Use of prick-tests in the screening of immediate allergy to protein: 16 cases

Allergy to protein hydrolysates seem to be on the rise but screening is difficult because of the wide range of symptoms. The goal of our study was to improve the screening process by skin prick testing infants with an anaphylactic form of allergy to cow's milk.

We studied 92 infants who were allergic to cow's milk. The diagnosis was based on the results of skin prick tests, specific IgE assays, and oral food challenges. The skin prick tests were performed using a number of protein hydrolysate formulae and a synthetic amino acid-based formula available in France.

We detected sensitisation to the hydrolysates in 16 infants (17.3%), 15 by positive skin prick tests and one due to persistent symptoms on protein hydrolysate formulae (gastrointestinal manifestations, atopic dermatitis, and multiple food allergies), which completely receded when the synthetic amino acid formula was used as a substitute. Two infants had a positive hydrolysate oral food challenge test. There were no statistically significant differences in terms of age, sex, breastfeeding, clinical manifestations, family history, skin reaction size, or associated allergies. The infants who were sensitised to the hydrolysates had significantly higher specific IgE levels (whole milk,(_)-lactalbumin, and casein; median = 25.6 kU/L for cow's milk, p = 0.03) than those who were allergic to cow's milk but not sensitised to the hydrolysates.

Skin prick tests can be used to screen for sensitisation to hydrolysates in infants with IgE-mediated cow's milk allergy. They can also be used to determine the most suitable hydrolysate formula for individual infants.