Abstract：
Keratosis follicularis spinulosa decalvans (KFSD) is a rare X-linked hereditary disorder characterized by the triad of follicular hyperkeratosis-photophobia-alopecia. The clinical heterogeneity makes the diagnosis difficult. To investigate the clinicopathologic and trichoscopic features of KFSD and to further clarify the essential requisites for the diagnosis, we conducted a retrospective study of patients with KFSD. The clinical information, histologic features, and trichoscopic findings were evaluated. Eight patients were from seven separate families. Two females were mother and daughter from the same family and the other six patients were male and represented sporadic cases. The average age of onset of alopecia was 21.25 years. Involvement of the scalp hairs leading to progressive scarring alopecia on the midline of the scalp with variable degrees of inflammation was the pathognomonic feature. It typically began after puberty. Vellus hair-associated follicular hyperkeratosis affected all of the patients. However, photophobia was not a constant feature. Histopathologic examination revealed disorders of the hair follicle with an acute-chronic inflammatory response. Follicular changes including fused infundibulum, the protrusion of the outer root sheath into the follicular canal, and a dilatation of the follicles at the isthmus level caused by the occlusion of keratin were observed. The trichoscopic features included perifollicular scaling, tufted hairs, and loss of follicular openings. In conclusion, terminal hair involvement, either scalp hairs, eyebrows, or eyelashes, and the hyperkeratosis of the follicle of vellus hairs is the diagnostic basis of KFSD. We hypothesize that follicular changes in histopathology are the primary event that trigger variable inflammation and further follicular destruction.
摘要：
毛囊角化病（KFSD）是一种罕见的X连锁遗传性疾病，其特征是滤泡性角化过度-畏光-脱发三联症。临床异质性使诊断困难。探讨KFSD的临床病理特征和镜下特征，进一步明确诊断的必要条件。我们对KFSD患者进行了回顾性研究.临床信息，组织学特征，和三镜检查结果进行了评估。八名患者来自七个不同的家庭。两名女性是来自同一家庭的母亲和女儿，其他六名患者是男性，代表散发病例。脱发的平均发病年龄为21.25岁。头皮毛发的参与导致头皮中线进行性瘢痕性脱发并伴有不同程度的炎症是病理特征。它通常在青春期后开始。与毛发相关的毛囊角化过度病变影响了所有患者。然而,畏光不是一个恒定的特征。组织病理学检查显示毛囊疾病伴有急慢性炎症反应。卵泡变化，包括融合漏斗，外根鞘伸入卵泡管,观察到由角蛋白闭塞引起的峡部毛囊扩张。三镜特征包括毛囊周围鳞屑，簇绒的毛发，和卵泡开口的丧失。总之,末梢毛发受累，无论是头皮毛发,眉毛,或者睫毛,绒毛毛囊角化过度是KFSD的诊断依据。我们假设组织病理学的卵泡变化是引发可变炎症和进一步卵泡破坏的主要事件。
