What are Allergens?

An allergen is a type of antigen that produces an abnormally vigorous immune response in which the immune system fights off of a perceived threat that would otherwise be harmless to the body; such reactions are known as allergies. When an allergen that a person is sensitive to is present, the person's immune system overreacts by producing allergic antibodies. These antibodies travel to cells that release chemicals, causing an allergic reaction.

This reaction usually causes symptoms such as sneezing, stuffiness, runny nose, or itchiness to the nose, roof of mouth, throat, eyes, and/or ears. As sensitivities vary widely from one person to another; a very broad range of substances can be allergens to sensitive individuals.