Allergies are exaggerated reactions of the immune system to substances that, in the majority of people, cause no symptoms. Symptoms of the allergic diseases may be caused by exposure of the skin to a chemical, of the respiratory system to particles of dust or pollen (or other substances), or of the stomach and intestines to a particular food. This immune overreaction can results in symptoms such as rashes, hives, lower blood pressure, difficulty breathing, coughing, sneezing, itchy eyes, runny nose and scratchy throat.
These overreactions by the body result from an aberration somewhere in the normal immune process. The exact causes of these allergic reactions are not always apparent, however, many studies have been conducted with with varying validity and acceptance that point to possible genetic as well as environmental components.
