Clinical Features of Postnatal Pigmented Macular Lesions on the Pediatric Facial Region

Background Postnatal Pigmented Macular Lesions on the pediatric facial region, also known as Acquired facial hyperpigmented macules (AFHM), which manifest as non-segmental pigmentation without apparent localized inflammation history, usually occur on children's foreheads and temples. Hyperpigmented lesions in early childhood can be the presenting sign of serious diseases or benign conditions and often cause significant parental anxiety. This report summarizes its characteristics of a cohort of pediatric outpatients at our institution to provide research ideas for the possible pathogenesis and rational treatment of facial hyperpigmentation. Methods We performed a retrospective case series of pediatric patients who visited our outpatient department from December 2019 to June 2023 at our instution. General data regarding gender, age at Onset, season when Onset occurred, and course of disease were collected. Clinical signs, laboratory test results, and prognosis were also collected. Results The clinical features, including general data regarding sex, age at Onset, season of Onset, course of disease, clinical manifestation, laboratory test features, and prognosis, were analyzed and summarized. There were 17 boys and 15 girls enrolled in the study, including one pair of twins, with no sex-related susceptibility. The manifesting rash turned red after the patient cried or was exposed to the sun, leading us to believe that exposure is not the direct trigger for AFHM onset. However, constant sun exposure may cause persistent telangiectasia, leading to a delay in pigmentation resolution. Conclusion AFHM is a benign hyperpigmentation disorder, and the pigmentation of the skin will gradually subside with the enhancement of sun protection without special treatment. Strict sun protection might be an effective treatment for AFHM. As twins tend to show the same symptoms, genetic predisposition may play an essential role in the pathogenesis of AFHM. In future studies, we need to expand the sample size to further clarify the role of genetic susceptibility in the pathogenesis of AFHM.