Skin. It is the largest of the body. Skin is the body's first barrier to infection. It keeps out many harmful and other things. It also keeps all the things we need in our bodies.

The skin helps control body . Glands on the skin release fluid to cool the body when it gets too hot. When a person gets too cold, blood in the skin become narrow. This helps to trap heat inside the body.

Like other organs of the body, the skin can have problems. Almost any can tell you the most common disorder: acne. Acne is connected to hormones and how they affect the oil of the skin.

The skin gets its oil, called sebum, from the sebaceous glands. Each gland to a passage of extremely small hairs. The sebum travels through these passages. The oil reaches the surface of the skin through little holes, called . Sometimes, the sebum, hair and cells of the pores block these openings. This is how acne starts.

Bacteria can grow in a blocked pore. The produce chemicals and enzymes. White blood cells -- infection fighters -- travel to the area. All this leads to a growth on the skin, a . This becomes red, hot and often painful.

Some people think eating chocolate or oily foods causes . Others blame dirty skin or nervous tension. Yet researchers tell us none of these acne.

So what does? Doctors are not sure. But they have some ideas. For one thing, they know that called androgens are involved. Androgens cause the sebaceous glands to grow and make more .

Young people will not be happy about this next fact. increase when boys and girls enter their teenage years.

There are several for acne. Mild cases are generally treated with medicines for use directly on the skin. These often contain salicylic acid or benzoyl peroxide.

People with more serious acne may be given drugs to take by mouth. Or they might use a combination of other treatments.

One used to treat the most severe forms of acne is called isotretinoin. It is sold under different names, including Accutane.

Isotretinoin has been shown to acne in ninety percent of people who use it. The drug is normally taken for about months. However, it can cause serious problems in some cases. If used during , for example, isotretinoin can harm the developing . That is why health experts strongly advise pregnant women and those who may become pregnant against using the drug.

Skin experts say there are simple ways to help acne. One is to touch your face as little as possible, so as not to add oils or put on the skin.

Another good idea is to avoid the to burst pimples. This can leave permanent marks on the skin.

Doctors also say to strong cleaning products, and to be gentle as you wash and dry your skin.