Dandruff is a common and often chronic (ongoing) scalp condition that is characterized by excessive shedding of dead skin cells from the scalp (skin that covers the top portion of the head). Dandruff flakes appear dry, white or grayish in color and emerge as small patches on top of the head.

Dandruff results from an overproduction of skin cells. It appears to be associated with an overgrowth of a common skin yeast called Malassezia. However, the relationship between the yeast and the skin flaking is not well understood.

Dandruff usually begins during puberty and is common throughout adolescence and young adulthood. People with oily skin and hair are more prone to dandruff.

Dandruff can typically be self-diagnosed and does not normally require medical treatment. However, if symptoms are severe and flakes are accompanied by redness and inflammation of the scalp or a secondary skin infection, it may indicate the presence of a related condition such as seborrheic dermatitis. In such cases, a patient should seek the care of a physician, usually a dermatologist.

The main therapy for dandruff is diligent and consistent shampooing of the scalp and head. Over-the-counter dandruff shampoos containing ingredients such as coal tar, salicylic acid and zinc pyrithione (an antifungal agent) may be recommended for more stubborn cases.