Could also be hypothyroidism or staphylococcal infection. Vet really needs to scrape the area. Some people have tried putting on NuStock for different skin problems ( put on dog outside and let it dry before bringing dog inside ). Other sprays you can try include Vetericyn, Equisilver, Banix. You can also bathe the areas with an antibacterial and antifungal shampoo like Curaseb, Malaseb or Ketohex.