Acne is a common condition experienced by up to 85% of people between 11 and 30 years of age and by up to 5% of older adults. In some patients, during the healing process of active acne, the severe inflammatory response results in permanent, disfiguring scars.
Classification of Acne Scars
There are two basic types of acne scars depending on whether there is a net loss or gain of collagen. 80%-90% of people with acne scars have scars associated with a loss of collagen (atrophic scars) compared to a minority who show hypertrophic scars and keloids. It is unclear why some acne patients develop scars while others do not, as the degree of acne does not always correlate with the incidence or severity of scarring.
The atrophic acne scars can be further divided into 3 sub-categories (Figure):
Boxcar scars have sharp cliff-drop-like vertical margins and a larger, flatter base and usually appear on the temples and the cheeks. Their appearance is similar to chicken pox scars.
Rolling Scars are wide and shallow and create a wave-like appearance. They become visible when the tissue beneath the skin gets damaged. Their aspect resembles rolling hillsides.
Ice pick scars are deep and narrow and form pits in the skin. This condition is usually caused by a deep pimple or cyst that has destroyed the follicle.
Unlike the more common atrophic scars, here we see extra tissue where the scar is, in the form of a bump. Hypertrophic scars occupy the site of the original acne lesion, while keloid scars grow beyond the boundary of the original wound. Both are more commonly found on the chest and back, however they can occur on the face as well.