Dandruff

Scaling of the Scalp
The most common type of scalp scaling is the condition popularly known as "dandruff". Almost everyone has experienced "dandruff" at some time-usually in the appearance of whitish to yellowish-white flakes on clothing and bedding as well as clinging to hair. "Dandruff" is regarded as unsightly and socially embarrassing. A great many proprietary shampoos, lotions and ointments are marketed as "anti-dandruff" treatments.

Although "dandruff" is the all-encompassing term for scales shed from the scalp, there are a number of different and distinct causes of scalp scaling. Some should receive medical diagnosis and treatment.

The normal loss of "dead cells" from the scalp is usually imperceptible or nearly so. The cells of the epidermis (outer skin layer) of the scalp are replaced about every 27 days; the "dead" cells scale off as they are replaced by new cells. Usually, not enough cells are shed at any one time to become noticeable.

Scalp scaling becomes noticeable, and an embarrassing problem, when something happens to (1) increase the rate of turnover in scalp epidermal cells, or (2) increase the size of shed flakes, as when increased scalp oiliness causes dead cells to adhere together into clumps.

The most common, and usually unprogressive, type of scalp scaling (pityriasis-shedding of bran-like flakes) is a slight increase in turnover on epidermal cells, with or without an increase in scalp oiliness (seborrhea). At various times there have been suggestions that this mild form of pityriasis is associated with micro-organisms on the scalp-specifically a yeast Pityrosporum ovale. This has never been definitively established. Mild pityriasis can usually be managed with regular shampoos about once a week. The use of anti-dandruff shampoos is more successful for some persons than for others. If the flake-shedding is successfully managed, there is no need to consult a physician.

Many of the other conditions that cause scalp scaling require medical diagnosis and treatment. Some of the causes are manifestations on the scalp of systemic diseases such as psoriasis or hormonal dysfunction. The size, form and color of the scalp scales can suggest a diagnosis. For example:

Abnormally heavy scaling, excessive scalp oiliness, open lesions on the scalp, and unrelieved scalp itching are all indications to consult a physician.

(For information about scalp disease from dermatologists, visit the website of the American Academy of Dermatology.