The use of extensively hydrolyzed protein formulas is the best alternative for children with cow's milk allergy, though cases of allergies to hydrolyzed proteins have been reported. The aim of this study was to clarify from our experience the diagnostic, evolutive and therapeutic aspects of allergies to extensively hydrolyzed protein formulas.
We report eight cases of allergy to extensively hydrolyzed protein formulas seen between 1985 and 1998. The diagnostic criteria for allergy were either the appearance of immediate anaphylactic reactions after the ingestion of protein hydrolysate or a positive challenge test with the protein hydrolysate.
Four children developed immediate anaphylactic symptoms after ingesting protein hydrolysate, and four children demonstrated subacute or chronic gastrointestinal symptoms. All children who developed acute anaphylactic symptoms had positive skin tests and specific IgF, antibodies (RAST) to cow's milk and/or hydrolyzed proteins. Conversely, in the four children with chronic gastrointestinal symptoms, skin tests and specific IgE antibodies were negative in three cases, but intestinal histology was abnormal in all of them when they were fed with a protein hydrolysate; this became normal after excluding the hydrolysate (data available in only two cases). Three children tolerated another protein hydrolysate form (whey vs. casein), four children had a favourable outcome when fed with human milk, and an amino-acid-based formula was successfully used in the most recent case. Nonhydrolyzed cow's milk proteins were tolerated after the age of 18 months in six children. Other atopic symptoms were observed in six children.
Allergy to cow's milk protein hydrolysate is rare. The diagnosis is usually easy in children who develop acute anaphylactic symptoms, though intestinal histology is generally necessary for the diagnosis of allergy with chronic gastrointestinal symptoms. Treatment is based on the use of either another protein hydrolysate form (whey vs. casein) or an amino-acid-based formula.