Acne scars are classified as atrophic and hypertrophic. Atrophic scars are also classified as rolling, ice pick  and boxcar scars.

1. Ice-pick scars are narrow in diameter, deep, sharply marginated that extend vertically to the deep dermis or subcutaneous tissue.
2. Rolling scars are depressions of the skin with vertical extension limited to the depth corresponding to epidermal thickness.
3. Boxcar or U-shaped scars are uniform, round or oval scars with vertical edges and are usually wider at the surface.
4. Hypertrophic scars are typically pink, raised and firm.