Duong Amanda N, Kincaid Colin, Phong Celine, Babadjouni Arash, Mesinkovska Natasha Atanaskova
Department of Dermatology, University of California, Irvine, CA, USA.
Skin Appendage Disord. 2025 Apr;11(2):143-146. doi: 10.1159/000541222. Epub 2024 Oct 11.
Clinical examinations of the scalp have shown that patients may grow hair preferentially at higher density on one side of their scalp, yet review of the literature to date has not yield studies that directly assess differences in scalp hair density laterality. The objective of this study was to examine whether scalp hair growth occurs preferentially and on which side of the scalp, the right or left, in healthy patients.
Scalps of healthy subjects with no history of hair loss or scalp disease were imaged with digital trichoscopy at a university dermatology clinic. Bilateral temporal photos were uploaded to trichoscopy software for quantitative analysis.
Scalp hair laterality was observed in both male and female, with no trend in left or right preference. While subjects who identified as Asian or Hispanic exhibited a strong laterality preference, statistical significance was not reached among African American or Caucasian subjects.
No overall side preference was observed in the study population, yet many of the healthy individuals tend to preferentially grow more hair on one side of their scalp. It is possible that in addition to genetics, certain behavioral or environmental factors may play a role in laterality.
对头皮的临床检查表明，患者头皮一侧的头发生长密度可能更高，但迄今为止的文献综述尚未产生直接评估头皮毛发密度左右差异的研究。本研究的目的是检查健康患者的头皮毛发生长是否存在偏好，以及偏好发生在头皮的哪一侧，右侧还是左侧。
在大学皮肤科诊所，对无脱发或头皮疾病史的健康受试者的头皮进行数字毛发镜成像。双侧颞部照片被上传到毛发镜软件进行定量分析。
男性和女性均观察到头皮毛发的左右差异，无左右偏好趋势。虽然自认为是亚洲人或西班牙裔的受试者表现出强烈的左右差异偏好，但非裔美国人或白种人受试者未达到统计学意义。
在研究人群中未观察到总体的一侧偏好，但许多健康个体倾向于在头皮的一侧优先长出更多头发。除了遗传因素外，某些行为或环境因素可能在左右差异中起作用。
