My son's first reactions were at 3 weeks old.  Every morning he had hives on
his face that the Dr couldn't explain.  After we found out he is allergic to
milk I put it together.  It was from me kissing him.  I stopped putting milk
in my coffee and the morning hives went away.  He will still get hives from
touching surfaces or being touched by people where milk has been on their
hands or on the surface.  He has a milk free classroom at school.  His last
anaphylactic reaction was from food prepared where the person preparing the
food had recently handled cheese.  McDonald's will change gloves and/or wash
their hands before preparing your order when you request it.

E.J.