Food allergies: Causes and symptoms

A food allergy is an adverse reaction to food involving an immunological mechanism. It typically occurs within the first few minutes to two hours and can produce the sudden onset of itching, hives (urticaria), swelling of the face, tongue or back of the throat that may be accompanied by difficulty breathing and/or light headedness and hypotension.

Most food allergies are due to specific proteins found in foods. Some people are so sensitive to certain proteins that eating that protein could cause sudden death. The foods, which cause the most severe reactions and most cases of food allergies are: cereals containing gluten, crustacean, eggs, fish, peanuts, soybeans, milk, and tree nuts.

The common mechanism leading to various food allergies is the lack of immunologic and clinical tolerance to an ingested food, which results in immediate or acute reactions mediated by specific antibodies, namely immunoglobulin-E (IgE), or delayed clinical disorders through specific immune cells.

Food allergy remains the principle safety concern for foods derived from recombinant DNA. These genetically modified foods contain newly expressed proteins that may present a risk for the foodallergic individual.
Food allergies: Causes and symptoms