Hi T.,
What I recommend is for you to get a referral to a pediatric gasteroenterologist (GI) from your child's pediatrician. Ask him/her to refer you to one of the GI docs down at Children's Medical Center Dallas. After you make your appointment and go into the clinic, you will also be able to see THE BEST pediatric GI dietitian. Her name is Margareta Benser, and she has been working in pediatric GI for over 20 years. She does work part-time now, so when you make your appointment, ask to be seen on a day when she is there. You will not get any better care than from her. I know b/c I work with her. I am another ped dietitian there at Children's, but I work in another department.
Good Luck,
A.