Abstract • 9

Background. Cow's milk (CM) protein HFs appeared with the aim of decreasing or eliminating the allergenicity of CM proteins. Methods. To ascertain the prevalence of more or less severe reactions triggered by HFs, we have studied and meta-analyzed 37 studies, which have employed in 24 cases casein HFs (115 children, aged 20 days-15 years), and in 13 cases whey HFs (either extensively or partially) (82 children aged 1 month-15 years). Results. Considering the meta-analysis, HFs have provoked 197 reactions, most of which IgE-mediated, 115 to casein HFs (+ 2 localized) and 82 to whey HF, Among the 115 allergic reactions induced by casein HFs, there is 1 case of shock, 3 of anaphylaxis, 5 of systemic urticaria, 1 apparent life-threatening event, 13 respiratory reactions, 50 cases of vomiting and/or diarrhea, 3 of lip angioedema, and 17 abrupt recurrences of symptoms of HF resumption. Among the 82 reactions to whey HFs, there were 1 case of shock, one of pre-shock, 3 of anaphylaxis, 2 apparent life-threatening, 13 systemics, and 9 respiratory reactions, 9 cases of vomiting and/or diarrhea, 3 of lip angioedema, and 3 abrupt recurrences of symptoms of HF resumption. In comparison, soy protein formulas have provoked 1 case of anaphylaxis every 22,5 years. Sampson has proposed a 10-18% prevalence for HF allergy (in highly atopic children), however even 86% of neonates are recommended HFs (14% partially and 70% extensively), also in the absence of a complete history of family atopy. Conclusion. No HF is non allergenic, both for allergic children and for high-risk babies. Sensitization can be triggered by small amounts of HFs given high-risk babies in the very first days of life for prevention of IgE-mediated CMA.