Flaking and itching can be controlled.

• Position: Dandruff control

Dandruff affects approximately 50,000,000 Americans. Last year, consumers spent more than $300,000,000 on products to control the condition. It isn't serious or life-threatening, but for those who suffer from this minor medical malady, it can be annoying and embarrassing.

Dandruff is characterized by excessive dry, flaky scales and an itchy scalp. Persistent dandruff may involve severe, clumpy flaking and sometimes a red, irritated scalp. "Everyone normally sheds tiny bits of dead skin cells," points out Richard S. Berger, clinical professor of dermatology, Robert Wood Johnson Medical School. "Unfortunately, some people are prone to scaling larger clumps of skin which lead to conspicuous flaking."

Although symptoms can appear in all age groups, dandruff most frequently occurs after puberty, between the teenage years and age 40. It also is common in the elderly. Dandruff is not partial to sex; there are as many men sufferers as women. Most find that their symptoms intensity in the winter.

The precise cause is the subject of debate among physicians. A leading theory is that dandruff is caused by the yeast-like fungus, Pityrosporum ovale, which occurs naturally on everyone's scalp. An overabundance...