My DD continues to have digestive probs which she has had since birth but of the opposite nature to your child....runs and vomitting, being unsettled, colicky and distressed.I did think she was allergic to something in my diet but the tests were negative and I even changed her to formula because I was convinced that my milk was making her ill. I had tried eliminating certain food groups from my diet but this just made me unwell. When my DD started cows milk hypo allergenic formula she became constipated which I remedied as instructed by the CHN with a spoonful of sugar in a bottle of cooled boiled water. More recently in order to slow my DD`s gut motility after a bout of diarrhoea after determining that she did not have an infection a high fat diet was recommended by the paed. This worked well and eventually the runs stopped.
She has had more allergy tests done since starting solids which were again negative.
I began introduction of solids very, very cautiously but now I have relaxed and become much more confident.
I guess what I am saying is that I wondered if the constipating effect of dairy is due to it`s fat content and just takes a while for the body to adjust. I am no nearer to finding a solution to my DD`s probs but you may have just answered one of my questions.
I hope I have not offended you with this reply as I do know how hard it can be when your child is unwell and you just need to know how to help them.This is just our story and I don`t assume that it`s the same as yours all of our children are so very different.