Natural history of cow milk allergy: clinical outcome.

Of an initial cohort of 100 children with challenge-proven cow milk allergy, 97 were reviewed after 5 years to determine the effect of prolonged cow milk avoidance on clinical features, the reported frequency of adverse reactions to other foods, and the reported emergence of other atopic disorders. The mean age at diagnosis was 16 months, and at final follow-up 99 months. Cow milk tolerance by challenge was demonstrated in 28% of patients by 2 years of age, 56% by 4 years, and 78% by 6 years. Only 25% of children were allergic to cow milk alone; parents reported associated adverse reactions to many other foods, including egg (58%), soy milk (47%), and peanut (34%). Exclusion of cow milk from the diet of infants and young children with cow milk allergy did not prevent the subsequent development of atopic disorders. At final follow-up, 40% of patients reportedly had asthma, 21% atopic eczema, and 43% allergic rhinitis. It is unclear whether independent mechanisms control the development of cow milk allergy and other atopic conditions.