Background: Currently, the gold standard to assess the severity and distribution of terminal hair growth is formed by the modified Ferriman-Gallwey (mFG) score. However, this scoring system has its limitations: current assessment requires a full body exam as well as restraint of hair removal methods and previous studies have shown large inter-observer variations when using the mFG score. Thus, a more objective and patient friendly method is essential for the quantification of terminal hair growth in cases of hirsutism and gender dysphoria.
Objectives: The primary aim of this study was to semi automatically evaluate the severity and distribution of terminal hairs on images made with a digital microscope camera. The secondary aim of this study was to evaluate the applicability of this script on both phantoms and participants.
Methods: In this study, we created a script in MATLAB to semi automatically assess hair density, hair thickness and hair color on images made with the Dino-Lite Pro digital microscope. Therefore, we compared values obtained from the script with manually assessed values. We developed 15 phantoms with variation in hair density, hair color and hair thickness and used them, together with data obtained from 28 male participants, to validate the script.
Results: Analysis of the clinically relevant data (e.g. short hairs) in the study with participants showed mean hair density deviations between manual and digital assessment of -2.2 hairs/cm2 (week 1) and 1.2 hairs/cm2 (week 2) and mean hair thickness deviations of -8.1 µm (week 1) and -11.1 µm (week 2), suggesting the script has a standard deviation of 1.7 hairs/cm2. Hair colors can be distinguished from each other by means of pixel values, whereby pixel values represent either light or dark colored hair.
Conclusions: The script can adequately measure hair densities and pixel values that can be converted into hair shades, yet assessment of hair thickness showed inconclusive results. The script is also better at the quantification of short hairs, which is preferred regarding patient friendliness.