Bergfeld W F
Department of Pathology, Cleveland Clinic Foundation, Ohio.
Adv Dermatol. 1989;4:301-20; discussion 321.
The major types of alopecia that can be diagnosed histologically are androgenic alopecia, alopecia areata, trichotillomania, inflammatory scarring alopecias, pseudopelade, and anagen and telogen effluviums. Important to recognize are the common histologic features in chronic alopecias, which include follicular plugging, decreased numbers of hair follicles, frequent increased fibrous tracts, and superficial changes of actinic damage. Specific helpful changes to be observed are (1) the presence of actinically damaged skin that would reveal a chronic alopecic condition, (2) the presence and site of the dermal inflammation, (3) whether there is a decrease in the numbers of hair follicles and the presence of a reversal of the anagen/telogen ratio, (4) miniaturization of the hair follicle, (5) evidence of involution, and (6) the presence of scarring as demonstrated with elastic fiber stains. By assessing these histologic changes, the dermatopathologist can make a reasonably specific diagnosis of alopecia.
可通过组织学诊断的主要脱发类型包括雄激素性脱发、斑秃、拔毛癖、炎症性瘢痕性脱发、假性斑秃以及生长期和休止期脱发。认识到慢性脱发常见的组织学特征很重要，这些特征包括毛囊堵塞、毛囊数量减少、纤维束频繁增多以及光化性损伤的浅表变化。需要观察的具体有用变化包括：（1）存在光化性损伤皮肤，这将揭示慢性脱发状况；（2）真皮炎症的存在及部位；（3）毛囊数量是否减少以及生长期/休止期比例是否逆转；（4）毛囊小型化；（5）退化证据；（6）弹性纤维染色显示的瘢痕形成。通过评估这些组织学变化，皮肤病理学家可以对脱发做出合理准确的诊断。
