Have you considered going to a veterinary dermatologist? What you are describing doesn't sound like food allergies to me either, but rather some type of fungal infection of the skin.
Here are a couple around the Atlanta area:
Atlanta Veterinary Skin & Allergy Clinic Home Atlanta Animal Allergy and Dermatology™ | Home |
The Veterinary school at UGA might be able to point you in other directions, too.