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.

Hypertrophic/keloid scars
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.

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Treatment of Acne Scars

It is essential for the clinician to choose a modality that can effectively reach the appropriate depth  of both superficial and deep scars. Acne scar treatments include surgical solutions such as punch  excision, subcision, chemical reconstruction, laser resurfacing or combinations of modalities. Non-  surgical options such as dermal fillers, chemical peels and dermabrasion are also available. Ablative  procedures are associated with long recovery times and adverse effects such as post-inflammatory  hyperpigmentation, especially in darker skin types, while non-ablative and fractional laser devices  have fewer side effects but multiple treatments are required to achieve acceptable outcomes