Treatment options for a dry, itchy scalp due to seborrheic dermatitis or dandruff include topical cortisone, prescription antifungal shampoos, and over-the-counter shampoos that contain zinc pyrithione or selenium, according to Cleveland Clinic. Shampoos containing salicylic acid or coal tar are useful for treating itchiness due to psoriasis.
A dry, itchy scalp can also be the result of an allergic reaction to a substance such as hair dye, notes Cleveland Clinic. In most cases, an allergic reaction of this nature clears up once the person stops using the product. If necessary, a dermatologist can run tests to help a patient pinpoint the chemical responsible for the reaction.