First off, welcome to the site!
There are different hypoallergenic foods on the market.
Here is one that you might be interested in:
Potato&Duck Formula
More food
The only thing that put me off with these was the fact that the veggies where the first and second ingredient followed by the meat.
Those links were just from a brief search, but from quickly scanning the ingredients it looks like they are a good brand of food. Here is an Organic formula that doesn't contain wheat, corn, or beef:
Organic food
This looks like a wonderful food.
If you ask about the allergy-food problem in the Health Concerns forum, I'm sure you'll get a lot of helpful advice!