SEVERAL REVIEWS dealing with various aspects of sensitivity to cow's milk have been published in recent years.1-3 This report will point out why milk sensitivity is a complex subject not amenable to easy study or broad generalizations, and it will present a few emerging concepts based on laboratory and clinical observations.
Clinical sensitivity to cow's milk has been estimated to occur in 0.3% to 7% of all children.3 Thus, a significant number of sensitive subjects will be seen by the practitioner who cares for pediatric patients even though the vast majority of children may ingest milk without ill effect. Among the factors which occasionally seem to play important roles in the pathogenesis of sensitivity to cow's milk are age, infection, and, less frequently, emotional stress; genetic factors, however, may be a more basic cause than any of these. Laboratory studies have supported some of these theories by demonstrating