Dandruff is itching and flaking of the scalp that some people start getting around puberty. The skin of the scalp has many layers. Cells start growing in the dermis at the bottom, and work their way up until they form a layer of dead cells on the skin surface. These dead cells fall off in small flakes which we don't even notice. Washing your hair or brushing it gets rid of these tiny flakes. Dandruff is caused by abnormalities in the division. And peeling of the epidermal cells of the scalp, which may be due to several reasons, such as fungal infections like ringworm of the scalp. The psoriasis Allergies to chemicals that touch on the scalp, and so on.