I have a fat big boned 10 year old pug who has become flaky and itchy recently. He seems yo have very dry skin that flakes off when scratched/brushed. I've tried changing his food to a hypoallergenic one. I've tried different shampoos etc, I've given him more oily based food (don't trust your dog groomer and give coconut oil....the diarrhoea was horrific) such as sardines and even coated his skin in an oil treatment. He has Benadryl before bed if necessary.
He is still flaky and itchy. If MN is stumped then it's vet time. So sny ideas?