Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: TUESDAY, October 12, 1993 TAG: 9310120107
SECTION: EXTRA PAGE: 6 EDITION: METRO
SOURCE: Jane Brody
DATELINE: LENGTH: Medium
An estimated 50 million people are plagued by whitish scales that descend upon their shoulders like confetti on a parade, a problem that not only gets worse with the passing of summer but also becomes more obvious when people don the darker colors of winter.
Although dandruff is very widespread and affects a part of the body easily accessible to doctors, exactly what goes wrong is still a hotly argued subject.
Only recently have dermatologists begun to better understand the likely cause or causes, and to begin to develop more effective treatments to curb it.
Contrary to what some people think, dandruff is not caused by poor hygiene, although infrequent shampooing may make it worse. And except for people with extremely dry skin everywhere on their bodies, dandruff is usually not the result of dryness. In fact, treatments intended to add oil to the scalp can make a dandruff problem much worse.
While most people with dandruff never consult a dermatologist or any other doctor about the condition, what many find the most effective remedy is available only by prescription. And some people with severe cases of dandruff actually have some other skin disease, like psoriasis, that is best treated by a doctor.
Like skin elsewhere on the body, the skin on the scalp constantly renews itself, and the old skin cells flake off, usually unnoticed. In dandruff, the replacement process is speeded up.
Whereas it would normally take 28 days for new skin cells to work their way to the scalp surface, in dandruff sufferers the process takes only about five days. In addition, the cells that slough off as dandruff are large and irregular and far more obvious than normal cells.
Most dandruff, as dermatologists now understand it, is a mild form of a skin condition called seborrheic dermatitis, an inflammation of the scalp and sometimes of the skin elsewhere on the body. It occurs in areas that have the greatest number of sebaceous, or oil, glands. In addition to the scalp, these include the skin of the eyebrows, eyelids, sides of the nose, behind the ears and in the middle of the chest.
Seborrheic dermatitis is associated with an overgrowth of a yeast-like fungus called Pityrosporum ovale that is a common inhabitant of the scalp. Treatments that suppress the growth of this organism and relieve symptoms of seborrheic dermatitis also bring ordinary dandruff problems under control, according to Dr. Richard Berger, dermatologist affiliated with the Robert Wood Johnson Medical School in New Brunswick, N.J.
This observation has prompted growing numbers of dermatologists to conclude that most dandruff is simply a mild form of the more severe dermatitis.
Sometimes, however, allergic reactions - for example, to a hair product like hair spray or dye - cause scalp inflammations that result in scales, redness and flaking of cells, notes Dr. Maria Hordinsky, a dermatologist at the University of Minnesota School of Medicine. Cradle cap in infants is a form of seborrheic dermatitis related to hormones from the mother.
In children, the fungal infection ringworm also can result in a flaky scalp. Children and sometimes adults with dandruff may also be suffering from an inherited allergic condition called atopic eczema, which can cause scaling of the scalp as well as other skin areas.
In others, immunological factors, like infection with the virus that causes AIDS, play a role. Psoriasis, a chronic skin condition that often involves the scalp, is another common cause of severe dandruff, resulting in inflamed skin with scales that are dry and silvery.
Regardless of the cause, most cases of dandruff improve during the summer and worsen during winter, an observation dermatologists cannot explain. Also, in any season, undue stress can worsen the condition.
The most commonly used treatments, non-prescription shampoos that contain selenium sulfide or zinc pyrithione or tars, suppress the growth of the Pityrosporum organism. Tar-containing shampoos are often recommended for dandruff problems caused by psoriasis.
A new product, Nizoral Shampoo, made by Janssen Pharmaceutica, requires a doctor's prescription but appears to be the most effective and longest lasting against seborrheic dermatitis as well as less severe forms of dandruff, according to clinical studies by Berger and other dermatologists. It contains the drug ketoconazole, a potent anti-fungal agent.
Berger said a controlled clinical trial showed that 80 percent of his patients benefited from this product, when used twice a week for four weeks and then only when needed to keep dandruff under control.
Hordinsky said that while many people were helped by a single product, others got the best relief by rotating anti-dandruff shampoos, using both over-the-counter and prescription products. New York Times
by CNB