I have a year old female bulldog who actually seemed to have the same thing. My vet gave her a steroid shot, two weeks of antibiotics, anti-fungal shampoo & leave in conditioner. My vet told me it was a skin infection from a bunch of fire ant bites she had gotten prior & just scratched too much. It seemed to work perfectly for my dog. I was also told to try coconut oil on their skin & scoops in her food. The shampoo & conditioner worked great!