Chron's disease, I believe, can develop in a person eating gluten and suffering from undiagnosed celiac's disease.
It sounds like your daughter could benefit from going gluten free. I hear enterolabs does a stool test that is highly regarded by those who had difficulty getting a dx with traditional blood tests. If you need to know get the testing done asap and then begin the diet. Otherwise, I would suggest just starting the diet and 'see how it goes'--
We are gluten free 9 months now in our house and ds is doing fantastic. Does your daughter also suffer from tics at all? I am just wondering because ds was dx'd with a tic disorder last year and it is virtually non-existent now due to the diet.
June