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Food allergy
Make it clearer
Food allergy is a reaction of the body's defense system against something that should be harmless: the proteins in a food. Instead of tolerating them, the body treats them as if they were invaders.
The best known form happens in two stages. First comes sensitization, the first time around: cells called dendritic cells show the food protein to the immune system, and in response the body makes antibodies of the immunoglobulin E type, defense proteins tailored to that food. Those antibodies do not stay floating around: they attach to the surface of mast cells and basophils, two cell types of the defense system.
The second time is the reaction. When the person eats that food again, the protein binds to the antibodies that were already waiting, and the cells release histamine and other inflammatory substances. That makes smooth muscle contract, blood vessels widen and more mucus form. What shows up ranges from urticaria, the welts on the skin, to anaphylaxis, a whole-body reaction that can be life threatening.
In brief
Food allergy is an abnormal immune response to dietary antigens, and it may or may not be mediated by immunoglobulin E.
The body treats a food as if it were an invader.
In the immunoglobulin E mediated forms, sensitization begins with antigen presentation by dendritic cells and ends with antibodies bound to mast cells and basophils.
Re-exposure to the food releases histamine, with smooth muscle contraction, vasodilation and more mucus; symptoms range from urticaria to anaphylaxis.
Sources (1)
- National Center for Biotechnology Information, StatPearls PublishingFood Allergies, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated