I haven't read the whole thread so apologies if I'm repeating anything. I have Crohn's disease - I was diagnosed aged 20, but had clear Crohn's symptoms from 12. HOWEVER I had bowel and other issues (juvenile arthritis) at a much younger age. When I was little it manifested as constipation, then went in the opposite direction later on.
Things like Crohn's can present atypically in children is my point. There is very little understanding of this among doctors.
Also, uveitis (inflammation in the eyes) can happen with Crohn's too so her eye issues could be connected to your daughter's bowel issues. Look out for joint pain and skin rashes which can also be connected.
Her eye issues could also be nothing to do with it and it be nothing even close to Crohn's!
Testing for Crohn's is quite invasive and best avoided if possible (colonoscopies etc), but they should do some bloods - ESR and CRP to look for inflammation, and maybe also test proteins and B12 levels to check for absorption issues. These aren't perfect and cannot diagnose or rule out something like Crohn's, but can inform next steps.
It took a long time for me to be diagnosed and along the way we considered:
- allergies to dairy (elimination diets take several weeks to show their effect (4-6) so skipping dairy for one day won't achieve anything. Also, elimination diets in children should always be supervised by a doctor so don't just cut stuff out on your own)
- tested for coeliacs (blood test is decent, but only a biopsy can fully rule it out)
- checked for bacteria (stool analysis),
- and also considered IBS.
The other thing is that bowel issues can be a sign or anxiety or other issues (e.g. abuse) in children, so please do check her general wellbeing and that she is safe. Sorry if that's not easy to hear, but it does need to be at least considered.
It should also be noted that ultrasounds are next to useless in these situations. They can rule out e.g. a mass or a blockage (good to know of course!), but give pretty much no further insight.
At 5 the priority will be not to hurt her through unnecessary testing and I do agree with that. Keeping a diary of food, symptoms, and what she's been doing each day will help to build a picture without testing though.