Equus – August 2019

12 EQUUS 498 AUTUMN 2019

Cushing’s might have played a role in

other health issues she has had. For

instance, she seems to be prone to eye

infections; at least once a year we’ve

had to call the veterinarian and treat

her with antibiotic cream. She also gets

terrible rainrot each winter. Is it possible

these are related to the Cushing’s? Are

they likely to go away once the pergolide

begins to take effect?

Mary Benson

Reading, Pennsylvania

A:

Immunosuppression is an

important component of

Cushing’s disease, an endocrine

disorder technically known as pituitary

pars intermedia dysfunction (PPID).

Research has shown that the white

blood cells responsible for clearing

bacteria (neutrophils) do not function

as well in horses with PPID, increasing

Have a question about your horse’s health, care or training? Our experts offer solutions for

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EQ CONSULTANTS I

MANAGEMENT

A common eye problem

Q:

My mare, now almost 20, gets
conjunctivitis at least once
each summer. It seems to occur when
the weather is particularly hot and dry.
When it happens, her eye swells shut
within hours. My veterinarian has
assured me that my mare does not have
uveitis and he gave me an ointment
that clears up the problem in a few
days. Still, it’s unpleasant for her, and
it can interrupt my riding plans. Is
there a reason my mare might be more
susceptible to this than the other three
horses in her pasture (who don’t seem to
have this problem)? Are there steps I can
take to help prevent this?
Stacy Brennan
Carlsbad, New Mexico

A:

Conjunctivitis in horses is
relatively uncommon com-
pared to how frequently the condition
is observed in dogs and people.
Often referred to as “pinkeye,”
conjunctivitis is the inflammation
of the tissue around the eye. Horses
may have red conjunctiva, mild
discomfort and slight watery or
mucous discharge.
In horses, conjunctivitis is usually
caused by minor and self-limiting
bacterial or viral infections. But the
condition can be associated with
another primary underlying cause,
such as corneal disease or uveitis,
an inflammation of the pigmented
structures within the eyeball.
Therefore, anytime a horse owner
notices “pink eye” or ocular discharge
of any type, it is important to have an
experienced veterinarian give the horse
a complete eye examination, just as
you’ve done. Although conjunctivitis

itself rarely leads to long-term

problems, the potential underlying

causes can result in blindness.

As for preventing the condition,

you can try fitting your mare with a fly

mask, which will block wind, dust and

insects that may be irritating the eye

and triggering the reaction.

Brian Gilger, DVM, MS,

DACVO, DABT

North Carolina State University

Raleigh, North Carolina

DISEASE

Cushing’s and

immune function

Q:

My daughter’s pony was recently

diagnosed with Cushing’s

disease. She’s been put on pergolide

and we are taking steps to keep her safe

from laminitis. I’m wondering whether

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JUST IN CASE: Although conjunctivitis in horses is usually minor and self-

limiting, it can signal a more serious condition. So if you notice eye discharge,

redness or swelling, ask your veterinarian to conduct a complete ocular exam.