Maxfield Luke, Cook Christopher
Sampson Regional Medical Center
Hair growth is cyclical, and follicles undergo corresponding phases of growth (anagen), involution (catagen), and quiescence (telogen). Loose anagen hair syndrome (LAS) is a condition inherited in autosomal dominant fashion with incomplete penetrance or as sporadic cases. It is characterized by non-scarring alopecia with increased hair shedding due to poorly anchored anagen hairs. The disease presents most commonly in female children with diffuse thinning and textural changes characterized as unruly. Hairs are easily and painlessly removed during daily activities and reproduced with a hair pull test. On light microscopy, a deformed anagen bulb, absent inner root sheath, and ruffled cuticle are present. Histopathologic exam, although not a part of routine diagnosis, reveals premature and defective keratinization of the inner root sheath. Most cases resolve spontaneously, but topical minoxidil may be used as first-line therapy in infants and children.
头发生长是周期性的，毛囊会经历相应的生长（生长期）、退化（退行期）和静止（休止期）阶段。松散生长期毛发综合征（LAS）是一种以常染色体显性方式遗传且具有不完全外显率的疾病，或为散发病例。其特征为非瘢痕性脱发，由于生长期毛发固定不牢导致脱发增加。该病最常见于女童，表现为弥漫性头发稀疏和质地改变，特征为难以梳理。在日常活动中，毛发很容易且无痛地脱落，毛发牵拉试验可再现这种情况。在光学显微镜下，可见生长期毛球变形、内根鞘缺失和角质层起皱。组织病理学检查虽然不是常规诊断的一部分，但显示内根鞘过早且有缺陷的角化。大多数病例可自行缓解，但局部用米诺地尔可作为婴幼儿的一线治疗方法。
