IVD has some great dog food such as Duck & Potato, Venison & Potato and Rabbit & Potato. Remember, anytime you try a new diet the results are not going to be instant. It does take time.
Heska labs has an allergy test, all your vet has to do is draw a blood sample and send it in...but it does take a few weeks.
Be The Kind Of Person Your Dog Thinks You Are.