Dandruff is the excessive flaking of skin from the scalp and is a normal bodily function. The size of the flakes and the speed with which they fall makes dandruff a problem for some people. Also, the drier the skin the faster it sheds. Dandruff tends to be worse during the winter.
There is no cure for dandruff, but it can be controlled with the use of non-prescription |shampoos| that slow down the turnover of the skin layer, break up the flakes into smaller particles, and reduce the itching. The active ingredients that provide these benefits are zinc pyrithione or selenium sulfide. Salicylic acid and sulfur are the active ingredients of other dandruff-fighting products. These work by breaking down particles of ~keratin~, a |protein| layer of the skin, and removing them from the scalp.
Psoriasis is a disease, characterized by pink or dull red patches or sores that are flat on top and covered by silvery scales, which usually appear on the scalp, knees, |fingernails|, trunk and anogenital areas. As with dandruff, there is no cure for psoriasis, but its severity can be decreased with the use of coal tar products which are applied topically to control itching and clean the skin; corticosteroids which help control itching and slow down the turnover rate of the skin cells; salicylic acid and sulfur-based products which speed the removal of damaged skin; and prescription medications taken orally to stop reproduction of skin cells and decrease scaling.
It is important to consult your physician or pharmacist before using any over-the-counter drugs or treatments. They will be able to advise you on proper usage and can warn you of possible side effects and contraindications.
