I know it is possible to be allergic to only part of the egg, but even in cooking it is virtually impossible to separate the two, even if they are hardboiled (and the white & yolk both have proteins in them that can cause allergies- funny, I was just googling and it said that egg yolk allergies are more common in adults, who knew!). I suppose you could try it and see, but it would be hard to know for sure.