry, chronically inflamed eye. Thick mucoid discharge. Common in Bulldogs, Yorkshire Terriers, West Highlands. Treatment: cyclosporine or tacrolimus eye drops.
- Foreign body: hair, seed, dust. Unilateral, sudden onset, heavy blinking and epiphora.
- Entropion / distichiasis: inward-rolling eyelid or misplaced eyelash rubbing the cornea. Common in brachycephalic breeds and Chow Chows. Requires surgical correction.
Veterinary diagnosis
- Schirmer tear test (tear production).
- Fluorescein staining (rule out corneal ulcer β essential before using any steroid drops).
- Culture and sensitivity if the response to empirical antibiotics is unsatisfactory.
Treatment
- Allergic: antihistamine or mild corticosteroid drops (never if an ulcer is present).
- Bacterial: topical antibiotic (tobramycin, neomycin, chloramphenicol) 3β4 times daily.
- Dry eye (KCS): 0.2% cyclosporine ophthalmic or tacrolimus + frequent lubricant drops.
- Foreign body: removal + preventive antibiotic drops.
When is it an emergency?
- Eye held completely closed (severe blepharospasm).
- White or discoloured spot on the cornea (possible perforated ulcer or uveitis).
- Markedly prolapsed third eyelid.
- Intense pain, photophobia.
- Recent eye trauma.