How is the dog now, did the problem clear up?
I had a boxer a couple of years ago, who had a really bad skin infection and a ton of belly hair loss (not that boxers have much anyway!).
I changed his diet from the junk food (complete food, in dry form) I had been feeding him to raw diet only.
Along with this I tried a fungal cream for thrush (for humans) and the irritation did get better. However, as he had been fed complete food all his life, the change to raw food (cooked only) gave him a real bad upset stomach so I had to regulate it with complete food.
The rash returned, but only a little. He seemed ok with this. I continued with the cream and also natural yogurt treatment for the remainder of his life.
(he'd had ton's of anti biotics and steroids in the past, so I would not allow anymore of this type of treatment from the vet.
Have you tried a fungal cream?
AJ..
Dog Health Problems
