Food allergy: facts and fiction.

Hypersensitivity reactions to dietary products are especially common in the pediatric population, yet food allergy as a distinct clinical entity remains poorly defined. The clinicopathologic features of this syndrome can vary considerably from patient to patient; no reliable diagnostic laboratory tests are available, and some of the treatment regimens are controversial. The pathogenesis of this condition is not well understood. An important factor is the role of the intestinal mucosal barrier in the regulation of uptake of dietary antigen from the intestinal tract. Recently, significant differences have been observed between the features of the immature newborn and the mature adult intestinal mucosal barriers. These findings may be of fundamental importance to the pathogenesis of food allergy and are currently an area of intense research.