Why is my scalp constantly itchy and flakes off?my hair is very oily but my scalp is very dry

Basics: Scalp skin is somewhat different in that it is not as free to shed dead cells as easily as other body surfaces (more oil/trapped by hair). Many shampoos are good at removing soil but do not contain the chemicals needed to remove oils & break down the binds between dead cells that need to shed. Using a dandruff shampoo for oily hair usually helps keep it under control.