We did skin prick tests on dd#1 a few months ago, as she had always had eczema and asthma was starting to be a problem too. We found she was allergic to wheat and dustmites, among others. Wheat came as a real surprise to us, as we had no clue it could be a problem for her, she loved bread, pasta, cookies ....
We have taken wheat out of her diet and still see no improvement, but I saw the reaction, so we know we can't go back (yet).
Anyway, just to let you know that:
a) the culprit may be something you are not expecting
b) sometimes you can't really see improvement but it is there
Best,
Sara