An inflammatory condition of the skin that most commonly occurs on the scalp, face, and chest. The term dandruff or pityriasis capitis corresponds to a milder form of seborrheic dermatitis that is thought to result from a combination of factors. Clinical features can range from fine scaling of the scalp to erythematous patches. It is a relapsing condition that may require maintenance treatment. Anti-dandruff shampoos are readily available and effective in most cases. Common active ingredients include selenium sulfide, zinc pyrithione, ketoconazole, miconazole, and ciclopirox .Tar-based shampoos are also effective.