Dry skin and scalp is caused by scalp psoriasis, according to WebMD. Scalp psoriasis, a skin disorder, is characterized by dry skin and scaly patches that appear anywhere on the head, from the forehead to the neck and ears.
Although medical science has yet to identify the exact cause of this condition, WebMD explains that scalp psoriasis may be due to an immune system anomaly causing cells to grow at an unusually fast rate. These cells build up into thick patches and crusty lesions that lead to itching, infections and, in more severe cases, even hair loss. Notably, hair loss is caused not by the disorder itself but rather by frequent scratching and aggressive removal of scales, WebMD notes.
The first step in dealing with mild psoriasis is topical treatment, which include a range of shampoos, creams and ointments, such as salicylic acid and coal tar, according to WebMD. More serious cases of scalp psoriasis usually require a prescription for stronger medications, such as vitamin D derivative Anathralin and vitamin A derivative Tazarotene, as well as betamethasone, antimicrobials and steroid treatments. Once lesions from psoriasis clear up, frequent reapplication of treatments can help to keep the lesions from reappearing.