Food allergies are an immune system disorder that makes it potentially fatal for affected individuals to eat foods that would be considered harmless by most. It is possible to be allergic to practically anything, but most food allergies are to proteins. Statistically most allergic reactions occur from ingesting or inhaling particles from one of the so-called "big eight" foods: peanuts, treenuts, egg, soy, wheat, fish, shellfish and dairy. Symptoms vary widely from gastrointestinal distress, hives and itching, to more severe reactions such as anaphylaxis, which impairs breathing and/or results in a serious drop in blood pressure and can cause death within minutes of exposure and for several hours afterwards. Type and severity of symptoms cannot be predicted even after an exposure has been observed. A food allergy is different from a food intolerance. A food intolerance is rarely fatal from a single, casual ingestion, and most usually causes gastrointestinal discomfort. Food allergies are triggered by an IgE antibody buildup which occurs after an initial exposure to the allergen. Subsequent exposure causes the body to release histamine. This can cause swelling of soft tissues, dilation of blood vessels, and fluid leakage from the bloodstream into the tissues. A particular concern is when ingestion inflames tissues in the throat and lungs, blood pressure drops severely, or fluid fills the lungs, potentially leading to death. Those afflicted with food allergies are also prone to environmental allergies (e.g., pollen, pollution) and are also prone to develop asthma. This section contains both health-related sites containing technical and medical information about food allergies, as well as non-technical, support sites and sites with information on how to conduct an allergen free lifestyle.