Extensively hydrolyzed formula (MA-mi) induced exacerbation of food protein-induced enterocolitis syndrome (FPIES) in a male infant.

BACKGROUND Food protein-induced enterocolitis syndrome (FPIES) is a severe, cell-mediated food allergy in which digestive symptoms such as severe vomiting and diarrhea are induced by cow's milk and/or soy protein in infants. Generally, a food-specific IgE is not detected, and FPIES may be caused by inadvertent exposure to allergenic foods. CASE SUMMARY The patient in our case was a male infant in whom vomiting had been induced by ingestion of a cow's milk-based formula and bloody diarrhea had been caused by ingestion of breast milk during the neonatal period. Accidental ingestion of a new and extensively hydrolyzed casein/whey formula, MA-mi, caused watery diarrhea at 8 months of age, and FPIES was diagnosed based on these symptoms. In antigen-specific lymphocyte stimulation tests, New MA-1 was negative, but MA-mi and cow's milk antigens were positive. The only causative antigens were derived from cow's milk, and the symptoms were not induced by another extensively hydrolyzed casein formula, New MA-1. The patient grew and developed normally thereafter, and no symptoms were induced by solid food during the course of the condition. DISCUSSION MA-mi is likely to be used increasingly for allergic infants, but it is not necessarily a substitute for other hydrolyzed milk formulae in all cases, and care should be taken regarding its use and possible misuse.