Acne is a skin disorder that occurs mostly among teenagers. It consists of various kinds of blemishes, mainly on the face, upper chest, and back. A few blemishes are normal, but severe acne may result in permanent scarring. Some teenagers find severe acne so distressing that they develop emotional problems, which can be serious.

In most cases, acne appears during early adolescence-at about the age of 13, when a child starts to develop physically into an adult. This development is controlled by chemical substances called hormones. One kind of hormone stimulates the oil glands in the skin. These glands, called sebaceous glands, grow larger and produce more oil. Each sebaceous gland empties into a hair follicle, a bag like structure that surrounds a hair. Normally, the oil empties out of the follicle through a pore that opens onto the skin surface.

Sometimes the pores become clogged and oil accumulates inside them. A clogged pore forms a blemish called a blackhead or whitehead. The black colour of a blackhead comes from a normal skin pigment that darkens when exposed to air. A white head develops if a pore is so clogged that no air can enter.

Small, pus-filled bumps called pimples, or tender red lumps called cysts, may also develop. Pimples and cysts are caused by the acne bacillus, a germ that lives near the hairs below the skin surface. This germ breeds in the backed-up oil, producing an infection that causes redness and pus. Cysts may leave permanent scars, but pimples do not scar unless squeezed or pricked.

A poor diet, worry, and various bad habits are often blamed for acne, but they have little to do with the disorder. A balanced diet, enough sleep and exercise, and regular washing are good for the complexion and general health but cannot prevent or cure acne. Mild acne can be treated with nonprescription lotions that contain benzoyl peroxide or other medications. Heavy makeup make acne worse and should not be used.

 Severe acne should be treated by a doctor. Antibiotic may be prescribed which attacks the acne bacillus. Medications containing vitamin A acid may be applied to the skin to help prevent new blemishes.