I used to hear that there was a great allergy/immunology clinic in OKC, but don't remember the name or know if it's still open.
You might want to try some other antihistamines and see if they work better, such as Zyrtec or Xyzal. You might want to try adding an H2 blocker, such as Zantac (150 mg. twice/day) or Pepcid (20 mg. twice/day) or take one of those in the a.m. and one in the p.m., which is what I do.
If you've started using a generic for Allegra, that could be the problem. There's some wiggle room as far as generics having to be identical to name brand drugs. Sometimes, though, antihistamines work for a while and then you need to try a different one.
You can ask your doc about trying some gastrocrom. It's pretty effective in about 80% of the people who try it for gi tract problems.
If you can post your symptoms, any testing you've had done, and any other conditions you have and/or meds you take, people will give you some ideas.
Are you on the low histamine diet? If not, here's a link to it:
http://www.urticaria.thunderworksinc.com/pages/lowhistamine.htmBe religious about it, and you might get some relief. Good luck!