Causes of Acne Scars

In the simplest terms, scars form at the site of an injury to tissue. They are the visible reminders of injury and tissue repair. In the case of acne, the injury is caused by the body’s inflammatory response to sebum, bacteria and dead cells in the plugged sebaceous follicle. There are two types of true scars: (1) depressed areas such as ice-pick scars, and (2) raised thickened tissue such as keloids.

When tissue suffers an injury, the body rushes its repair kit to the injury site. Among the elements of the repair kit are white blood cells and an array of inflammatory molecules that have the task of repairing tissue and fighting infection. However, when their job is done they may leave a somewhat messy repair site in the form of fibrous scar tissue, or eroded tissue.

White blood cells and inflammatory molecules may remain at the site of an active acne lesion for days or even weeks. In people who are susceptible to scarring, the result may be an acne scar. The occurrence and incidence of scarring is still not well understood, however. There is considerable variation in scarring between one person and another, indicating that some people are more prone to scarring than others. Scarring frequently results from severe inflammatory nodulocystic acne that occurs deep in the skin. But, scarring also may arise from more superficial inflamed lesions.

The life history of scars also is not well understood. Some people bear their acne scars for a lifetime with little change in the scars, but in other people the skin undergoes some degree of remodeling and acne scars diminish in size.

Whether acne scarring is deep or superficial, extensive or scattered, the esthetic result can be less than desirable and even disturbing. Acne scars can give the skin an "old" look. Scars may also contribute to an appearance of age as the skin loses its elasticity over the years.