I'm a pit owner, I've had many Pits but never this problem, it really isn't breed specific. It does sound like it is due to cold/dry weather. I would make sure he is getting enough omega fatty acids and supplement with grizzlys salmon oil to help with that. This will help his skin be healthy, not dry and flaky and take away the horrible itch. You can also set up some humidifiers for inside. We have very dry weather here also, it is bad on all of us so we started doing this and it helps us a lot so I imagine it makes the dogs feel better too.