Aspirin and food dye reactions.

FOOD reactions as a cause of illness were recognized as early as the first century B.C. by Lucretius, who observed that "one man's meat is another man's poison." Over the subsequent years it has become obvious that this poison may take the form of infection, toxic reaction, pharmacologic (as in the "Chinese restaurant syndrome" due to monosodium glutamate), enzyme deficiencies (such as lactase), and allergic reactions. The word "allergy" was first suggested by Von Pirquet' in 1906, but, unfortunately, there continues to be disagreement as to its definition. This had undoubtedly contributed to the confusion concerning adverse reactions to foods and environmental chemicals. The term "allergic" was first used by Von Pirquet to define an "observable altered reaction to environmental substances." By this definition no immunologic mechanism is implied. It should be recognized, however, that when he used the term "allergy" he described the state opposite to immunity. Studies up to that time demonstrated an immune system that protected individuals from the lethal effects of infection, but that on occasion the immune system could result in reaction adverse to the host. The terms that were used to define these adverse immunologic reactions were anaphylaxis (removal of protection) and allergy (meaning a state of altered response). As the immunologic basis for some of these reactions became more apparent by the use of direct skin tests, passive transfer skin tests, and challenges, a group of physicians, including Hansel, Coca, and, more recently, Rinkel and Randolph, preferred the broader definition of allergy, which did not imply an immunologic reaction to describe adverse reaction