Allergy Information
What are
Allergies?
How Allergies
Develop
The Histamine
Connection
Pollen and
Allergies
Seasonal Allergic Rhinitis or
Hayfever
Perennial
allergies
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.
- Look for typical Allergens Where You Live
- You can view the Pollen and Weather Forecast to see how your allergies may be affected within the next few days or we can tell you prior to high levels in your area when you Subscribe to the Pollen Alert
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!
