Dandruff is the shedding of dead
skin cells from the
scalp. As skin cells die, a small amount of flaking is normal; about 487,000 cells/cm
2 get released normally after detergent treatment. Some people, however, experience an unusually large amount of flaking either
chronically or as a result of certain
triggers, up to 800,000 cells/cm
2, which can also be accompanied by redness and
irritation.