A case of anaphylaxis caused by whey protein drink in a 14-year-old boy who was able to consume processed foods containing milk but did not recognize whey as milk protein

Abstract

There are many reports that casein is the main allergen in cow's milk allergy, and cases of sensitization to whey alone are limited. While casein is heat-resistant, whey is known to lose its antigenicity due to structural changes caused by heating, and there is a discrepancy in antigenicity of whey between unheated milk and milk-containing processed foods. In this case, a child with milk allergy who could consume milk-containing processed foods did not recognize whey as milk protein and developed anaphylaxis after consuming a whey protein drink. The patient was a 14-year old boy who had anaphylaxis to bread porridge at 6 months of age and was diagnosed with milk allergy. He had received oral immunotherapy using unheated milk at another hospital, and was able to ingest 100 mL of unheated milk two years ago, but had discontinued it voluntarily a year ago. However, he consumes processed milk products, such as bread and cheese, on a daily basis. On the day of his visit, a friend recommended a whey protein drink on his way home from school, and immediately after taking his first sip, he developed a cough and shortness of breath, which led to his visit to our hospital. Tests conducted after his visit revealed that he had a whey allergy. In this case, he was able to ingest baked milk without any problems. One of the causes of the symptoms was failure to recognize the antigenicity of whey. Identifying the causative allergen in milk allergy is important for diagnosis and treatment.