| Allergies
Allergies ...
helping dogs and cats get the itch out
by: Shawn Messonier, DVM
Photo: Lisa
Ryan
 Kim
noticed that her cat Malcolm, a gray domestic
shorthair, had started scratching a lot.
She took a closer look and found what
looked like a red rash on his skin. “It
was quite inflamed in places and must
have been making him really uncomfortable.”
Kim took Malcolm to the vet and was told
he had allergic dermatitis.
Malcolm is far from alone in his itchy
complaint. In fact, allergic dermatitis
is among the most commonly diagnosed problems
in companion animals. It’s broken
down into two possible causes. One is
food allergic dermatitis, which is treated
by determining the food allergen (wheat,
beef, soy and corn are common offenders)
and eliminating it from the diet. The
most common is atopic dermatitis, which
is triggered by foreign proteins (allergens
such as pollens, dust mites, etc.) that
contact the animal’s skin and cause
itching. This article will focus on the
latter.
How is atopic
dermatitis diagnosed?
Diagnosing allergies is usually done quite
easily based upon history, examination,
and ruling out other diseases such as
ringworm and mange. Most allergic dogs
are itchy without skin lesions, unless
a secondary infection is present, whereas
allergic cats usually have scabs (military
lesions) or red patches (eosinophilic
lesions) on their bodies.
Alternative practitioners may use a homeopathic
procedure (NAET) to diagnose allergies
and find the most appropriate alternative
therapy. Sometimes, the animal will be
referred to a veterinary dermatologist.
Specialized intradermal skin testing will
allow the doctor to make the diagnosis.
Blood testing (ELISA) may be helpful but
is not as accurate as skin testing, and
is of no use in diagnosing food allergies.
Conventional
treatment options
Treating the allergic animal is usually
straightforward but can at times be challenging,
especially with chronically itchy dogs
and cats. There are two general schools
of treatment: the conventional approach
practiced by most veterinarians, and the
integrative approach practiced by holistic
vets such as myself.
The conventional approach, as expected,
relies heavily on medications, mainly
corticosteroids (prednisone and others)
or antihistamines. Several different antihistamines
may help dogs and cats with allergies,
including Benadryl, Chlortrimeton, Atarax,
and Tavist (and their generic equivalents).
While antihistamines are usually safer
than corticosteroids, there are potential
problems. First, some animals do not respond
to antihistamines. Since the vet has no
way of knowing if your companion will
have reduced itching with the administration
of an antihistamine, he will usually prescribe
one that has shown the greatest response
in his patients. If there is no response
after five to seven days, another antihistamine
may be tried. This trial and error approach
is usually continued until either a helpful
antihistamine is found, or no response
is seen to any medication.
A second problem with antihistamines is
that unlike a once-a-day dose of oral
corticosteroid, most antihistamines need
to be given at least two to three times
per day, which is inconvenient for some
people. Finally, some animals get very
drowsy with antihistamines.
Corticosteroids are often prescribed to
allergic dogs and cats, as they are extremely
effective at controlling itching and inflammation.
Corticosteroids are given either by injection
or orally. Injections contain either long-acting
(depot) medications (which lasts in the
animal’s body for two to three months,
even though the anti-itching effect can
wear off in some animals in as little
as one or two weeks), or short-acting
medications (usually lasting 12 to 24
hours in the body). If needed, I prefer
the short-acting injections as they are
unlikely to cause harm to the animal.
Whenever possible, if I need to use corticosteroids,
I prefer oral administration. Orally administered
prednisone or prednisolone only stays
in the pet’s body for 12 to 24 hours,
and the animal can be dosed on an as-needed
basis. This minimizes side effects, and
will not cause long term harm. In my practice,
I instruct people to use oral prednisone
or prednisolone only if the animal is
very itchy. I use the lowest dose possible
(much lower than most conventional doctors
use) for the fewest number of days. Corticosteroids
are never used if only minimal itching
is seen.
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