Clearasil Be Skin Smart. Get the real truth about zits. Skinexpert.net Overview of skin conditions, acne and outline of possible treatments from Boots Healthcare International. Oily skin and acne are caused by an increase in the production of sebum, the body's natural oil. This tends to occur during adolescence when hormone levels are changing rapidly.
Sebum comes from the sebaceous glands, which surround the hair follicles.
When there is an excess of sebum, the surface of the skin becomes very oily. This excess oil mixes with dead skin cells, which stick together to form a plug over the pores. This combination can turn into what scientists call a lesion. The content of the clogged pore can appear black as a result of dark pigment or oxidized oil, not because of dirt. Other non-inflamed lesions look like little white bumps on your skin.