Is it dry and itchy all over or just a small section?
I have a section on the back of my scalp just above my neck but that's been diagnosed as dermatitis. It drives me crazy sometimes but I've been prescribed a lotion that calms it down. I also have to change shampoo regularly too. I can't use Pantene or many of the high street brands because it makes it even more irritable. I've been using a L'occitane one at the moment. What is ideal but doesn't smell great is using a coal tar based shampoo. I've used Capasal for years - it soothes the itchiness but you do smell abit like a coal yard. Your hair will feel amazing clean after it!
Hope that helps a little? x