Tobin D J, Fenton D A, Kendall M D
Unit of Cell Biology, Division of Biochemistry, UMDS, London, England.
J Cutan Pathol. 1990 Dec;17(6):348-54. doi: 10.1111/j.1600-0560.1990.tb00111.x.
The prime diagnostic feature of acute alopecia areata is the presence of exclamation mark hairs. These characteristic hairs fracture at their distal end and taper proximally towards the scalp, giving them the appearance of an exclamation mark. Hair morphology was studied in 8 patients with untreated acute alopecia areata and 3 normal adults without hair loss. Light microscopy, transmission and scanning electron microscopy revealed distinct structural differences in the distal end of hairs compared with the remainder of their length and with normal hair shafts. Transverse sections of hairs just below the frayed brush-like tip often displayed asymmetrical cortex disintegration. One side was compact and homogeneous while the other was deeply fissured and/or broken up into discrete heterogeneous-staining fragments of cortical, stratum corneum and cuticular components in addition to apparently degenerate cortex. Many exclamation mark hair tips lacked cuticle and had irregular profiles. Melanin was found in cortical and medullary fragments at the tip, although it was absent in the more degenerate forms of cortex. More proximal sections of these pathognomic telogen hairs revealed nearly normal hair shaft ultrastructure.
急性斑秃的主要诊断特征是惊叹号样毛发的存在。这些特征性毛发在其远端断裂，并向近端朝着头皮逐渐变细，使其呈现出惊叹号的外观。对8例未经治疗的急性斑秃患者和3名无脱发的正常成年人的毛发形态进行了研究。光学显微镜、透射电子显微镜和扫描电子显微镜显示，与毛发其余长度以及正常毛干相比，毛发远端存在明显的结构差异。在磨损的刷状尖端下方的毛发横切面通常显示出不对称的皮质崩解。一侧致密且均匀，而另一侧则有深深的裂缝和/或分解成离散的、染色不均一的皮质、角质层和表皮成分碎片，此外还有明显退化的皮质。许多惊叹号样毛发尖端缺乏角质层且轮廓不规则。在尖端的皮质和髓质碎片中发现了黑色素，尽管在更退化的皮质形式中不存在。这些典型休止期毛发的更近端部分显示出几乎正常的毛干超微结构。
