Vellus hairs in the frontal scalp in early female pattern hair loss.

BACKGROUND: Dermoscopy of the scalp (trichoscopy) is a technique to evaluate the skin of the scalp and the hair disorders. It clinically helps to establish early female pattern hair loss (FPHL) without the need for more invasive techniques.
OBJECTIVES: This work intends to demonstrate new adjunct criteria for the clinical diagnosis of FPHL by determining the number of short vellus hairs encountered in the frontal area of the scalp of female patients with FPHL.
MATERIALS AND METHODS: We retrospectively reviewed the trichoscopy images from 45 women affected by FPHL in initial stages, at 20 fold magnification dermoscopy at 2 cm from the hairline into the frontal area of the scalp.
RESULTS: A total of 45 patients images included had more than 20% variability at dermoscopy, criteria utilized to diagnose and included them in the study. All patients were graded as Ludwig I severity, 14 patients had frontal accentuation. The average number of vellus hairs in the frontal area at 20-fold magnification of all patients was of 12.02 vellus hair in the frontal area. When comparing the Ludwid I pattern group versus the Ludwig I with frontal accentuation pattern group there was no statistical difference between the two clinical groups.
CONCLUSIONS: All 45 patients analyzed in this study were clinically diagnosed with FPHL. The number of vellus hairs in the frontal area was greater than the average found in normal subjects. Most patients (80%) with FPHL had more than or equal to seven vellus hairs per 20-fold magnification field in the frontal area, therefore we suggest that the presence of more than 6 vellus hairs in the frontal scalp at 20-fold magnification can be used as an additional criterion of FPHL.

INTRODUCTION

Dermoscopy of the scalp (trichoscopy) is a technique to evaluate the skin of the scalp and the hair disorders. It assesses the hair follicle and the hair shaft at high magnifications up to ×160.[123456]

Dermoscopy of the scalp (trichoscopy) has been established as a very useful tool to diagnose early female pattern hair loss (FPHL).

The dermoscopic hallmark of the disease is the presence of more than 20% hair diameter diversity (variability), which is the dermoscopic evidence of follicle miniaturization.[7]

Some of the authors have coined the term “anisotrichosis” to describe this variation in hair diameter.[8]

Other dermoscopic signs of early FPHL are the peripilar sign, which reflects the presence of perifollicular lymphocytic infiltrates[910] and an increased number of vellus hairs in comparison to healthy volunteers (20.9% ± 12% vs. 6.15% ± 4.6% respectively).[10]

In cases of advanced AGA follicular units with only 1 hair predominate.[2] Empty follicular ostium filled with sebum and keratinous material can be observed as yellow dots[2356] and a honeycomb pigmentation is indicative of sun exposure.[3]

Recently, white peripilar sign and focal atrichia have been described in advanced cases in Chinese patients. White peripilar sign is thought to be due atrophy present in long-standing cases and is associated with a poor response to treatment.[11]

In 2009, Rakowska et al. proposed 3 major and 3 minor diagnostic dermoscopic with a 98% specificity for the diagnosis of FPHL.[10]

The major criteria were the following: more than four yellow dots in four fields decreased average shaft thickness and more than 10% of thin hairs (<0.03 mm) in the frontal area. Minor criteria included the following: perifollicular discoloration, increased single-hair pilosebaceous units and increased percentage of vellus hairs in the frontal area compared with the occiput.

The objective of this paper is to determine the absolute number of short vellus hairs in the frontal scalp in patients with early AGA, since percentages are not easily calculated in everyday life. In 2009, Rakowska determined that the normal number of short vellus hairs in the frontal area of healthy individuals in 20-fold magnification is 2 vellus.[12] We expect to find more than 2 short vellus hairs in patients with AGA due to the miniaturization of terminal hairs.

MATERIALS AND METHODS

We retrospectively reviewed the trichoscopy images consecutively obtained in a 4 month period from 45 women affected by FPHL in initial stages, namely Ludwig I with and without frontal accentuation. Images were obtained with a videodermatoscope (FotoFinder Systems GmbH, Germany) at magnification of ×20, at 2 cm from the hairline into the frontal area of the scalp. The same image was also evaluated at ×70 for measurements.

Three independent dermatologists reviewed the images from the frontal scalp and counted the number of vellus hairs in one field of vision at a 20-fold magnification. Vellus hairs were identified as thin short hairs interspaced amongst normal and thinner hairs [Figure 1]. The criteria to count vellus hairs included visualization of the hairs emergence and measuring the hairs that were less than 0.03 mm in diameter and less than in 2 mm length ×70 magnification by the FotoFinder software Dermoscope Dynamic (FotoFinder Systems GmbH, Germany).

Figure 1

Vellus hairs in frontal scalp

RESULTS

Totally 45 patients were included in this study. All patients had more than 20% variability of hair diameter at dermoscopy, criteria utilized to diagnose and include them in the study. Their age ranged from 18 to 70 years. The mean age was of 37,82 (38 ± standard deviation [SD]) years.

All patients were graded as Ludwig I severity. Fourteen patients (31%) had the Ludwig I with frontal accentuation pattern and 31 patients (68%) had the Ludwig without the frontal accentuation pattern.

The average number of vellus hairs in the frontal area at 20-fold magnification of all patients was of 12.02 ± 6.51 vellus hairs in the frontal area and the SD was of ±6.51. For patients without frontal accentuation, the mean number of vellus hairs was 11.13 ±SD. For patients with frontal accentuation it was 14 ±SD. Most of the patients could be found within 1 SD from the mean. When comparing the Ludwid I pattern group (mean = 11.13) versus the Ludwig I with frontal accentuation pattern group (mean = 8.41) after a Student's t-test comparison analysis we found no statistical difference between the two clinical groups [Figure 2].

Figure 2

Number of vellus hair according to clinical variants

CONCLUSIONS

All 45 patients analyzed in this study were clinically diagnosed with FPHL. The number of vellus hairs in the frontal area was greater than the average found in normal subjects for both patterns Ludwig I and Ludwig I with frontal accentuation. The mean number encountered was of 12.02 ±SD vellus hairs for all patients with FPHL. Most of the patients (80%) with FPHL had more than or equal to seven vellus hairs per 20-fold magnification field in the frontal area. Because it is easier to count the absolute number of vellus hairs than their percentage in the everyday practice, we suggest that the presence of more than 6 vellus hairs in the frontal scalp at 20-fold magnification can be used as an additional criterion of FPHL, especially in the initial phases of the disease.