I was hoping to get a response back from you on my questions. However, I want you to have an answer as well. Normally when we see a dog with a yeast dermatitis which gives the skin that sour musty odor, it is due to an underlying reason. Basically any condition that causes a dog to scratch themselves to the point of damaging the skin will often lead to a yeast overgrowth. What happens is that the skin is damaged and the immune system is compromised and the yeast normally on the skin multiplies unchecked. A yeast dermatitis also is itchy so the dog scratches and they cycle continues.
So the underlying cause has to be found and corrected. Some underlying causes are fleas, mites (mange) or allergies. You asked about food so perhaps you already know there is the possibility of a food allergy. In that case, you want to choose a food that has limited ingredients and unique protein that the dog has not had before. Frequently this ends up being a "hypoallergenic" diet of say venison and sweet potato, or fish. You can see a lot of different foods here:
Wellness simple has a variety of different "flavors". Some foods do require a prescription as well. They seem expensive, but often the amount you feed is so much less that it ends up being quite cost effective in the long run.
Remember that once the allergen is identified and eliminated, it can take six weeks or longer to see improvement and of course, you still have to treat the skin infection with traditional shampoos, antibiotics and possibly an anti-inflammatory or anti-histimine as well.
I hope this information is helpful to you. If you would like any additional information or have more questions please don’t hesitate to press the reply to expert or continue conversation button so I can address any issues you still have . If you do find this helpful, please take this opportunity to rate my answer.