DS has had anaphylaxis to cows milk as a baby and so has been dairy free. He has just had a skin prick test which was negative, so we were hoping to start challenging. However the IgE then came back positive (35) so have been advised not to. I understand that false positives are more common than false negatives, so am a bit frustrated. Any ideas why the skin prick could be wrong, or thoughts on what we should do?