Trichotillomania (hair-pulling disorder) has high female preponderance. It has been suggested that onset in early childhood represents a distinct developmental subtype that is characterized by higher prevalence of males compared to later onset cases. However, the empirical literature is scarce. We conducted a systematic review of case reports to examine the distribution of age at onset/presentation in males and females with trichotillomania or trichobezoar (a mass of hair in the gastrointestinal tract resulting from ingesting hair). We identified 1065 individuals with trichotillomania and 1248 with trichobezoar. In both samples, males, compared to females, had earlier age at presentation and greater proportion of cases in early childhood. These sex differences remained after potential confounding variables were accounted for. The results showed similar sex differences for age at onset, which was reported in 734 and 337 of the trichotillomania and trichobezoar cases, respectively. The findings may reflect neurodevelopmental underpinnings in early childhood trichotillomania.

拔毛癖（拔毛症）以女性居多。有人提出，儿童早期发病代表了一种独特的发育亚型，其特征是男性患病率高于晚期发病病例。然而，经验文献很少。我们对病例报告进行了系统评价，以检查患有拔毛癖或滴虫病（因摄入毛发而在胃肠道中形成大量毛发）的男性和女性发病/就诊时的年龄分布。我们确定了 1065 名拔毛癖患者和 1248 名拔毛虫患者。在这两个样本中，与女性相比，男性的发病年龄更早，儿童早期的病例比例更高。在考虑了潜在的混杂变量后，这些性别差异仍然存在。结果显示，发病年龄的性别差异相似，分别在 734 和 337 例拔毛癖和滴虫病病例中报告。这些发现可能反映了儿童早期拔毛癖的神经发育基础。