I was diagnosed with collagenous gastritis 3-4 years ago and continue to fly to Boston from the Southeast US at least once a year. Working with my doctor, I have found a treatment that works well and he thinks through every treatment. Definitely worth a visit to see the specialist. Before seeing him, I had a hemoglobin that got down to 4 once and had more frequent episodes. I will say, my disease seems to present differently than most (massive and unpredictable upper GI bleeds so my treatment is likely much different than others).