Rebora Alfredo, Guarrera Marcella, Drago Francesco, Rossi Alfredo, Fortuna Maria Caterina, D'Ovidio Roberto, Chieco Paolo, Piraccini Bianca Maria, Starace Michela
DISSAL, Section of Dermatology, IRCCS Azienda Universitaria Ospedaliera San Martino-IST, Genoa, Italy.
Department of Internal Medicine and Medical Specialties, University La Sapienza, Rome, Italy.
Int J Dermatol. 2016 Jan;55(1):e7-e10. doi: 10.1111/ijd.13088. Epub 2015 Oct 16.
In clinical trichology, reference values are often arbitrary. The difficulty in setting them up depends mostly on the presence of the androgenetic alopecia (AGA) genotype in subjects with clinically unapparent forms. Prepubertal children, who lack 5α-reductase (a real indicator of the AGA phenotype), might provide reference values independent from AGA. We verified whether the vertex/occiput ratios (V/O) of hair density and the V/O of hair diameter are suitable parameters.
In sixty 4-10-year-old Caucasian children, we measured the ratio between the hair density at the vertex and the occiput. The same was done for the diameter.
The V/O of density averaged 1.07 ± 0.17 and the V/O of diameter 1.02 ± 0.11.
Taking the mean ± 2SD as normal values, our "normal" V/O of density ranged between 0.73 and 1.41 and our "normal" V/0 of diameter between 0.8 and 1.24. People with lower ratios would have, therefore, AGA with 95% of probability. Moreover, we found that hair shedding using the hair pull test and the modified wash test come to 1-2 hairs/day.
在临床毛发学中，参考值往往是随意确定的。确定这些值的困难主要取决于临床症状不明显的受试者中雄激素性脱发（AGA）基因型的存在情况。青春期前儿童缺乏5α-还原酶（AGA表型的一个真实指标），可能会提供独立于AGA的参考值。我们验证了头顶/枕部毛发密度比（V/O）和毛发直径V/O是否为合适的参数。
在60名4至10岁的白种儿童中，我们测量了头顶和枕部的毛发密度之比。对毛发直径也进行了同样的测量。
密度的V/O平均值为1.07±0.17，直径的V/O为1.02±0.11。
以平均值±2标准差作为正常值，我们的密度“正常”V/O范围在0.73至1.41之间，直径“正常”V/O在0.8至1.24之间。因此，比值较低的人患AGA的概率为95%。此外，我们发现使用拔毛试验和改良洗发试验测得的脱发量为每天1至2根头发。
