A fascinating Wall Street Journal Article on the difference between celiac disease and gluten intolerance, and how a non-celiac immune response to wheat might cause a variety of odd symptoms.
My own allergy developed in my mid-thirties, and is a full-on anaphylaxis response. Imagine my surprise the first time that happened! I also lost about forty pounds in the four months after I stopped eating wheat. I just throw that out there because I think that was part of my inflammation response to wheat, which I was eating every day (to calm down stomach problems! which were probably also caused by wheat!)
Anyway, responses to wheat can be varied and strange. I now encourage my family and friends to try stopping gluten for a couple of weeks, and see if they don't feel better overall. It doesn't help everyone, but you never know!