Anaphylactic or anaphylacticlike (anaphylactoid) reactions while dining occur with a disturbing frequency. These cases present as medical emergencies. The onset of symptoms may occur from minutes to two hours after ingestion. Some of the monosodium glutamate reactions (bronchospasm) may occur up to 14 hours later. Causative factors usually consist of food allergens (eg, peanuts), preservatives (metabisulfites), color additives (tartrazine), flavor enhancers (monosodium glutamate [MSG]), and food toxins (eg, scombroidosis). Understanding and diagnosing the cause of these reactions is extremely important to prevent recurrence and possibly fatal reactions. In addition, some of these color additives and preservatives are found in certain drugs and can cause similar adverse reactions.
Allergy to food antigens are IgE-mediated anaphylactic reactions, usually occurring within 30 minutes and up to two hours after ingestion. They are associated with a history of atopy and ingestion of known food allergens such as peanuts, egg, fish, and walnuts, together with