Supplementary Material for: A Silvery Hair Revolution: Case Report of Marie Antoinette syndrome in a child

Background: Sudden diffuse hair whitening (canities subita) is exceptionally rare in childhood and may mimic congenital pigment dilution syndromes. Case presentation: We describe a 17-month-old girl who developed abrupt hair depigmentation during hospitalization for septic shock. Clinical examination, trichoscopy, and light microscopy confirmed diffuse alopecia areata and achromotrichia. Hematologic and immunologic investigations were normal. Spontaneous repigmentation occurred within three months. Conclusion: This case—one of the youngest reported—highlights systemic stress as a potential trigger for pediatric canities subita associated with diffuse alopecia areata and underscores the importance of distinguishing it from congenital silvery hair syndromes, which carry markedly different prognostic and therapeutic implications.背景：突发性弥漫性毛发变白（canities subita）在儿童群体中极为罕见，临床表现易与先天性色素稀释综合征相混淆。 病例报告：本文报道1例17月龄女婴，因感染性休克住院期间突发毛发色素脱失。经临床检查、毛发镜（trichoscopy）及光学显微镜检查，确诊为弥漫性斑秃（diffuse alopecia areata）与毛发色素脱失（achromotrichia）。血液学与免疫学检查结果均正常，患儿于3个月内出现自发性色素恢复。 结论：本病例为目前报道的年龄最小的儿童突发性弥漫性毛发变白病例之一，提示全身性应激可能是伴发弥漫性斑秃的儿童突发性弥漫性毛发变白的潜在诱因，同时强调需将其与先天性银毛发综合征相鉴别——二者的预后与治疗策略均存在显著差异。