Allergies are an abnormal response of the immune system. People who have allergies have an immune system that reacts to a usually harmless substance in the environment. This substance (pollen, mold, and animal dander, for example) is called an allergen.
Allergies are a very common problem, affecting at least two out of every 10 Americans.
Allergies affect more than 50 million people in the United States -- the poor souls who sniffle, sneeze, and get all clogged up when face to face with the allergen (or allergens) that set them off.
For many, allergies are seasonal and mild, requiring nothing more than getting extra tissue or taking a decongestant occasionally. For others, the allergy is to a known food, and as long as they avoid the food, no problem.
But for legions of others adults, allergies are so severe it interferes with...
First, a person is exposed to an allergen by inhaling it, swallowing it, or getting it on their skin. After a person is exposed to the allergen, a series of events create the allergic reaction:
The body starts to produce a specific type of antibody, called IgE, to bind the allergen.
The antibodies attach to a form of blood cell called a mast cell. Mast cells can be found in the airways, in the intestines, and elsewhere. The presence of mast cells in the airways and GI tract makes these areas more susceptible to allergen exposure.
The allergens bind to the IgE, which is attached to the mast cell. This causes the mast cells to release a variety of chemicals into the blood. Histamine, the main chemical, causes most of the symptoms of an allergic reaction.
What Are the Symptoms of an Allergic Reaction?
Common symptoms of an allergic reaction to inhaled or skin allergens include: