These reactions do not involve the immune system and therefore are examples of food intolerance rather than food allergy. Most Americans consume a wide variety of food additives daily, with only a small number having been associated with adverse reactions. Most allergic reactions to food are relatively mild. Anaphylaxis is a rare but potentially fatal condition in which several different parts of the body experience food-allergic reactions simultaneously, causing hives, swelling of the throat and difficulty breathing. It is the most severe allergic reaction to an allergen.
Symptoms usually appear rapidly, sometimes within minutes of exposure to the allergen.
Because they can be life-threatening, immediate medical attention is necessary when an anaphylactic reaction occurs. Food Allergy Diagnosis usually begins with a thorough medical history, a complete physical examination and selected tests to rule out underlying medical conditions not related to food allergy. Patients may also have to keep a food diary and record symptoms over a period of time. Several tests are available to determine if a person is allergic to a certain food. In skin-prick testing, a diluted extract of the suspected food is placed on the skin, which is scratched or punctured.