Background: Products based on hydrolysed cow milk proteins or amino acid mixtures are recommended in children with cow's milk hypersensitivity. However, some children who are allergic to cow's milk and who clinically react to substitute milk formulas have been observed.
Objective: To determine the tolerance and allergenicity of protein hydrolysate or amino acid-derived formulas in children with IgE-mediated cow's milk allergy.
Methods: Twenty children with positive cow's milk challenges, positive skin prick tests and/or serum-specific IgE antibodies to cow's milk were selected. Oral challenges, skin prick tests and serum-specific IgE antibodies to extensively hydrolysed whey formula, partially hydrolysed whey formula, extensively hydrolysed casein formula and amino acid-derived formula were performed.
Results: Five out of 17 (5/17) children reacted to partially hydrolysed whey formula, (3/16) to extensively hydrolysed whey formula, (2/10) to amino acid-derived formula, (1/16) to extensively hydrolysed casein formula. Only extensively hydrolysed casein formula was tolerated by at least 90% (with 95% confidence intervals) of children. Hydrolysates provoked early and delayed clinical reactions, amino acid mixtures only delayed reactions. Partially hydrolysed whey formula elicited a significantly higher number of positive skin prick test reactions than other formulas. Two children had specific IgE antibodies to extensively hydrolysed whey formula, one to partially hydrolysed whey formula, one to extensively hydrolysed casein formula and none to amino acid-derived formula.
Conclusion: In this study, none of the cow's milk substitutes has been found to be non-allergenic. Our results suggest that in children with IgE-mediated cow's milk allergy, the first ingestions of extensively hydrolysed cow's milk protein formulas require strict medical supervision because of immediate reactions. This is not the case for amino acid-derived formula. Moreover, our data suggest that treatment of children allergic to cow's milk with cow's milk substitutes should be monitored for several days to document tolerance.