what makes you think she might be gluten intolerant?

I have a gluten intolerance, as do numerous members of my extended family. everyone who has been tested for coeliac has come back with a negative result, but the gluten intolerance is very real.

many many doctors have absolutely no idea when it comes to gluten intolerance.
a food diary is a must, to take with you when you see someone. a doctor with an interest in food intolerance would be a good place to start, or get a referral to a dietitian or see a naturopath as they are more likely to have a working knowledge of food intolerance. if you don't think they know what they're talking about, then find someone you trust.