Botulinum Toxin Type A is a potent neurotoxin that is produced by a gram‐positive bacteria clostridium botulinum. Its utilization in the treatment of various medical condition has expanded over the years in both medical and esthetic uses. It is being preferred by most physicians due to its efficacy and lack of side effects. It can be used as monotherapy or combined therapy. The aim of this review study was to show the role and mechanism of action of Botulinum toxin type A in the treatment and prevention of hypertrophic scars and keloids. The clear mechanisms underlying hypertrophic scars and keloids are still not clearly understood; however, the mechanism of action of Botulinum toxin type A has been shown to include action on wound tension, action on collagen, and action on fibroblasts. Different randomized controlled trials, double‐blind, and placebo‐controlled studies have been conducted to investigate its use in treatment and prevention of hypertrophic scars and keloids, and it still is one of the active areas of research in Dermatology and related fields. Method: In March 2018, we performed a literature search in PubMed for clinical studies, clinical trials, case reports, controlled trials, randomized controlled trials, and systemic reviews. The search terms we used were “BOTULINUM TOXIN” AND “HYPERTROPHIC SCARS” OR “KELOIDS” (from 1980). The search resulted in 1000 articles, out of these 35 articles met our inclusion exclusion criteria. Our inclusion criteria included relevant original articles relevant, critical systemic reviews, and crucial referenced articles, exclusion criteria included duplicates and articles not published in English language. We have reviewed these papers to show the role and mechanism of action of Botulinum toxin type A in the treatment and prevention of hypertrophic scars and keloids.

Objective This study was performed to analyze the efficacy, adverse reactions of fractional CO2 laser for atrophic acne scars, and related clinical factors. Methods: The clinical data of 121 patients with atrophic acne scars treated with ultra‐pulsed fractional CO2 laser in the Cosmetic Dermatology from August 2014 to March 2020 were retrospectively analyzed. The efficacy and adverse reactions of atrophic acne scar after fractional CO2 laser therapy were statistically analyzed. The clinical factors related to efficacy and adverse reactions after the first therapy session were analyzed by multivariate logistic regression. Results: A total of 121 patients received 206 sessions of fractional CO2 laser therapy, with an average of 1.7 sessions. Moderate to excellent improvement rate reached 50.4% after the first session. Multivariate logistic regression analysis indicated that rolling scars responded better to fractional CO2 laser treatment than icepick scars (OR = 7.3, 95% CI [1.2, 43.4], p = 0.029), and scar improvement was more significant in the high‐energy laser group than in the low‐energy laser group (OR = 10.9, 95% CI [1.1, 106.8], p = 0.041). The main adverse reactions after fractional laser surgery were pigmentation, skin sensitivity, persistent erythema, and acneiform eruption. Multivariate logistic analysis revealed that the longer the scar duration, the higher incidence of postoperative adverse reactions (OR = 1.3, 95% CI [1.1, 1.5], p = 0.008). Compared with icepick scars, rolling scars (OR = 10.4, 95% CI [2.3, 47.7], p = 0.003) and boxcar scars (OR = 12.0, 95% CI [3.3, 44.0], p < 0.001) had higher risk of developing adverse reactions. The incidence of postoperative adverse reactions was also higher in the combined mode group (DeepFX mode + ActiveFX mode) than in the single‐mode group (OR = 7.8, 95% CI [2.4, 25.5], p < 0.001). Conclusion: Fractional CO2 laser was effective in the treatment of atrophic acne scars, without serious adverse reactions. Scar type and laser energy were independent clinical factors affecting its efficacy. Scar course, scar type, and fractional laser mode were independent clinical factors affecting its adverse reactions.

Objective This study aimed to analyze the clinical results and influencing factors of the fractional microneedle radiofrequency (FMR) treatment for enlarged facial pores on different facial sites. Methods The clinical data of patients with enlarged facial pores who underwent FMR treatment from January 2019 to December 2020 were collected. The efficacy and complications of FMR for enlarged pores in different facial areas were retrospectively analyzed. Univariate and multivariate logistic regression analyses were used to explore the clinical factors related to the efficacy of FMR after the first treatment session. Results Totally, 75 patients with enlarged facial pores were included (full‐face FMR for 45, nasal FMR for 58, frontal FMR for 45, and cheek FMR for 72 patients). All patients received more than one treatment session, two patients received five treatment sessions, and the mean number of FMR session was 1.7. The moderate to excellent improvement rates in patients with nasal, frontal and cheek enlarged pores after the first session were 13.8%, 8.9%, and 11.1%, respectively. The improvement rate rose with the increasing number of treatment sessions. Multivariate logistic regression analysis revealed that long pulse‐width (300 ms) was positively associated with clinical efficacy after the first session (OR = 22.4, 95% CI [2.0–250.4], p = 0.012), compared with the short pulse‐width group (100–200 ms). The main adverse effects after FMR were transient pain, erythema, and edema. A minority of patients developed acneiform eruption. Conclusion This study confirms that FMR is safe and effective in improving enlarged facial pores. The pulse width is associated with the improvement of nasal enlarged pores.