Advice, Opinions and Wisdom needed on Dog Allergies!?

If the Sweet Potato food works continue to use it. Sweet potatoes are in a different family than white potatos. Fleas can be detered, it sounds like your dog reacts to topical flea treatments, I would consider something like Program or Comfortis if your vet is comfortable with an internal prevention. I hear of people using Garlic but I know it can cause anemia, so I stay away from it. You don't mention whether your dog is long coated or short. A flea comb used daily will help too. Don't worry about smell left behind by shampoo, if you want to use aromatherapy you need to use essential oils as a base for a spray. Cats are just about more sensitive about everything than dogs.