Allergy to extensively hydrolyzed cow milk proteins in infants: identification and treatment with an amino acid-based formula.

We report on 13 infants allergic to extensively hydrolyzed protein formulas (EHFs) who were first seen with chronic digestive symptoms. Feeding with an amino acid-based formula decreased symptoms and improved weight gain. A challenge with EHF produced positive results in all these infants. Allergy to EHF must be considered in patients who are allergic to cow milk and have persisting symptoms on an EHF diet.