Abstract: 【Abstract】 Objective To investigate clinical features and non-invasive skin imaging findings of acquired facial hyperpigmented macules in children. Methods A retrospective analysis was conducted on the clinical characteristics of children with acquired facial hyperpigmented macules diagnosed in the Outpatient Department of Dermatology, Wuhan Hospital of Traditional Chinese and Western Medicine, Tongji Medical College, Huazhong University of Science and Technology from January 2020 to June 2023. Reflectance confocal microscopy and dermoscopy were performed to observe lesions and perilesional normal skin, and summarize the imaging findings. Results A total of 131 children with acquired facial hyperpigmented macules were collected, including 88 males and 43 females; their ages ranged from 2 to 25 months, the age at onset was 11.50 ± 7.15 months, and the disease duration was 6.50 ± 4.66 months. The lesions were distributed in the temporal and/or frontal regions, mostly measuring 4 to 10 mm in length, and they mainly manifested as non-confluent irregular brown or brownish-red hyperpigmented macules, without scales on the surface. The total number of lesions was less than 10 in 19 cases （14.50%）, between 10 and 20 in 75 cases （57.25%）, and more than 20 in 37 cases （28.24%）. Reflectance confocal microscopy revealed no elongation of the rete ridges, but mild increased pigmentation in the basal layer, slight vascular dilatation in the dermal papilla and superficial dermis, and scattered melanophages and inflammatory cell infiltration in some lesions. Dermoscopy showed pigment networks with varying color darkness, which were distributed along the dermatoglyphs, and mixed with linear or punctate vessels. Conclusions Acquired facial hyperpigmented macules is a common skin disease occurring in infants and young children, and is characterized by typical lesions by reflectance confocal microscopy and dermoscopy. Histopathological examination may be unnecessary for its diagnosis, and skin imaging techniques can help improve diagnostic accuracy.

Key words: Pigmentation disorders, Child, Dermoscopy, Microscopy, confocal, Facial dermatoses, Diagnosis, differential, Acquired macular hyperpigmentation