Page 1334 - Problem-Based Feline Medicine

1326 PART 15 CAT WITH EYE PROBLEMS

Lesions may be seen at other sites on the skin, e.g. neck electrical insect destruction appliances, reducing
and face, ears, ventral abdomen. local mosquito or midge breeding grounds.
● Inhalant allergy: hyposensitization by a competent
Diagnosis dermatologist. Judicious use of oral corticosteroids
to control pruritis.
A tentative diagnosis is based on the appearance of the
● Contact allergy (to topical drugs): Withdraw
erythematous, crusting and/or pruritic lesions around
offending drug from use on the eye.
the eyelids, and the appearance of lesions on other parts
of the body, e.g. ears, for insect bite hypersensitivity.
EYELID TRAUMA/WOUNDS*
Confirmation of the diagnosis is based on the use of
appropriate tests or trials. Classical signs
● Food allergy diagnosis requires careful question-
● Linear defects or discontinuities.
ing about dietary history, followed by an appro-
● Puncture wounds with secondary cellulitis
priate food elimination trial using a single novel
and abscessation.
protein (1/3 cup) with potato or rice (2/3 cup), and
● Abrasions, excoriations, hemorrhage and
demonstration of an improvement in the appearance
crusting.
of the skin. Dietary trials should be performed for at
● Swelling with purple to red discoloration
least one month.
(bruising).
● Staphylococcal allergy is indicated by demonstra-
tion of an improvement after a trial course of
Pathogenesis
antibiotics, e.g. amoxicillin–clavulanic acid com-
bination at a dose rate of 12.5 mg/kg q 12 hourly for Trauma can be variable in its effect on eyelid structure.
at least 2 weeks. ● Sharp lacerating trauma tends to create linear
● Insect bite hypersensitivity is diagnosed by defects or discontinuities.
demonstration of an improvement after enclos- ● Puncturing trauma may not be readily obvious
ing the cat in an insect-proof enclosure for at unless infectious organisms introduced by the punc-
least 2–3 weeks. ture wound later cause cellulites.
● Atopy requires intradermal skin testing to help ● Abrading trauma causes surface excoriation,
identify the allergen. hemorrhage and crusting.
● Contact allergy should be suspected when with- ● Traumatic contusion (bruising trauma) will cause
drawal of the suspected offending drug from top- significant swelling and purple to red discoloration
ical use for 2–3 weeks results in resolution of signs. of the eyelid tissue.
Clinical signs
Differential diagnosis
Trauma to the eyelids should be suspected whenever
Immune-mediated skin disease can be ruled out on the
any of the following are observed:
basis of histopathology of skin biopsies by a competent
● Linear defects or discontinuities of the eyelid mar-
dermatohistopathologist.
gin or skin surface.
● Swelling.
Treatment ● Surface ulceration or excoriation.
● Surface hemorrhage or bruising.
Treatment is variable depending on the type of allergy:
● Serous ocular discharge and/or crusting.
● Food allergy: withdraw offending food protein from
● Associated trauma to the conjunctiva and/or globe.
the diet.
● Staphylococcal allergy: continue antibiotic treat-
Diagnosis
ment for at least 4 weeks.
● Insect bite hypersensitivity: use insect repellants on Diagnosis is based on the history of a known traumatic
or around the cat, or attempt to reduce insects by episode, and on the appearance of the eyelids suggest-
environmental control, e.g. use of mosquito coils, ing trauma.