Anti-Yeast Baths and Rinses.
If your dog has Yeast overgrowth on her skin, I recommend disinfecting her entire body with a natural, anti-fungal shampoo.
Oatmeal is a grain which provides a food source for that Yeast on your dog's skin.
Use an anti-fungal shampoo made from, for example, tea tree oil or an herbal blend.