Division of Over the Counter Drug Options: Controlling Dandruff

by Food and Drug Administration (FDA)

If you're troubled by dandruff, that snowy, dust-like stuff that falls from scalp to shoulders, you're not alone: Nearly everyone has dandruff to some degree.

Dandruff is treatable with over-the-counter (OTC) products and causes no general health problems or permanent damage. But care must be taken not to confuse simple dandruff with other conditions that also cause flaking of the scalp, such as seborrheic dermatitis or psoriasis.

Dandruff occurs when the scalp sheds dead epidermal (skin) cells in large clumps. Dandruff scales appear dry, white or grayish, appearing as small, unsightly patches, especially on top of the head.

Scalp cells replenish themselves in a pattern similar to that of hair, but more rapidly: The skin of the head renews itself about once a month. Dead scalp cells are constantly being pushed from the deepest layer of the epidermis to the skin's surface, where they gradually die. Usually the scalp sheds them in a nearly invisible way. But for reasons that are still unclear, cell turnover sometimes becomes unusually rapid, and dead cells are shed as the visible flakes called dandruff.

In 1990, FDA banned 27 ingredients in dandruff shampoos because they were not proven safe and effective. Today dandruff can be treated with OTC drug products containing five ingredients FDA has verified as safe and effective: salicylic acid, pyrithione zinc, sulfur, selenium sulfide, and coal tar. FDA allows drug products to be sold without a prescription if they are safe for consumer use without a doctor's supervision and provide adequate detailed information for use on their labels.

Approved OTC ingredients for dandruff treatment are available in shampoos, rinses, or in products that users apply and leave on the scalp. Each works in different ways to control dandruff symptoms like scaling or itching.

OTC drug products are available in an estimated 750,000 outlets nationwide, including pharmacies and supermarkets, according to the Nonprescription Drug Manufacturers Association (NDMA). NDMA also reports that dandruff is among the top 10 problems consumers are most likely to treat with OTC drug products: 59 percent of the time dandruff sufferers use OTC drug products.

Coal-tar preparations and salicylic acid are approved for treating dandruff, seborrheic dermatitis, and psoriasis; pyrithione zinc and selenium sulfide for dandruff and seborrheic dermatitis; sulfur for dandruff; and salicylic acid and sulfur in combination for dandruff treatment. On Jan. 28, 1994, FDA published a final rule amending the monograph published in the Dec. 4, 1991, Federal Register allowing micronized selenium sulfide in a concentration of 0.6 percent to be included as an active ingredient to control dandruff.

According to Ida I. Yoder, a chemist in FDA's Office of OTC Drug Evaluation and a member of its drug policy staff, micronized selenium sulfide is a very finely ground form of selenium sulfide, with a particle size of approximately 5 micrometers. Because the selenium sulfide is more finely ground, it can be used at lower concentration levels.

"A drug is intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease, or intended to affect the structure or function of the body," says Yoder. Shampoos classified as cosmetics cannot make such medical claims. They are marketed for cleansing, beautifying, or promoting attractiveness.

If a product only claims to wash off dandruff flakes, it could be considered a cosmetic, Yoder says. But if it claims to prevent or treat the condition, it's considered a drug.

What Makes the Flake?

Although most people assume dandruff comes from a dry scalp, the opposite is true: People with oily scalps tend to suffer most from dandruff.

"This may be due to an oily scalp supporting the growth of yeast in the scalp, which is thought to be instrumental in the development of scaling and scalp irritation," says Joseph P. Bark, M.D., chairman of dermatology at St. Joseph's Hospital in Lexington, Ky. "A large preponderance of males have dandruff, which may suggest some role of androgen hormones in dandruff."

Children under 10 rarely have dandruff, but it is common in adolescents. While some experts say it tends to decrease in middle and old age, Bark disputes this.

"It really is a postpubescent disease, but I don't believe it diminishes in old age. We see a lot of dandruff and seborrheic dermatitis in stroke patients and in older people," he explains.

Bark says that dandruff has its bright side: If the scalp doesn't shed its dead skin cells, the human scalp would be tremendously thick.

"But when the cell turnover goes too far and increases, then you get not only visible excess scaling, but redness and itching," he says. "Redness and itching is actually seborrheic dermatitis, and it frequently occurs around the folds of the nose and the eyebrow areas, not just the scalp."

About the Author

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FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.