Allergy to eggs is one of the most common food allergies in children. More than half of the children outgrow their egg allergy before adulthood. Egg white contains the main egg allergens. The eggs of other poultry, such as ducks, are very similar to those of hens and can cause reactions in egg-allergic individuals.Allergy to eggs is one of the most common food allergies in children. More than half of the children outgrow their egg allergy before adulthood. Egg white contains the main egg allergens. The eggs of other poultry, such as ducks, are very similar to those of hens and can cause reactions in egg-allergic individuals.