Normally, the human body defends itself against harmful substances such as viruses or bacteria, but, sometimes, the defenses aggressively attack usually innocuous substances such as dust, mold, or pollen. Each IgE antibody specifically targets a particular allergen the substance that triggers the allergic reaction. An allergic reaction may occur in the skin, eyes, lining of the stomach, nose, sinuses, throat, and lungs - places where immune system cells are located to fight off invaders that are inhaled, swallowed, or come in contact with the skin.
Allergies can affect anyone, regardless of age, gender, race, or socioeconomic status.
Generally, allergies are more common in children, however, a first-time occurrence can happen at any age, or recur after many years of remission. There is a tendency for allergies to occur in families, although the exact genetic factors that cause it are not yet understood. Often, the symptoms of allergies develop gradually over a period of time. Allergy sufferers may become so accustomed to chronic symptoms such as sneezing, nasal congestion, or wheezing, that they do not consider their symptoms to be unusual. Yet, with the help of an allergist, these symptoms can usually be prevented or controlled and quality of life greatly improved.