about my dog? please help!

I know this is very odd to put on here because it's nothing to do with the app but we're all human and have lives and I'm sure some of us have pets. My poor baby keeps getting these balding spots all over his back and some of them have scabs on them.. we got him at 9 mon. old last November and they had told us it was common and just something pitbulls tend to get... but it's on and off and seems to never go away completely. They gave us a shampoo for him but I feel like nothing is helping.