Acne is a pustular infection of the skin, caused by changes in the sebaceous glands. The most common form of acne is known as acne vulgaris, which means common acne. Excessive secretion of oils from the glands combine with naturally occurring dead skin cells to block the hair follicles. Oil secretions build up beneath the blocked pore, providing a perfect environment for the skin bacteria Propionibacterium acnes to multiply uncontrolled. In response, the skin inflames, producing the visible lesion. The face, chest, back and upper arms are especially exposed.
Exactly why some people get acne and some do not is not fully known. It is known to be partly hereditary. Several factors are known to cause acne. Since the medical knowledge about acne is still relatively small, many misconceptions and rumours about what causes acne exists.
There is a myriad of products sold for the treatment of acne, many of them without any scientifically proven effects. However, a combination of treatments can usually prevent acne in all but the most severe cases.