Chemical reconstruction of skin scars (CROSS) method for atrophic scars: A comprehensive review

Background: Chemical reconstruction of skin scars (CROSS) applies a high strength acid focally to treat atrophic scars. Although this method has gained popularity over the past two decades, no standardized treatment guideline exists for CROSS method in the treatment of atrophic scars. Aims: The purpose of this comprehensive review is to evaluate the indications, detailed techniques, efficacy and safety of CROSS method. Materials and methods: An extensive literature review was conducted to identify articles relating to CROSS method for atrophic scars from 2002 to 2018. Results: The literature search yielded 19 articles meeting criteria. CROSS method has been used for the treatment of acne scars, varicella scars, enlarged pores and depressed surgical scars. In studies using the quantile grading scale for acne scars, 60-100% of patients showed >25% improvement. In two studies for varicella scars, 83-100% of patients showed >25% improvement. CROSS method seems to be effective specifically for ice-pick scars. It is well tolerated and safe in Fitzpatrick skin phototypes I-V. Most reported complications are temporary and include post-inflammatory dyspigmentation, erythema, pain, pruritus, infection and widening of scars. Conclusion: This literature review suggests that CROSS method is a safe and effective treatment for atrophic scars, especially ice-pick scars, in skin types I-V. However, current published works have several limitations, including small sample sizes, lack of control group, different concentrations of acid, different frequency of treatments and follow-up periods. Larger, randomized, controlled studies are needed to elucidate the optimal treatment protocol of CROSS method.