Allergy To Sheep Milk With Or Without Allergy To Cow Milk

Abstract

Cow milk protein represents a common food allergen in children. These children often look to other mammalian milks as nutritional alternatives, including goat milk and sheep milk. Previous reports suggest significant cross- allergenicity among the caseins of different mammalian milks. Isolated allergy to sheep milk protein is unusual, with only a few reported cases. We report the analysis of two cases of sheep milk allergy, one with concomitant cow milk allergy and the other without. Clinical and laboratory characteristics of two children with allergy to milk proteins evaluated at a pediatric allergy clinic were reviewed. Two-dimensional SDS PAGE and immunoblotting will be performed using extracts made from sheep milk and cow milk and serum from the two patients and appropriate controls. Subject 1 is a 10-year-old boy who experienced anaphylactic reactions to two sheep milk cheeses ( Romano cheese and ricotta cheese). He tolerates cow milk products. IgE ELISA for cow milk was undetectable (<0.35 Ku/L) and positive for sheep milk (29.2 Ku/L). Subject 2 is a 15-year-old boy with a long history of severe allergy to cow milk, who had IgE ELISA performed for several other mammalian milks. IgE ELISA was significantly elevated for both cow milk (34.1 Ku/L) and sheep milk (48.9 Ku/L). A high degree of cross-allergenicity exists between proteins from milks of different mammals, and this often limits dietary choices for children with clinical cow milk allergy. However, individual patients may display unique sensitization to a particular milk. These cases illustrate both these scenarios.