In the
body, antibodies are made by the immune system to substances that are
recognized as foreign. Each one is
specific to the foreign invader. IgE is
the type of antibody involved in allergic dermatitis.
These antibodies cover the surface of mast
cells found in the skin where they wait for contact with the specific
invader. When contact is made, the mast
cells release their chemicals in an effort to destroy the invader.
In an allergic animal, the whole immune
system is oversensitive to invaders and the release of mast cell chemicals
occurs inappropriately and in an extreme way.
There are
several types of allergies. The three
most common are flea allergy, inhalant allergy, and food allergy.
If the animal suffers from only one of these
types or a combination, the signs are generally the same.
Dermatologic symptoms are scratching, biting,
licking, chewing at feet, and reddened skin.
The dermatologic symptoms are the most common especially for flea and
inhalant allergies. Animals with food
allergies more commonly show dermatologic symptoms but can also have vomiting
and diarrhea.
Flea
allergies are very common in some areas more than others.
If you have a pet that is allergic to flea
bites, it only takes one flea to send the pet into a scratching fury.
The main area where fleas are seen are around
the base of the tail, lower back, and inside the hind legs.
The first line of defense in treating a pet
with flea allergy is controlling the fleas on the pet and in the environment.
Flea treatments do not just consist of
shampoos and collars any more.
Veterinarians are usually a good source for a complete armory of flea
control products for the pet and the environment.
Many animals with other types of allergies
can be made much more comfortable with minimal treatment once a flea allergy is
addressed and under control.
Atopy or
inhalant allergy is the most common cause of allergies in dogs and it can be
seen in cats as well. The causes of
atopy are as numerous as those for people.
Potential allergens include dust mites; molds; and grass, tree, and
flower pollens. Atopy may appear as a
seasonal problem initially and progress to a year-round problem as the pet
ages. Atopic dermatitis often appears in
the first two years of age.
Atopy may
be suspected after taking a complete history and making a thorough examination
of the pet, but diagnosis can be confirmed by skin testing.
Skin testing has been helpful because it
helps veterinary dermatologists identify specific allergens to which the pet is
allergic. Avoidance of the allergens
when possible is the best way to prevent allergies, but this is not always
feasible. Topical therapies such as
shampoos, rinses, and topical anti-itch solutions offer immediate but
short-term relief.
Avoidance
of the allergen is the ultimate treatment for the allergic pet, but it is not
always very practical. If the animal is
allergic to dust mites, regular cleaning of bedding and vacuuming should be
helpful. Pets that are allergic to
pollen can be rinsed down or wiped down with damp towels after they have been
out during high pollen times. In certain
areas, molds may be difficult to avoid by some pets because the molds are
ubiquitous. In other areas, molds can be
avoided by keeping pets out of damp rooms and using dehumidifiers during damp
times of the year.
Administration
of omega-3 fatty acids orally has been helpful in treating the symptoms of
allergies. Basically, they work by
helping to reduce the amount and effects of the mast cells and the chemicals
they release when confronted by foreign invaders and allergens.
Fatty acid therapy does not work for all pets,
but some animals will show a remarkable improvement.
One major drawback of fatty acid therapy is
that it does take several weeks before results can be seen.
Therefore, an owner must usually do some
other type of treatment in combination with the fatty acid supplementation.
Administration
of antihistamines can be particularly helpful for pets that have seasonal
problems or in combination with other treatments.
Use of antihistamines may be more beneficial
for cats than for dogs but this should remain an option.
Because different animals respond differently
to various types of antihistamines, several types can be tried before the
correct one is found. As in people,
antihistamines have similar side effects on pets such as sedation, dry mouth,
hyperactivity, and constipation.
Immunotherapy,
or hyposensitization, is another treatment option for pets, especially dogs,
with good results. It does require the
animal to undergo intradermal skin testing to identify the exact antigens to
which the pet is allergic. A
commercially prepared injection containing the exact antigens is then injected
into the allergic pet in a series over the course of weeks to months.
Treatment can be time consuming and requires
a dedicated owner and veterinarian, but it has been shown to have good results
and should be a serious consideration if the allergic pet has not responded to
any other conventional treatments.
Steroids
are an extremely useful tool when dealing with atopy.
They do have many unpleasant short- and
long-term side effects but like many other drugs, they can be very beneficial
when used correctly and at the lowest effective dose.
Steroids can be abused because they are so
good at controlling inflammation and making the pet feel better quickly.
Many people are lead to believe they are a
cure, instead of a short-term treatment option while other long-term treatments
are being sought.
Allergy to
a food ingredient is another type of allergy, and food allergies account for
about 10 percent of allergy problems in dogs.
Food allergies do not consistently respond as well as the other allergy
types to corticosteroids. The best way
to diagnose this type of allergy is to place the pet on an elimination
diet. This diet consists of a minimum
number of ingredients that are completely new to the pet.
The food should be comprised of ingredients
the pet has never had before, and it may be as simple as a lamb and rice
diet. However, it may need to be
something more novel such as fish and potato.
It is very important that this elimination diet be fed for eight to
twelve weeks with no additional treats or supplements that may interfere with
the trial. The supplements and treats
can contain hidden protein sources, such as flavorings, that may add potential
allergens.
If the pet
shows much improvement after the twelve-week period, owners can begin adding
back a former ingredient, roughly one each week, and watch for allergy symptoms
to return. If symptoms return after the
addition of an ingredient, it can be concluded that ingredient is the cause of
food allergy for that particular pet.
The best way to reduce allergy symptoms when food allergies are involved
is to avoid the offending ingredients completely.
More commercial diets are being made that
contain the novel ingredients and limited ingredients so that owners with food
allergy pets have more options.
If you
think your pet suffers from allergies, please see your local veterinarian.
If referral is needed to a veterinary
dermatologist, your veterinarian can do this to ensure that your pet receives
relief from the “itchies.”
