FOOD ALLERGY AND FOOD INTOLERANCE - WHAT IS THE DIFFERENCE

The literature is contradictory concerning the use (and misuse) of the terms ''food allergy'' and 'food intolerance.'' When using double-bli nd, placebo-controlled food challenge as the gold standard, the clinic al picture characterizing both diseases is identical, ie, concomitant signs and symptoms from the skin, gastrointestinal-tract and respirato ry system (classical allergic signs and symptoms). A distinction betwe en food allergy and food intolerance thus depends on whether the invol vement of the immune system can be verified. The basic problem with di agnostic tests such as skin prick test (SPT), measurement of specific IgE (RAST) or histamine release from basophils (HR) is that in contras t to inhalant allergens, no standardized extracts are commercially ava ilable. It is therefore often not possible to discriminate between the ability of a test per se in the diagnosis of food allergy and differe nces in allergen extract quality. This is probably the reason for the great variability in diagnostic sensitivity and specificity reported i n the literature. Many cases of food allergy to proteins may be theref ore misdiagnosed as food intolerance due to a low sensitivity of the t ests (SPT, RAST, and HR) used.