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What is an
Allergen? |
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RealVideo 56k
QuickTime |
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How does a
simple substance like a grain of pollen lead to runny noses and
teary eyes? Click above to find out what happens when your body
meets an allergen. |
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From sneezing
and wheezing to itching and tearing, allergies and asthma affect as many as
60 million people in the United States (more than 20 percent of the
population). When your body reacts to what is normally a harmless substance,
it "attacks" the allergen with a fusillade of weapons. The results can range
from mild congestion to death. A little bit of education and effort,
however, can go a long way to making your life free of allergic symptoms and
asthma attacks.
An allergy is an inappropriate response by the body's
immune system to a
substance that is not normally harmful. There are many types of allergies,
including food allergies, ragweed, pollen, mold spores, animal hair, and
certain metals.
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How
Allergies Work |
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RealVideo 56k
QuickTime |
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Ever wonder
what's going on inside your body when you have an allergic reaction?
Come inside with us and take a look. |
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Nasal allergies refer to the interaction of
allergens with cells within the lining of the nose.
What is going on in the body?
Allergens enter through the nose. Allergens include pollens, dust, dust
mites, mold spores, and animal dander. These substances interact with IgE
antibody on the mast cells inside the nose. This causes discharge of
histamine. Histamine causes sneezing, nasal congestion, and nasal discharge.
The mast cells also release other substances. These substances pull a group
of cells, called eosinophils, into the nasal lining. The eosinophils travel
into the lining of the nose over a 6- to 24-hour period. They then release
substances that can create additional symptoms hours after the original
exposure.
The first reaction is called the early reaction. The symptoms occurring
hours after the initial exposure make up the late-phase reaction.
For example, an individual who is sensitive to cats will develop an
immediate allergic reaction when exposed to a cat. This initial acute attack
may continue as long as the individual is exposed. Once the person leaves
the environment, the symptoms subside. Later, the release of eosinophils may
bring on another wave of the symptoms.
 Cause/Symptoms
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