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McKesson Clinical Reference Systems: Women's Health Advisor 2002.2
Allergic Rhinitis
What is allergic rhinitis?
Allergic rhinitis is an allergic reaction of the lining of
the nose. Seasonal allergic rhinitis is also called hay
fever.
How does it occur?
Allergic rhinitis occurs when the nose and usually also the
ears, sinuses, and throat come into contact with
allergy-causing substances. The allergy-causing substances are
called allergens. The most common allergens are pollens,
molds, dust, and animal dander. Some allergens are present
only during certain seasons, for example, ragweed in the
fall. Others are present year-round, for example, the mites
in house dust.
When the lining tissues of the nose and sinuses come into
contact with allergens, a chemical called histamine is
released from cells in these tissues. Histamine causes the
nose lining to swell, itch, and produce excess mucus.
What are the symptoms?
Common symptoms of allergic rhinitis are
- itchy, runny nose
- sneezing
- nasal and head congestion.
Other possible symptoms include
- fatigue and lethargy
- itchy throat
- postnasal drainage.
How is it diagnosed?
Your medical history is usually the basis for the diagnosis
of allergic rhinitis. Knowledge of a family history of
allergic problems is also helpful. However, it may take
some detective work to figure out exactly what you are
allergic to.
Your health care provider may swab the lining of your nose
to obtain a sample of mucus. About 50% of people with
allergies have cells in their mucus that indicate allergy.
Tests for specific allergies may be performed. For most
people the best tests are skin scratch or prick tests. In
these tests your health care provider or an allergy
specialist places tiny amounts of suspected allergens under
your skin and looks for reactions. These allergy tests will
identify which of many possible allergens are causing your
symptoms. In some cases blood tests may be done to look for
antibodies to suspected allergens.
Because allergy tests are expensive, your health care
provider will probably recommend that you try treating your
symptoms with medication first. If medications do not
control your symptoms, allergy testing may be needed.
How is it treated?
The first principle of allergy treatment is to avoid the
allergy-causing substance. Air conditioners and special
filters can minimize the amount of pollen and mold that
circulates indoors. Try not to use an attic fan if you are
allergic to pollen. Putting plastic covers on mattresses
may help you avoid dust and mold. Pillows may also be
covered with plastic.
When environmental measures such as the ones described above
are inadequate to control symptoms, medication is usually
effective. Your provider may suggest that you first try
nonprescription decongestants for mild symptoms. Side
effects of the decongestants often include rapid heart rate
and insomnia. These medications can also raise blood
pressure of some people.
Nonprescription antihistamines are helpful, especially if
used only at bedtime because they may cause drowsiness.
Often the drowsiness will subside after you have taken the
antihistamine for 3 to 5 days.
Prescription antihistamines are usually very effective in
treating and preventing allergy symptoms. The new
"nonsedating" antihistamines do not usually cause drowsiness
and are taken once or twice a day. Some people take
antihistamines only on the days they are having symptoms.
Others start the medication at the beginning of their usual
allergy season and continue taking it until the season is
over.
It is safe to take antihistamines and decongestants together
if you have no medical reason not to take them together.
When antihistamines and decongestants do not sufficiently
control your allergy symptoms, prescription nasal sprays may
be added to your treatment. Two types of sprays are
available: steroid and cromolyn. Depending on a person's
other allergy symptoms, sometimes the nasal spray will be
the first and only medication required.
If your symptoms are severe in spite of medications, you
should consider getting allergy shots (immunotherapy).
Allergy shots will desensitize you to the substances that
cause your allergies. A mixture of the allergens identified
from your allergy tests is prepared. You then receive
weekly injections of this mixture. Usually after 4 to
6 months of allergy shots people begin to have relief from
their allergies. However, you will probably need to
continue the shots for 2 to 3 years or longer.
Proper treatment of allergy symptoms is the best way to
prevent complications of allergic rhinitis, such as ear and
sinus infections.
How long will the effects last?
If childhood allergies persist into adulthood, they will
likely be present for a lifetime. New allergies can develop
any time, even in previously nonallergic persons. Allergy
symptoms are dependent not only on season and weather but
also on location. Hence, your allergies may wax and wane,
depending on where you are living.
What can I do to help prevent allergic rhinitis?
There are no known ways to prevent the development of
allergic rhinitis. Once allergies have developed, you can
try to limit exposure to the things that cause them, for
example, pollens or animals. In severe cases, you may need
to move to another area, but you may develop allergies there
as well.
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