Establishment and validation of a hair fall atlas for Chinese men based on trichoscopy

Hair loss is among the top concerns for Chinese men. Current clinical diagnosis is based on the Hamilton-Norwood classification as a macroscopic tool to recognise different severity levels and the phototrichogram (PTG) to show hair regrowth status within a shaved zone. However, it has limited dynamics and sensitivity to assess consumers with mild hair loss problems or at the early onset of hair loss. Therefore, we aim to develop a zoom-in hair fall atlas based on trichoscopy to better evaluate consumer hair fall problems.

Four hundred healthy Chinese men with different hair fall severity of Hamilton-Norwood classification are recruited, pictures collected and scalp measurements conducted in a total of 3 days. Later, 5 dermatologists will select representative images to build the atlas and score the rest of the images accordingly.

A hair fall atlas based on scalp micro images was established, with 7 grades to represent the wide variety of consumer hair-fall severities. Each dermatologist scored images that covered all the grades. Good consistency was achieved between the 5 dermatologists (Pearson correlation coefficient >0.8). Our results also showed great repeatability between two scores of the same dermatologist (intraclass correlation coefficient >0.9). In addition, a strong correlation was shown between clinical scores and hair fall attributes of scalp visibility % and hair diameter based on image analysis (|p| > 0.8).

The FISHS hair fall atlas is well-established, validated and ready to be incorporated as a new methodology to guide anti-hair fall evaluation and aid in product development.