The role of sensitizing proteins in milk allergy

In clinical allergology and particularly during childhood, we quite frequently encounter patients who are allergic to milk. This has usually been confirmed by the clinical history and by skin testing. Statistics show a sensitization to cows' milk of between 0.3 and 7% of the world's population. In view of the diversity of opinions about an immunological problem of such clinical importance, we decided to carry out a clinical study to determine the sensitization to different fractions in patients allergic to milk. For this study, 82 patients were selected with a history of milk allergy together with strongly positive (++++) skin tests. Simultaneous intracutaneous tests were also performed with Alpha-lactalbumin, Beta-Lactoglobulin and Casein. The following points summarize our conclusions. 1. In milk allergy, lactoglobulin is the fraction with the greatest sensitizing potential (76.8% of our cases). 2. The alpha-lactalbumin fraction sensitized 59.7% of our cases, but gave weaker positive reactions. 3. Casein is the least sensitizing of the fractions studied, affecting 42% of the patients. 4. Taking into account that many patients with a positive history of milk allergy may show negative reactions when tested with whole milk and positive reactions to one of the three fractions discussed, it would be advisable to test routinely with these three fractions as well as with whole milk.