A follow-up study of infants with adverse reactions to cow's milk. I. Serum IgE, skin test reactions and RAST in relation to clinical course.

47 infants with cow's milk sensitivity were followed for a period varying between 6 months to 4 years (mean 28 months). The age at onset of symptoms varied between 14 days to 20 months. The clinical course was studied in relation to reaginic allergy by use of serum IgE, skin prick test and RAST. Infants with an immediate onset of symptoms from the gastrointestinal tract and the skin after cow's milk intake were discerned as a distinct entity having a high frequency of atopy in the family, positive skin tests and positive RASTs to milk (71%). Cases with delayed reactions to cow's milk seldom had a positive RAST or skin test. Most infants of both groups showed an increasing tolerance to milk. In RAST positive infants the RAST-titers increased significantly after onset of symptoms. After having reached a peak the titers subclined in several cases. The titers did not reflect the degree of milk sensitivity during the follow-up period. However, infants who developed high titers seemed to develop tolerance more slowly than infants with low titers.