Effect of cow's milk on the gastrointestinal tract: a persistent dilemma for the pediatrician.

The confusing area of cow's milk intolerance is explored in an attempt to define the various mechanisms whereby milk affects gastrointestinal function, resulting in clinical symptoms (diarrhea, vomiting, gastrointestinal bleeding, etc.). The adverse reaction of infants to cow's milk ingestion may relate to lactose intolerance (enzymatic), a direct toxic reaction to the mucosal surface resulting in epithelial damage, or it may be immunologically mediated. Factors such as increased intestinal permeability to milk proteins during the newborn period may also contribute to susceptibility of young infants to milk sensitivity. The relative roles of systemic (milk agglutinins) and local immunity (SIgA antibodies) in milk intolerance are discussed and differential immunologic responses (IgE versus IgA/IgM) considered in the pathogenesis. It was concluded that new techniques such as organ culture of intestinal biopsy specimens are needed to establish the diagnosis of hypersensitivity and to begin to provide ways of adequately treating the condition.