Patient Information
What are allergies?
Allergies are the incorrect or inappropriately strong response of the body’s immune system to foreign substances called allergens. Normally, the body does not recognize allergic triggers (usually proteins) present in certain types of food, pollen, dust and animal dander as harmful to the body. In people with allergies, the immune system becomes sensitive to these normally harmless substances and reacts as if these substances are harmful [Sanico and Valentine, 2003].
This sensitization to otherwise harmless substances can occur when such a substance gains entry into the blood stream. This usually occurs when these allergic triggers enter the body by means of the relatively thin lining of the nose, mouth, lungs, or the digestive tract thereby stimulating the body’s immune system to recognize this substance as “foreign”. The body’s immune system produces an antibody that attaches to the surface of specialized blood cells called mast cells. When these antibodies attach themselves to the mast cells, the body is then prepared to fight back the next time the allergen appears. When the next exposure occurs, the allergen sticks to the antibodies present on the surface of the mast cells [Sanico and Valentine, 2003]. This action results in the release of cellular chemicals such as histamine that, in turn, causes the typical symptoms of an allergy. The body’s response to these allergens is known as an allergic reaction. This over-reaction by the immune system is what distinguishes individuals with allergies from healthy people. Although a specific allergy is not usually inherited, the tendency to develop allergies is often inherited, thus if one or both parents have allergies, their children are also likely to have allergies [Wright, et al. 1994].
Allergies affect an estimated 40 million to 50 million people in the United States and is the sixth leading cause of chronic disease in the United States [Agency for Healthcare Research and Quality, 2002]. Additionally, allergies have been shown to interfere with day-to-day activities and lessen quality of life resulting in increased absenteeism and reduced productivity [Agency for Healthcare Research and Quality, 2002]. Allergies are responsible for a large financial burden on the healthcare system costing approximately 1.8 billion dollars/year for physician visits and medications [Agency for Healthcare Research and Quality, 2002].