Client Fact Sheet #86
Conjunctivitis
Conjunctivitis is the inflammation of the tissues lining the eyelids. It is the most
common eye problem in cats and dogs.
Causes
There are many causes including:
• Allergies induced by pollen or grasses etc
• Viruses
• Bacteria
• Foreign bodies such as grass seeds
Symptoms
The symptoms vary depending on the cause. They include:
• Reddening of the eye. There may even be a swollen appearance to the eye.
• A discharge that can vary from being watery to thick and pussy. In severe
cases the eye(s) may become glued shut with this discharge.
• Conjunctivitis can be very painful, causing the cat or dog to paw at their face
and eyes and attempt to avoid bright light.
• In cats often the third eyelid will come across the eye.
• Eye swollen shut
Treatment
In some cases a sample of the discharge may be taken and sent to the laboratory
for analysis. This can determine if infection is the cause and what type of antibiotic
will be most effective. The eye will often have a special stain applied that shows up
any scratches or ulcers that are present. The presence of scratches or ulcers means
that certain medications cannot be used to treat the eye as these medications can
slow the healing of the eye or in some cases may even make the condition worse.
Topical eye drops or ointments are usually given to treat conjunctivitis. If the cause
is thought to be an infection then antibiotic drops/ointment will be given. If the
cause is more likely to be allergic then cortisone drops/ointment will be used.
Updated Sept 2012
Sometimes both types of medication will be given, or often mixed together. In
severe cases oral medication may be given as well as the topical medication.
Treatment needs to be continued for at least two days after the eye returns to its
normal appearance.
Conjunctivitis can lead to more serious eye problems, so if symptoms are not
improving despite treatment, it is important to have your pet rechecked.
Herpes conjunctivitis in cats
Unlike dogs, cats get a particular type of conjunctivitis that is caused by a herpes
virus. This conjunctivitis can be frustrating to treat as in some cats you can never
really get rid of it.
Herpes viruses grow in the tissues of the body such as the upper respiratory tissues
and conjunctivae. A Herpes virus infection typically causes respiratory signs of a
snotty nose and congestion and/or weepy eyes. When the conjunctiva is irritated, it
reddens and becomes itchy, dry, and uncomfortable. In severe cases the cornea can
be involved causing the eye to become cloudy and/or ulcerated. Because we cannot
treat the virus itself, treatment for viral conjunctivitis usually consists of antibiotic
treatment to cover any secondary bacterial infections while the body deals with the
virus on its own.
The tricky part of the herpes infection is that once the initial infection resolves the
virus itself does not go away; instead, it retreats into the cat’s immune system
where it stays “dormant”. In times of stress i.e. staying in a cattery, changes in the
home environment or being attacked by other cats, the immune system is taxed and
the virus is able to “escape”, leading to the return of symptoms. These individuals
will have recurring conjunctivitis in times of stress.
If you have any further questions please ask one of our experienced support staff
or phone us on 818 5697.
Updated Sept 2012