The causes of acne are not fully understood, but dermatologists have certainly evolved in their knowledge and treatment approaches. During the process, many things that were believed to be associated with acne have either been ruled out, or modified with a deeper understanding.

Acne can occur at any time during a person's life. Whilst many people suffer acne during teenage years, not having acne then does not mean it may not develop as an adult. However, genetics does play a role. So if someone in your family has acne, there is a greater chance of developing it.

But acne is not contagious. During teenage years, for women who are menstruating, and women going through menopause, there are hormonal changes that are associated with acne.

Acne sufferers have oil producing glands that are more sensitive to regular levels of the hormone testosterone in their blood. Sometimes too much testosterone is produced. Women have small amounts of testosterone also, and for some women, adrenal or ovarian disease is an underlying cause of acne which causes excess production of these male hormones.

Testosterone, or the body's heightened responsiveness to it, causes the oil glands to produce more oil than they should. Here, other factors such as excess shedding of the dead skin cells lining the hair follicle, a narrowing of the hair follicles, and irregular clumping of the cells within the hair follicles, come into play. The end result is that the follicles become clogged with dead skin cells and oil, and the opening of the follicle is blocked. This is called a comedone.

This environment favors the multiplication of the acne bacteria, Propionibacterium acnes. This bacteria lives on the skin and is normally harmless. But the oil and dead cells in the clogged pore are like food to it, and the breakdown products of this bacteria's mealtime is irritating to the skin. If the bacteria multiply to the extent that the follicle wall breaks open, lesions can develop.

The role of inflammation in acne is being studied to give new insights into how to approach acne treatment. The inflammatory process within the skin can attract molecules that break down the collagen in the skin. This can lead to permanent damage - scarring. A research team at the University of Michigan is looking at testing treatments that reduce the intensity of the immune system's response to the effects of the 'acne invasion'. By reducing the level of inflammation, they hope to prevent acne scarring.

References:

1. innovations-report.com/html/reports/medicine_health/report-33149.html