I am not familiar with Nzymes. Do you have a holistic vet in your area? I have not been to any, but have heard raves about them. When my Ruby was having issues, we did not live in an area with a holistic vet. Once I switched my dogs to 'grain free' kibbles, their itchies stopped.
What is Rosie eating? One of the worse things is a dog food with corn in it. If my two eat corn, they will be shaking their heads and flapping their ears. Corn can cause lots of yeast in their ears.