Abstract:

Wang Ying, Guan Zhiwei, Lin Yangyang, Chen Lixin, Hao Liangchen, Su Haihui, Lian Jia, Gong Zekun, Feng Xiaoyan, Wang Ji, Li Qinfeng. Department of Dermatology, Tianjin Children′s Hospital, Tianjin 300134, China Corresponding author: Li Qinfeng, Email: lyz20061217@sina.com 【Abstract】 Objective To investigate the microscopic features of common hypopigmentation disorders using confocal laser scanning microscopy （CLSM）. Methods Totally, 1915 child patients with hypopigmentation disorders were enrolled in this study, including 181 cases of vitiligo, 38 idiopathic guttate hypomelanosis, 370 amelanotic nevus, 304 lichen striatus, 712 pityriasis alba, and 310 postinflammatory hypopigmentation. CLSM was performed to observe all layers of depigmented lesions, their borders, and normal-appearing perilesional skin in these patients. Statistical analysis was done by chi-square test and Fisher′s exact test. Results Grade 1 and 2 hypopigmentation was observed in 984 （51.4%） and 684 （35.7%） out of the 1915 patients, respectively. The proportion of patients with grade 3 hypopigmentation was 77.9% （141/181） in patients with vitiligo, significantly higher than that in those with the other diseases （0 - 10.3%）. Among the 1915 patients, 815 showed mild epidermal hyperkeratosis, 1060 focal edema of stratum spinosum, 79 changes in dermal papillary rings, and 1133 sparse inflammatory cells or dendritic cells in the superficial dermis. There were significant differences in the degree of hypopigmentation and frequencies of pathologic changes in different skin layers on CLSM images among the six hypopigmentation disorders （all P < 0.05）. As CLSM showed, idiopathic guttate hypomelanosis was characterized by complete absence of dermal papillary rings; lichen striatus, pityriasis alba and postinflammatory hypopigmentation were all characterized by nonspecific inflammatory changes; lichen striatus manifested as punctiform or focal liquifaction degeneration of basal cells, and amelanotic nevus as only hypopigmentation and refractive attenuation; vitiligo was characterized by complete depigmentation and lack of integrity of dermal papillary rings in white patches. Conclusions CLSM images obviously differ between vitiligo, idiopathic guttate hypomelanosis, amelanotic nevus, lichen striatus, pityriasis alba and postinflammatory hypopigmentation, and can serve as a basis for their differential diagnosis.