Ajay Agarwala, age 9, of Kendall Park, N.J. for his question:

WHAT IS DANDRUFF?

Flakes of dry skin from the scalp are called dandruff. Mixed with the flakes of skin is grease from the oil glands of the scalp.

A certain amount of scaling of the skin from the scalp is normal. Control can be established by setting a regular routine of properly washing, brushing and occasionally oiling the scalp and hair.

A condition called seborrheic dermatitis is actually a disease in which there is an excessive supply of sebum, the oily secretion from glands of the skin. The result is a greasy scaling of the skin's surface.

Dandruff can also be found on parts of the body other than the head, such as the chest or under the armpits.