Department of Dermatology, Huashan Hospital, Fudan University, Shanghai, China.
Unilever Shanghai Research Centre, Shanghai, China.
J Cosmet Dermatol. 2021 Sep;20(9):2950-2962. doi: 10.1111/jocd.13932. Epub 2021 Feb 13.
Postinflammatory hyperpigmentation (PIH) reflects a dynamic process from primary injury and cutaneous inflammation to subsequent melanogenesis and hyperpigmentation, of which pathogenesis remains unclear, hindering the development of targeted therapies.
To observe the dynamic development of PIH; determine the starting point and peak point of the inflammatory phase and pigmentary phase; and clarify the timing of anti-inflammatory and anti-pigmentary treatment.
Thirty healthy volunteers with Fitzpatrick skin types III-IV were enrolled and underwent suction blisters. The noninvasive evaluation of inflammation and hyperpigmentation on suction blister sites were performed via spectrophotometry (CM2600d and SIAscope) and RCM for the following 24 weeks.
We successfully observed suction blister-induced PIH lasting over 24 weeks. The inflammatory phase started soon after the procedure and lasted for 8-12 weeks, manifested by significantly elevated a* values and erythema index detected by spectrophotometry, as well as inflammatory infiltration and angiogenesis shown in RCM images. Meanwhile, melanogenesis was accelerated after week 3 and reached peak on week 8, manifested by significantly accumulated melanin granules and bright pigment rings in different depths under RCM, which was in parallel with elevated melanin index. The darkening skin tone in PIH actually presented a mixture of inflammatory erythema, angiogenesis, and hyperpigmentation. The inflammation and pigmentation phases of PIH were not sequential but partially overlap.
The duration of suction blister-induced PIH is more than 24 weeks. The inflammatory phase partially overlaps with the pigmentary phase, and those drugs with anti-inflammatory and anti-pigmentary dual effects are potential choices.
炎症后色素沉着（PIH）反映了从原发性损伤和皮肤炎症到随后的黑色素生成和色素沉着的动态过程，其发病机制尚不清楚，这阻碍了靶向治疗的发展。
观察 PIH 的动态发展；确定炎症期和色素期的起始点和峰值；阐明抗炎和抗色素治疗的时机。
纳入 30 名皮肤类型为 III-IV 的健康志愿者进行吸疱。通过分光光度计（CM2600d 和 SIAscope）和 RCM 对吸疱部位的炎症和色素沉着进行非侵入性评估，共 24 周。
我们成功观察到持续超过 24 周的吸疱诱导的 PIH。炎症期在操作后很快开始，持续 8-12 周，分光光度计检测到 a*值和红斑指数显著升高，RCM 图像显示炎症浸润和血管生成。同时，黑色素生成在第 3 周后加速，并在第 8 周达到峰值，RCM 下不同深度的黑色素颗粒明显堆积，色素环明亮，黑色素指数显著升高。PIH 的肤色变暗实际上是炎症性红斑、血管生成和色素沉着的混合物。PIH 的炎症期和色素期不是顺序发生的，而是部分重叠的。
吸疱诱导的 PIH 持续时间超过 24 周。炎症期与色素期部分重叠，具有抗炎和抗色素双重作用的药物是潜在的选择。
