It is very common for someone to complain about adverse reactions to particular foods. These adverse events can be categorized into three groups – 1) food allergies, 2) immunologic intolerances, and 3) non-immune mediated intolerances. So what is the difference? Food allergies are adverse events characterized by an IgE (antibody) response. They are the serious and life threatening kind and are fortunately relatively rare. Immunologic intolerances are immune response related but don’t produce IgE antibodies. Examples are celiac disease. Finally non-immune mediated intolerances is the catch phrase for the common gastrointestinal problems that are widespread such as lactose intolerance. The article below provides a more complete description of each condition.
http://allergies.about.com/od/foodallergies/fl/Food-Allergy-versus-Food-Intolerance.htm