So the Canidae wasn't the answer.
I took a look back on my notes and records of all the different things I have tried with Roxy and realized I could not correlate her reactions to food changes, environmental changes, shampoos, anything. It seems like the symptoms ebb and flow on their own schedule.
So I decided to take Roxy to a different vet. I found out about a vet here that practices holistic veterinary medicine in addition to traditional veterinary medicine. She believes Roxy suffers from Atopic Dermatitis which is similar to human eczema. It is a stand alone disease, and could
be inflamed by food or environmental allergies, but not necessarily caused
by allergies. The vet said Roxy may or may not have any specific food allergies as it is hard to tell while Roxy is on a kibble diet. She says there is no real cure for the disease, but it can often be controlled or improved by feeding unprocessed foods, improving whole body health, and treating symptoms as they occur.
So the vet told me to start by getting Roxy onto an unprocessed diet with a good vitamin/mineral/omega supplement and then revisit Roxy's condition in 6-8 weeks. She says Roxy's condition is on the mild side of moderate (at this moment) and believes we can improve Roxy's condition without medications at this point. This is good to hear. She sent me home with some McKillip's Ear Cleaner and Nizoral anti-dandruff/fungus shampoo to use when needed to treat seborrhea/rash.