called red eye or pink eye, is an inflammation of the conjunctival membrane
that covers the back of the eyelids and the surface of the
eyeball, up to the cornea. It is one of the most
common eye problems in dogs.
The classic signs of conjunctivitis are a red eye with a discharge.
Conjunctivitis is not usually painful.If the eye is red and the dog is
squinting and shutting the eye, consider the possibility of keratitis, uveitis, or glaucoma. Any delay in treating
these conditions can lead to blindness.
When the discharge involves both eyes, suspect an allergy or a systemic disease such as canine distemper. When it involves
only one eye, consider a local predisposing cause such as a foreign body in the
eye or hair rubbing on the eye.
The eye discharge in conjunctivitis
may be clear (serous), mucuslike (mucoid), or puslike (purulent).A stringy,
mucoid discharge suggests the dog may have inadequate tear volume, a problem
associated with keratoconjunctivitis sicca.In fact, this is the most common
cause of conjunctivitis in dogs.
Serous conjunctivitis is a mild condition in which the membranes look pink
and somewhat swollen. The discharge is clear and watery. Serous conjunctivitis
is caused by physical irritants such as wind, cold, dust, and various allergens
such as those that cause allergic blepharitis. Allergic conjunctivitis is often
accompanied by itching, and the dog will rub
his face. Some viral agents will cause a clear discharge as well.
Follicular (mucoid) conjunctivitis is a condition in which the small mucous
glands (follicles) on the underside of the nictitating membrane react to
an eye irritant or infection by
forming a rough, cobblestone surface that irritates the eye and produces a
mucoid discharge. After the inciting factor has been treated, the follicles may
persist and the rough surface acts as a chronic irritant.
Purulent conjunctivitis is serous conjunctivitis that becomes infected. The
usual culprits are the bacteria Streptococcus and Staphylococcus. The
conjunctiva is red and swollen. The eye discharge contains mucus and pus. Thick secretions may crust
Treatment: Any underlying cause of conjunctivitis should be corrected. Dogs
with recurrent or persistent conjunctivitis should be tested for
Serous conjunctivitis can be treated at home. Flush the eye three or four
times a day with an over-the-counter sterile saline eyewash or artificial
tears. Notify your veterinarian if the eye appears to be getting worse.
Mild cases of follicular conjunctivitis respond to antibiotic and
corticosteroid eye ointments prescribed by your veterinarian. In resistant
cases, the follicles may need to be destroyed by chemical cauterization.
Purulent conjunctivitis requires veterinary examination and treatment. It is
important to remove mucus and pus from the eyes, as well as pus and crusts that
adhere to the eyelids. Moisten a cotton ball with sterile eyewash and gently
cleanse the eye. Warm, moist packs may help loosen crusts. Repeat as necessary
and apply topical antibiotics as prescribed by
your veterinarian (see How to Apply Eye Medicines, page 174). Continue topical
antibiotics for several days beyond apparent cure.
Note that corticosteroids and eye medications containing corticosteroids
should not be used in dogs with purulent conjunctivitis because they impair the
local inflammatory response that fights infection. Bacterial culture and
sensitivity tests are indicated if the conjunctivitis does not improve.