Why is my skin dry and itchy?

I have noticed my skin is alot drier than normal. And for the past 3 weeks my whole body has been itching. It seems like its getting gradually worse. If i scratch, i get these little bumps (they do not resemble bug bites) almost like an outbreak of hives. Then it goes away but comes back whenever i scratch. I haven't been using any new creams, lotions, or medications. I've noticed when hot water touches my skin when i shower or take a bath, the itching gets worse. I've used benadryl and cortizone cream. They work but only temporarily. I will probably be visiting a dermatologist soon if it doesn't stop. The only thing i can think of is stress related itch. Any ideas on what it could be or what to do about it?