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What are Allergies?
Simply put, an allergy is a response by your body to
something that is ordinarily harmless. The purpose of the
immune system is to recognize harmful infection-causing
invaders and to get rid of them. However, for some people,
the immune system overreacts to ordinarily harmless
substances like indoor allergens such as pet dander,
pollen, dust, and mold and outdoor allergens such as
pollen from grass, trees and weeds. These people have
"allergies." Their bodies attempt to expel these
ordinarily harmless substances, causing sneezing; a runny
nose; itchy, watery eyes and sometimes hives.
How Allergies Develop
Why do you develop allergies? Nobody knows for sure,
although the tendency to develop allergies can be
inherited from your parents. If one parent has allergic
disease, the estimated risk of the child to develop
allergies is 26%. The child's estimated risk grows to 52%
if both parents have a history of allergy.
Scientists do know how a person develops
allergies. The first thing that happens is you are exposed
to a particular substance-for example, pollen from a
ragweed plant. This substance makes its way to your nose,
where your immune system detects it and, considering it a
harmful invader, creates antibodies to fight that
particular substance. These antibodies stay in your
system, prepared for the next time they encounter that
same allergen.
The Histamine Connection
The next time you breathe ragweed pollen in - and every
time after that - your body will manufacture more
antibodies to fight it off. The antibodies stimulate cells
("mast cells") in the linings of your nose,
eyes, throat, and lungs to release a chemical known as
histamine. Histamine attaches to nearby blood vessels,
causing them to swell, and secrete more fluid than usual.
Histamine can also irritate nearby nerve endings, causing
itching. Ultimately, histamine causes symptoms such as
sneezing; itchy, watery eyes, and a runny nose. These
symptoms are simply your body's attempt to expel the
pollen it wrongly assumes is dangerous.
Pollen and Allergies
Nearly 50 million Americans have some form of allergy. For
some of these people, symptoms come and go with the
pollination seasons of certain trees, grasses, or weeds.
Pollen levels from these plants can vary day to day,
depending upon several factors, including the weather.
High pollen levels can, in turn, affect the severity of
symptoms you experience. Seasonal allergies affect about
35 million Americans.
Allergic Rhinitis
The term "allergic rhinitis," when translated,
literally means "inflammation of the nose." (The
term "rhinitis" is derived by combining the
Greek word for nose ("rhinos") with the term
"itis," which means inflammation.)
Seasonal allergic rhinitis has also been
referred to as "hay fever," which is very
misleading considering the fact that it has nothing to do
with hay or a fever. Dr. John Bostock, a British physician
who suffered from allergies and noted a correlation
between his symptoms and the British haying season, coined
the term in the early 1800s.
Perennial allergies
When allergy symptoms are caused by year-round allergens,
the condition is termed "perennial rhinitis."
Important allergens that should be avoided
include the following:
-
Dust mites, specifically mite feces,
which are coated with enzymes that contain a powerful
allergen. These are the primary allergens in the home.
-
Animal dander (flakes of skin) and
hair, including from cats and dogs. Cats pose the
greatest risk of all common pets.
-
Molds
-
Cockroaches are major allergy triggers
If you suffer from allergies, it is
important to keep in mind that your symptoms may be caused
by more than one substance-or a mixture of both perennial
and seasonal allergens. In fact, that's why it can be
tricky to avoid the things that trigger your allergies! |
