Cause and remedy of itchy scalp-no hair loss, scaling, lice, boils, discoloration,some relief using scalpicin?

infrequent, but once scratched the itching continues-location usually in two areas only-at the nape and right below the crown-no spredding-current duration 4 monthsCause and remedy of itchy scalp-no hair loss, scaling, lice, boils, discoloration,some relief using scalpicin?
have you changed hairspray shampoo ect or have you been stressed and over heated i use coal tar shampoo i find this helps