A food intolerance is possible.
As to celiac, it should be tested for with blood tests before any diet modification is done.
A pillcam is best for finding small bowel inflammation and is typically only done when Crohn's is suspected but colonoscopy and endoscopy and perhaps MRI or CT scans have all been done and are inconclusive.
As to microscopic colitis, it usually occurs in elderly people (though not always), more likely in older women than older men, and usually presents with watery diarrhea.
It would be quite unusual for it to be IBD with normal blood work AND normal fecal calprotectin, but it's still possible.
Post Edited (beave) : 4/2/2019 3:30:33 PM (GMT-6)