Conjunctivitis in dogs
Conjunctivitis
Conjunctivitis is inflammation of the conjunctiva. Which is the tissue lining the
eye lids. The eye may be red, swollen or have a discharge.
In the dog, primary infectious conjunctivitis is probably not as common as
secondary conjunctivitis. Dogs should not experience repeated bouts of primary
infection, if they do, then an underlying cause needs to be investigated..
In dogs, infectious organisms are
(Staphylococcus, Streptococcus spp.)
usually
Gram-positive
bacteria
 Fusidic acid (Fucithalmic) has broad-spectrum, mostly Gram-positive
range of activity and is useful as a first-line treatment. It needs to be
applied only once daily.
 Chloramphenicol (Chloromycetin) is a good second choice, but
requires more frequent application (TID or QID)
 Gentamicin (Tiacil) is poorly effective against streptococci so is not a
suitable first-line treatment for canine conjunctivitis, although it is
effective in Gram-negative infections such as Pseudomonas
Secondary conjunctivitis
In dogs, secondary conjunctivitis is probably more common than primary
conjunctivitis. The underlying cause is often allergic or inflammatory, and may
include:
Keratoconjunctivitis sicca (KCS) or ‘dry eye’
Allergy
Distichiasis, Entropion
Corneal ulceration, Conjunctival foreign body
Keratoconjunctivitis sicca (KCS)
Keratoconjunctivitis sicca is the commonest cause of chronic conjunctivitis in
the dog. It is a condition which initially effcts the quality of the tear production,
and then eventually the volume of tears produced. Eventually leading to a dry
eye.
To test for the condition a small strip of litmus paper is inserted under the lower
eye lid and helfd in place for up to a minute. This allows the amount of tears
procuded in a minute to be measured. This is called a Schirmer tear test.
A red eye with a reduced Schirmer tear test, (<10mm in one minute) will
indicate that the dry eye is causing, or certainly contributing to, the
inflammation of the conjunctiva.
Treatment of KCS:
- Cyclosporine (Optimmune, Schering-Plough), applied twice daily. This
eye drop acts on the tear tissue, making it re produce the tears.
- ocular lubricant such as Viscotears, (CibaVision) applied four times
daily This is a cheaper option, and mimics the wetness of the tears, but
doesn’t contain any of the positive atibutes of the tears.
- Add topical antibiotic such as fusidic acid if a mucopurulent discharge is
present.
- Consider a parotid duct transplant if medical treatment is unsuccessful
(referral should also be considered at this stage)