University of Ottawa, Ottawa, Ontario, Canada.
Division of Dermatology, Ottawa Hospital, Ottawa, Ontario, Canada.
J Am Acad Dermatol. 2017 Mar;76(3):472-477. doi: 10.1016/j.jaad.2016.10.002. Epub 2016 Dec 20.
The hair pull test lacks validation and has unclear pretest guidelines.
We sought to quantify normal hair pull test values and elucidate the effect of pretest hair washing and brushing. The impact of hair texture and lifestyle was also examined.
Participants (n = 181) completed a questionnaire recording demographics, medications, and hair health/history. A single hair pull test (scalp vertex) was performed.
The mean number of hairs removed per pull was 0.44 (SD 0.75). There was no significant difference in the mean number of hairs removed regardless of when participants washed (P = .20) or brushed (P = .25) their hair. Hair pull test values were similar between Caucasian-, Asian-, and Afro-textured hair. There was no significant difference in hair pull values between participants taking medications affecting hair loss and participants not taking these medications (P = .33). Tight hairstyles did not influence hair pull test values.
Participant hair washing and brushing could not be controlled during the study, but this information was documented and analyzed.
Normal values for the hair pull test should be reduced to 2 hairs or fewer (97.2% of participants). The current 5-day restriction on pretest hair washing can be reduced and brushing be made permissible.
拔发试验缺乏验证，且试验前指导方针不明确。
我们旨在量化正常的拔发试验值，并阐明洗发和梳头对试验的影响。同时，我们还研究了头发质地和生活方式的影响。
参与者（n=181）完成了一份记录人口统计学信息、用药情况以及头发健康/病史的问卷。在头皮顶点处进行单次拔发试验。
每次拔发的平均脱发数为 0.44（SD 0.75）。参与者洗发（P=.20）或梳头（P=.25）时间对平均脱发数无显著影响。白种人、亚洲人和非裔人群的头发质地不同，但拔发试验值无显著差异。服用影响脱发药物的参与者与未服用这些药物的参与者的拔发值无显著差异（P=.33）。紧束发型对拔发试验值无影响。
研究期间无法控制参与者的洗发和梳头情况，但已记录并分析了这些信息。
正常的拔发试验值应减少至 2 根或更少（97.2%的参与者）。目前对试验前 5 天的洗发限制可以放宽，梳头也可以允许。
