Atrophic Acne Scar and Histology

Jacob et al. divided atrophic acne scars into three types according to their size, depth, and three-dimensional structure [1] (Fig. 17.1). First, an icepick scar is a narrow, deep scar of less than 2 mm in diameter, just like an icepick. The opening in the surface is wider, taking the form of a funnel shaped V. Icepick scars are so deep that they are difficult to treat with laser resurfacing. Second, rolling scars are caused by dermal tethers that connect the dermis to the subcutaneous layer. They have an undulating form with shallow, rounded bases and take the form of an M. The diameter is 4–5 mm. Treatment is done by the removal of the dermal tether. Third, boxcar scars are wider than icepick scars. The base is wide and takes the form of a U, like a boxcar that is upside down. Boxcar scars can be divided into shallow boxcar scars, which can benefit from laser resurfacing, and deep boxcar scars, where the bottom is so deep that laser resurfacing is ineffective. However, all atrophic acne scars cannot be classified into these three types of scars, because they may have more than one characteristic. Thus, the classification of atrophic acne scars by Jacob et al. should be understood as a rough classification concept for approaching treatment.