The classic allergic reaction, which is classified as the type-1 hypersensitivity reaction, can be elicited by food, but this is fairly uncommon. When we discuss food sensitivities in ADHD we are discussing a different, not well-defined, mechanism.What are allergies? According to Wikipedia, "an allergy is a condition of hypersensitivity to a substance (an allergen) considered harmless to most people." Hmmm, most people? In fact, 50 million Americans are estimated to have allergies.Allergy is basically a Greek term which means "other work". The term allergy is used to describe a response, by the body, to a substance, which is not necessarily harmful itself, but results immune responses and reactions that causes symptoms and disease in a predisposed person, causing inconvenience, or a great deal of misery. It occurs when the body's immune system overreacts to normally harmless substances. It is a popular form of immune reaction which creates the process of irritating the body through means of itching. Allergy is a common disorder which is virtually affecting more than 50% of the total world population in one way or the other. By allergy the immune system reacts against a substance that it is not supposed to react against, and the reaction is often exaggerated.Mold is pesky little fungi that loves to grow in warm, moist, dark places. Mold releases spores into the air, and when mold is touched or the spores are inhaled, they cause inflammation in the airways and bring on an allergic reaction. It is important to have your house routinely checked for mold, especially if you live in a humid climate. The longer a mold problem persists, the harder it is to eradicate.Boehncke, et al. from the University of Frankfurt reported in 1998 that certain white blood cell types known HLA class II genotypes or HLA DQ and DR genetic patterns were found more frequently in people with certain pollen associated food allergies. HLA-DQB1*0301 is present in more people with grass pollen allergy. Those with HLA-DRB1*08, an inherited white blood cell protein pattern linked with a grass pollen allergy, have six times the increased risk of peanut allergy. Although food allergies cannot be prevented, the best way to defeat it is by staying away from the food a person is allergic to. Making the right diagnosis on food allergy versus food intolerance can be tricky.Welcome to the world of food allergies and intolerances.