INTRODUCTION
Evaluation of Acne ScarsAlthough several grading scales exist for acne scarring, there are many limitations in their application in daily clinical practice. Scars classifications is difficult even for acne experts, sometimes.To simplify, there are two basic types of acne scars depending on whether there is a loss or gain of skin volume: 80–90% of patients having scars associated with a loss of collagen (atrophic scars) compared to a minority of subjects showing hypertrophic scars and keloids (with a ratio atrophic/hypertrophic scars 3:1).Atrophic ScarsAtrophic scars can be sub-classified into ice-pick (60%–70% of total scars), boxcar (20%–30%), and rolling scars (15%–25%).1 In Table 1 we summarize morphological features and corresponding clinical aspect of different type of atrophic scars. Among classifications and scales proposed by several authors, the qualitative scarring grading system proposed by Goodman and Baron2 is simple and universally applicable (Table 2). The qualitative approach is useful in mild post acne scarring, but the main limitation of these scales is the subjectivity of the assessment. In the observation of severe cases, different patterns are simultaneously present and may be difficult to differentiate. For these cases, Goodman developed a quantitative global acne scarring assessment tool3 based on the type of scar and the number of scars. This system assigns fewer points to macular and mild atrophic scars, and highest score to moderate and severe atrophic scars (macular or mildly atrophic: 1 point; moderately atrophic: 2 points; punched out or linear-troughed severe scars: 3 points; hyperplastic papular scars: 4 points). The multiplication factor for these lesion types is based on the numerical range: for 1-10 scars, the multiplier is 1; for 11–20 scars, the multiplier is 2; for more than 20 scars, the multiplier is 3. Other systems have been proposed to improve the approach to the classification of acne scars. In 2017, the Global Alliance to Improve Outcomes in Acne presented a system based on the global grading scale.4 Tan et al proposed a six-category global severity scale (SCAR-S) for assessment of acne scarring at each of the face, chest, and back.5The ECCA (Echelle d’Evaluation clinique des Cicatrices d’acn´e)6 for facial acne scarring is also a quantitative scale, designed for use in clinical practice with the aim of standardizing discussion on scar treatment and is based on the sum of individual types of scars and their numerical extent. The potential advantages of this system include independent accounting of specific scar types, thereby providing for separate atrophic and hypertrophic sub-scores in addition to total scores. Potential shortcomings include restriction to facial involvement, time intensity, and undetermined clinical relevance of score ranges.Hypertrophic and Keloidal ScarsKeloids and hypertrophic scars are caused by cutaneous injury and inflammation. Notably, superficial injuries that do not reach the reticular dermis never cause keloidal and hypertrophic
