Formula allergy and intolerance.

There are two major types of adverse reactions in infant formulas: (1) formula allergy/hypersensitivity, which is an immunologic response, and (2) formula intolerance, which is a nonimmunologic response. Formula intolerance can occur in infants with an underlying congenital or acquired enzyme deficiency (disaccharidase deficiency, galactosemia, hereditary fructose intolerance). The clinical presentation, diagnosis, and treatment of both reactions are reviewed in this article. The appropriateness of the use of a variety of infant formulas is discussed. Guidelines for the prevention of allergic disease are described as well.