L.D.
I suspect that you may want him to be checked for food intollerances as well as allergies. Most M.D.s that I have seen won't do food intollerance testing. You may want to try a naturopath or homeopathic doctor instead. Or you can do your own little self testing. It's called the elimination diet (at least, I think that's what it is called).
What you do is eliminate the suspect food or ingredient from your diet for 3 weeks and then reintroduce it slowly into your diet. If you have an intolerance with that particular food, you may feel kind of crappy the first few days after you have stopped eating it because you are detoxing, and then you will feel fantastic. However, once you reintroduce the food, your symptoms reappear with a vengence, then you know that you need to stay away from that particular food/ingredient for a while longer. If eliminating and then reintroducing that food/ingredient causes you no problems whatsoever, then you know that you do not have an intollerance to it.
Hope this helps.