What is an allergen?
|Michael R. Rupp, MD.
FAAAAI, FACAAI, Board Certified Allergist & Immunologist
About the author: Dr. Rupp is a board certified allergist immunologist who believes in providing current, up to date, FDA approved, therapy to patients in the best way possible for them.
Simply stated an allergen is anything that the human body is exposed to that results in the formation of an antibody called IgE. When enough IgE has attached to an allergen this results in release of histamine and other substances from mast cells and results in symptoms of allergies.
Allergens are usually proteins that have a complex enough shape to present a unique 3 dimensional structure to the body. This shape remains stable despite absorption into the body, exposure to stomach acid (in the case of food allergies), or other attempts at destruction of the protein. In some cases an allergen causes problems In its native or raw form but does not after extensive heating. This has been shown to be true for egg and milk protein. Allergens can vary from pollen grains, to mold spores, to dust mite feces, to the shed skin cells of animals (dander).. Allergens must be small enough to be absorbed into the body.
Allergens are not non-biological. For example people who are allergic to dust are not allergic to dirt, they are allergic to things in indoor dust like dust mite feces, animal dancers, mold spores, etc. Other items that are not allergens are chemical residues in the environment. Things like bleach, perfume, cleaning products, etc. While these may cause sneezing, drainage, and other respiratory symptoms, this is caused by irritation, to the nose, throat, md lungs, not by formation of IgE antibody.
Allergens that commonly cause problems for people may differ by where you live. There may be more mold in areas that are wet, more dust mites in costal areas and less in arid high altitude areas. Common allergens throughout the United States include ragweed, dust mites, cockroach, Bermuda grass, and many others.