Page 1229 - Problem-Based Feline Medicine

59 – THE CAT WITH OCULAR DISCHARGE OR CHANGED CONJUNCTIVAL APPEARANCE 1221

Systemic drugs may be used in conjunction with topi- The cornea may be ulcerated, and have intense neo-
cal medications, because the conjunctiva has a very rich vascularization in chronic cases.
blood supply.
The third eyelid may also show proliferative lesions.
Mucopurulent discharge is usually present.
EOSINOPHILIC KERATOCONJUNCTIVITIS*
Frequently, there is a history of poor response to antibi-
Classical signs otic treatment.
● Proliferative white to pink inflammatory
tissue on cornea with adjacent conjunctiva Diagnosis
sometimes involved. Initial diagnosis is based on a history of poor
● The cornea may be intensely vascularized. response to antibiotic treatment, together with signs of
● Mucopurulent discharge is usually present. a proliferative keratitis and/or conjunctivitis, and
● Eosinophils in cytology of affected cornea a mucopurulent discharge.
and/or conjunctiva are diagnostic.
Cytology or histopathology that demonstrates eosino-
See the main reference on page 1245 for details (The Cat phils is regarded as diagnostic.
With Abnormalities Confined to the Cornea). Affected animals may have signs of skin disease or
a history of digestive problems.
Pathogenesis
In tropical climates, check the ears for signs of insect
The disease is thought to be immune-mediated or an bites (mosquitoes and midges).
allergic response.
Histologically, there is a granulomatous response, Differential diagnosis
with a mixed population of leukocytes including lym-
Chronic chlamydial conjunctivitis may look similar
phocytes, plasma cells, eosinophils and occasional mast
when there is inflamed conjunctiva and follicle forma-
cells and histiocytes. The presence of eosinophils is
tion. Differentiate with histology or cytology, and look
regarded as diagnostic.
for the presence of eosinophils typically seen in
Peripheral eosinophilia is present in about 15% of eosinophilic keratoconjunctivitis.
cases.
Insect bites and food allergies have been documented as Treatment
causes of this condition. It has also been suggested that this
The condition will rapidly respond to systemic cortico-
response may be an ocular form of the feline eosinophilic
steroids dosed at 1 mg/kg daily. Once the inflammatory
granuloma complex, particularly the linear granuloma
response is controlled, then alternate day therapy at 0.5
response. (See The Cat With a Cloudy Eye, page 1262).
mg/kg can be used until all signs have disappeared.
Clinical signs Topical corticosteroids alone, using 1% prednisolone
acetate drops or dexamethasone 0.1% drops q 8 h
Signs begin unilaterally, but may become bilateral.
will control some cases, or be useful as a maintenance
Eosinophilic keratoconjunctivitis is a proliferative (not treatment for long-term control.
ulcerative) lesion producing plaque-like white to pink
If the tips of the ears show alopecia, pruritis and crust-
tissue, that may be covered by a thick white discharge.
ing, the condition may be caused by biting insects.
The cornea is involved primarily, and the adjacent Such cases have been documented in Queensland,
conjunctiva is sometimes involved secondary to corneal Australia. In such cases, the cats must be housed in
involvement. conditions that are insect free for long-term resolution.