Ask the Vet – Causes of allergic reactions in horses

By Adem Lewis / in , , , , , , , , , , , , , , , , , , , , , , , , , , , , /

SARAH: “How do you tell
if a horse has an allergy to fly spray or
some other product? I’ve heard of horses having
reactions to citronella, but what are some other
common ingredients that horses may have a reaction to?” All right, so we
got two questions. How do you tell if your
horse is having a reaction? And what are some
common ingredients that might cause it? DR LYDIA GRAY: I better start
with the common ingredients because if I get
talking about the other, then I may forget it. So here’s a list that I found. Neoprene is in some
splint boots or girths. Some horses just don’t
do well with neoprene. Wool and the
lanolin in the wool, but there’s also lanolin in
products, like some shampoos and stuff have lanolin. Rubber or latex
like you might find wrapped on a bit or something. So those are some common
products that horses can have a local reaction to. And then, her first question
is, how do you tell? When you’re having a reaction to
something that you contacted– so contact dermatitis–
it’s in the area right where you touched it. So if you’re going to have
a sensitivity to bedding, then it’s where you
laid in bedding. So a horse might get up and have
a little shavings suck on them and then have bumps
too right there. If it’s a neoprene or
something, then right where you put the
neoprene or the wool might be in the saddle area. If there’s something
on the bridle. So if she’s talking
about fly spray, if you sprayed it in an
area– a certain area– it would be exactly
where that spray landed. And then the signs would be
the hives, the bumps, itching, maybe some dryness or hair loss. But what you do is you
don’t put something on a horse on its entire
body the first time. You do a patch test
or a spot test. And you just pick a little
area, you apply the product, and then you wait
24 to 48 hours. If your horse is going
to have a local reaction, it will happen in
that time frame. If not, chances
are, he’s OK with it and you can use it
everywhere you need to. So did I answer that? SARAH: I think that answers
both of the questions. Do you now– and this is a
separate but kind of related question– if horses are, like–
and this might not even be true for people. But I’ve heard that if
the first time you’re exposed to something, you might
not have an allergic reaction. But then subsequent
exposure could cause it. Do we see that same
sort of thing in horses? DR LYDIA GRAY: Yes. But allergies are different. So you can have a
contact dermatitis that is not allergic. And you can have hives that
are not because of allergies that are just because of– SARAH: –irritation. DR LYDIA GRAY: Yeah. So a local skin response,
the local ones probably aren’t systemic immune-related. And so that
phenomena that you’re describing of the first
time, you get a freebie. And the second time, well,
that’s not going to happen. SARAH: Because that’s
more related to allergies. It’s not related specifically. DR LYDIA GRAY: Now,
if the horse has a true allergy to
a substance, then yes, it takes exposure the first
time and then the next time, they get worse. So that can happen too. And that’s why allergies
and hives due to allergies are so challenging to figure
out because you don’t know what the things were that
could have caused this because it’s systemic. Like contact ones,
the reaction is right there where you put it. SARAH: It’s localized. DR LYDIA GRAY: Right. And systemic ones, the true
allergies are like whole body. But it could have been something
that they touched or inhaled or ate. And so then, you’re back to
that process of elimination. SARAH: Yeah. DR LYDIA GRAY: Ugh. SARAH: But what you can
do to help yourself out in a situation like that is
something my good friend Dr. Gray always does,
which is journal what you’re doing with your horse. Because if you write
in your journal that you started your
horse on a new feed, or you introduced
a new product– whether it’s a topical product
or a piece of equipment that has wool in it that
you’ve never used before– and then a couple
days later, you notice that
something’s happening, those might be trends you could
share with your veterinarian to help you in that overwhelming
process of elimination of all of the things that could
be causing what’s going on.

5 thoughts on “Ask the Vet – Causes of allergic reactions in horses

  1. Thanks, this was helpful! I will be getting my first horse is 1-3 years. Big range i know, but now I know how to test for allergies.

  2. My pony is extremely allergic to the girth on my bareback pad, I'm not sure what material it is but it's rubbery and grippy, he gets swelling all around his girth area and the swelling is 3cm thick. The swelling is so bad that it looks like he has a girth on, when it's just swelling!

  3. My horse can’t gain mussel for the life if him on his top line and butt do you have any tips? #FlabbyHorse #AskTheVet

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