Abstract：
BACKGROUND: Laser hair removal (LHR) is one of the most requested cosmetic procedures worldwide. A rare side effect is the appearance of excess hair around previously treated areas, known as paradoxical hypertrichosis.
OBJECTIVE: The aim of this study was to retrospectively identify the cause of this side effect.
METHODS: This study included all patients who underwent LHR at our center between November 2018 and November 2020. Alexandrite laser hair removal (HR) or diode laser super hair removal (SHR) was performed in 70% and 30% of cases, respectively. Clinical features and daily habits of patients with and without postlaser hypertrichosis were compared.
RESULTS: Of the 7381 patients who received LHR, 25 patients (0.34%) demonstrated an increase in hair growth compared to baseline. Of these 25 patients, 24 had been treated with alexandrite laser HR (P < .01). The most common site was the upper arm, followed by the periareolar area. Daily sun protection was associated with a significantly lower incidence of hypertrichosis (P < .05), as was confirmed and shown to be independent of Fitzpatrick skin type by binary logistic regression analysis (odds ratio = 0.41, P < .05).
CONCLUSIONS: In our clinic, we observed paradoxical hypertrichosis after laser hair removal in a small minority of cases, as described by others. We did not observe differences in incidence related to skin type, but daily sun protection and LHR with diode laser SHR were associated with significant reductions in incidence rates. In addition to previously reported common sites, we also identified the periareolar area as a high-risk region.
OBJECTIVE: The aim of this study was to retrospectively identify the cause of this side effect.
METHODS: This study included all patients who underwent LHR at our center between November 2018 and November 2020. Alexandrite laser hair removal (HR) or diode laser super hair removal (SHR) was performed in 70% and 30% of cases, respectively. Clinical features and daily habits of patients with and without postlaser hypertrichosis were compared.
RESULTS: Of the 7381 patients who received LHR, 25 patients (0.34%) demonstrated an increase in hair growth compared to baseline. Of these 25 patients, 24 had been treated with alexandrite laser HR (P < .01). The most common site was the upper arm, followed by the periareolar area. Daily sun protection was associated with a significantly lower incidence of hypertrichosis (P < .05), as was confirmed and shown to be independent of Fitzpatrick skin type by binary logistic regression analysis (odds ratio = 0.41, P < .05).
CONCLUSIONS: In our clinic, we observed paradoxical hypertrichosis after laser hair removal in a small minority of cases, as described by others. We did not observe differences in incidence related to skin type, but daily sun protection and LHR with diode laser SHR were associated with significant reductions in incidence rates. In addition to previously reported common sites, we also identified the periareolar area as a high-risk region.
摘要：
背景：激光脱毛（LHR）是全球最需要的美容程序之一。一个罕见的副作用是以前治疗过的区域周围出现多余的头发，被称为矛盾的多毛症。
目的：本研究的目的是回顾性地确定这种副作用的原因。
方法：本研究包括2018年11月至2020年11月在我们中心接受LHR的所有患者。在70％和30％的病例中使用了Alexandrite激光（脱毛[HR]）或二极管激光（超级脱毛[SHR]），分别。比较有无激光后多毛症患者的临床特征和日常习惯。
结果：在7381名接受LHR的患者中，25名患者(0.34%)显示与基线相比毛发生长增加。在这25名患者中，用翠绿宝石激光（HR）治疗了24例（P<0.01）。最常见的部位是上臂，其次是乳晕周围区域。每日防晒与多毛症发生率显著降低相关(P<0.05),通过二元逻辑回归分析证实并显示与Fitzpatrick皮肤类型无关(OR=0.41,P<0.05).
结论：在我们的诊所，正如其他人所描述的，我们在少数病例中观察到激光脱毛后矛盾的多毛症。我们没有观察到与皮肤类型相关的发病率差异，但每日防晒和二极管激光(SHR)LHR与发病率显著降低相关.除了以前报道的常见网站，我们还将乳晕周围区域确定为高危区域.
目的：本研究的目的是回顾性地确定这种副作用的原因。
方法：本研究包括2018年11月至2020年11月在我们中心接受LHR的所有患者。在70％和30％的病例中使用了Alexandrite激光（脱毛[HR]）或二极管激光（超级脱毛[SHR]），分别。比较有无激光后多毛症患者的临床特征和日常习惯。
结果：在7381名接受LHR的患者中，25名患者(0.34%)显示与基线相比毛发生长增加。在这25名患者中，用翠绿宝石激光（HR）治疗了24例（P<0.01）。最常见的部位是上臂，其次是乳晕周围区域。每日防晒与多毛症发生率显著降低相关(P<0.05),通过二元逻辑回归分析证实并显示与Fitzpatrick皮肤类型无关(OR=0.41,P<0.05).
结论：在我们的诊所，正如其他人所描述的，我们在少数病例中观察到激光脱毛后矛盾的多毛症。我们没有观察到与皮肤类型相关的发病率差异，但每日防晒和二极管激光(SHR)LHR与发病率显著降低相关.除了以前报道的常见网站，我们还将乳晕周围区域确定为高危区域.
