Acne

Acne is an inflammatory disease of the skin, caused by changes in the pilosebaseous units (skin structures consisting of a hair follicle and its associated sebaceous gland). 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 (acne). The face, chest, back and upper arms are especially affected by acne.

The typical lesions of acne are: small whitish or skin-colored bumps (whiteheads) or blackish elevations (blackheads). More inflamed rashes take the form of pus-filled, or reddish bumps, even boil-like tender swellings. After resolution of the lesions, prominent unsightly acne scars may remain.

The acne condition is common in puberty as a result of an abnormal response to normal levels of the male hormone testosterone. The response for most people diminishes over time and acne thus tends to disappear, or at least decrease, after one reaches the third decade of life. There is, however, no way to predict how long it will take for it to disappear entirely, and some individuals will continue to suffer from acne decades later, into their thirties and forties and even beyond.

Acne affects a large percentage of humans at some stage in life. Aside from scarring its main effects are psychological, such as reduced self-esteem and depression. Acne usually appears during adolescence, when people already tend to be at their most socially-insecure. For this reason acne should be treated if severe.

   Causes for acne

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 be linked to acne:
Stress
Hormonal activity
Hyperactive sebaceous glands
Accumulation of dead skin cells
Bacteria in the pores
Skin irritation or scratching of any sort
Anabolic steroids
Birth control pills, however many women have reported reduced acne while on the pill
Exposure to high levels of chlorine compounds, particularly chlorinated dioxins, can cause severe, long-lasting acne, known as Chloracne

Traditionally, attention has focused mostly on over-production of sebum as the main contributing factor of acne. More recently, more attention has been given to narrowing of the follicle channel as a second main contributing factor. Abnormal shedding of the cells lining the follicle, abnormal cell binding ("hyperkeratinization") within the follicle, and water retention in the skin (swelling the skin and so pressing the follicles shut) have all been put forward as mechanisms involved, but there does not appear to be much conclusive medical research on the subject.