New aspects of diagnosis of milk allergy in children.

In clinical practice at present, milk allergy may be suspected by medical history, skin testing, or RAST. None of these procedures has shown an optimal correlation with the result of challenge testing. The obvious need for better diagnostic tests has stimulated numerous attempts to improve the current tests and to develop new ones. The use of individual milk protein fractions for skin testing or RAST has not shown superiority over using whole cow's milk. Lymphoblast transformation and leukocyte inhibition factor production have shown low specificity. The few studies on neutrophil chemotactic activity have shown contradictory results. Morphometric and immunohistochemical studies of small intestinal biopsy specimens seem to be more suitable for research studies than for routine clinical practice. The reliability of in vitro tests on cultured intestinal epithelium remains to be verified and is far from being applicable in clinical practice. The diversity of immunologic mechanisms of milk allergy is largely responsible for the difficulty encountered in developing a highly reliable test in the diagnosis of various reactions to milk allergy.