Identification of a masked allergen, alpha-lactalbumin, in baby-food cereal flour guaranteed free of cow's milk protein.

We report on a baby food, cereal flour P (CFP), which, although guaranteed free of cow's milk protein, caused failure to thrive and diarrhea, vomiting, and coughing fits in a 22-month-old child. The purpose of this study was to identify the allergen involved. The investigation used prick tests, RAST, and the RAST inhibition method. Specific IgE was elevated to 100 kU/l for cow's milk and to 15.3 kU/l for alpha-lactalbumin (2.5 kU/l for casein, 0.7 kU/l for beta-lactoglobulin). Antibovine IgG IgEs were associated. RAST inhibition experiments demonstrated the presence of alpha-lactalbumin in "food-quality" lactose used in this flour, at a dose of 1-5 micrograms/g of CFP. The daily intake of alpha-lactalbumin was found to be less than 70 micrograms. This exquisite clinical sensitization was attributed to the intestinal hyperpermeability (IH) which favors the access of milk allergen to the blood, leading to an ever-growing state of hypersensitivity. It could have been due to egg- and mustard-associated allergies as well as to giardiasis and intestinal candidosis. This work underlines the risk of masked food allergens and the need of thoroughly informative labeling.