The surprisingly similar histochemical changes in response to PUVA in acral and non-acral lesions did not manifest with clinical repigmentation except in non-acral ones. Factors such as inherent lower melanocyte density, lower melanocyte stem cell reservoirs and/or lower baseline epidermal stem cell factor may be considered as possible play makers in this respect.

Background Melasma continues to be a disease that is difficult to treat with no fully satisfactory results. The role of a fractional CO2 laser in its treatment is controversial. The addition of tranexamic acid (TXA) might be helpful. Objectives To assess the efficacy of a low‐power fractional CO2 laser alone versus its combination with tranexamic acid used either topically or intradermally for melasma treatment. Methods A randomized comparative split‐face study included a total of thirty female patients with bilateral, symmetrical melasma. The whole face was subjected to treatment via a low‐power (12 Watts) fractional ablative CO2 laser. One side was randomly assigned to topical application of tranexamic acid solution after the session immediately or intradermal microinjection of tranexamic acid prior to the laser session. Sessions were conducted every 4–6 weeks for five consecutive sessions. Assessments were done using the melasma area severity index MASI score, melanin index (MI), and erythema index (EI) before sessions and 2 weeks after the final session. Results After treatment, there was significant reduction in the MASI score on both sides of the face; the side treated with the fractional CO2 laser alone and the side treated with fractional CO2 laser combined with TXA (topically or intradermal injection) (P‐values 0.007, <0.001, and 0.016, respectively). MI was significantly lower on the side receiving fractional CO2 laser alone and the side receiving fractional CO2 laser combined with intradermal injection of TXA (P‐values <0.001 and 0.003, respectively), while the EI showed significant improvement only on the side receiving fractional CO2 laser alone (P‐value = 0.023). Although patients reported no differences in improvement on either treated side, the degree of improvement regarding the MASI score was better on the side receiving fractional CO2 laser alone. Regarding MI, the degree of improvement was higher on the side receiving fractional CO2 laser combined with intradermal injection of TXA than on the side receiving fractional CO2 laser alone; however, this improvement did not reach statistical significance. Minimal complications occurred in the form of mild pain. Conclusion A low‐power fractional CO2 laser is an effective, safe treatment for melasma. However, the addition of tranexamic acid (either topically or intradermally) to a fractional CO2 laser should be further studied. Lasers Surg. Med. 51:27–33, 2019. © 2018 Wiley Periodicals, Inc.

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Morphea is a rare fibrosing skin disorder that occurs as a result of abnormal homogenized collagen synthesis. Fractional ablative laser resurfacing has been used effectively in scar treatment via abnormal collagen degradation and induction of healthy collagen synthesis. Therefore, fractional ablative laser can provide an effective modality in treatment of morphea. The study aimed at evaluating the efficacy of fractional carbon dioxide laser as a new modality for the treatment of localized scleroderma and to compare its results with the well-established method of UVA-1 phototherapy. Seventeen patients with plaque and linear morphea were included in this parallel intra-individual comparative randomized controlled clinical trial. Each with two comparable morphea lesions that were randomly assigned to either 30 sessions of low-dose (30 J/cm) UVA-1 phototherapy (340-400 nm) or 3 sessions of fractional CO laser (10,600 nm-power 25 W). The response to therapy was then evaluated clinically and histopathologically via validated scoring systems. Immunohistochemical analysis of TGF-ß1 and MMP1 was done. Patient satisfaction was also assessed. Wilcoxon signed rank test for paired (matched) samples and Spearman rank correlation equation were used as indicated. Comparing the two groups, there was an obvious improvement with fractional CO laser that was superior to that of low-dose UVA-1 phototherapy. Statistically, there was a significant difference in the clinical scores (p = 0.001), collagen homogenization scores (p = 0.012), and patient satisfaction scores (p = 0.001). In conclusion, fractional carbon dioxide laser is a promising treatment modality for cases of localized morphea, with proved efficacy of this treatment on clinical and histopathological levels.

Ablative fractional CO2 laser is an effective and safe therapeutic option for XP with significantly shorter downtime and higher patient satisfaction compared with SP CO2 laser.