Jack was possibly allergic to dairy until he was about 12 months. He was actually ok with cheese and my breast milk, but yoghurt caused a reaction. We have since discovered he has a sulfur allergy though so now I'm thinking it might have been to do with the fruit in the yoghurt and not the dairy. He can eat fruity yoghurts now without a problem so who knows. The good news for you is that most dairy allergies disappear around 1 year.