Hello Allison, @alison486, and welcome to Mayo Connect,
I am sorry to hear that you daughter is ill with Collagenous Gastritis (CG), while I don't have that disorder myself, I have a lot of digestive tract problems and I understand how difficult they can be. Such as appetite problems, weight loss, etc.
We do have a number of Members who have discussed their children who have CG. I will ask a moderator (@colleenyoung, @kanaazpereira or @lisalucier) to move your post to the discussion of Collagenous Gastritis. Until then you can read about others with CG at this link, https://connect.mayoclinic.org/discussion/collagenous-gastritis/?orderby=DESC#chv4-comment-stream-header
In this discussion group you can meet @motherkat, @wendyt2018 and others who have recently posted about children, like your daughter, with CG.
If you are comfortable sharing more, could you tell us about your daughter's most difficult symptoms right now?
Thank you it is good to hear there are others. To our knowledge H is the only child in the uk with it. She has had it for 5 years starting with severe symptoms of anaemia and progressing to acute sudden bout of vomiting violently with severe blood loss every 9-12 months. Luckily she is pretty stable now but it would be lovely to hear that hopefully she will grow out it maybe fingers crossed. So little is known about it here. A