Background: TrichoScan(®) is considered to be time-saving, easy to perform and consistent for quantifying hair loss/growth. Conflicting results of our study lead us to closely observe the image analysis, and certain repeated errors in the detection of hair were highlighted.
Aims: To assess the utility of TrichoScan in quantification of diffuse hair loss in males with androgenetic alopecia (AGA) and females with diffuse telogen hair loss, with regard to total hair density (THD), telogen and vellus hair percentages.
Materials and methods: TrichoScan procedure was performed on 77 cases and 20 controls.
Results and discussion: In the cases, THD decreased with increasing severity of alopecia. Surprisingly, more than 85% of the healthy volunteers had an unexplained abnormal telogen hair percentage of more than 20. Also, the telogen hair percentages were not significantly different between cases and controls. Also, 65% of the patients with advanced thinning of hair did not have the expected elevation of vellus hair percentages on TrichoScan evaluation. Multiple errors were highlighted in hair detection by the software. Errors were noted at the exit points of follicular ostia, at places where hair strand thickness was not uniform throughout its length, where there was crossing, overlapping of the neighboring strands, and when more than one hair emerged from a single ostium.
Conclusion: TrichoScan is promoted as a validated and precise tool for measurement of hair growth parameters. Under certain conditions, it may seem suitable for clinical trials evaluating treatment response. We provide evidence that this is an overstatement. This study concludes that TrichoScan-analyzed anagen/telogen hair detection is not optimal; moreover, there is overestimation of THD and the vellus hair percentage does not correlate with clinical severity of alopecia. The current form of TrichoScan, though easy to use, is error-prone and awaits refinement.
Keywords: Computer-assisted image analysis; TrichoScan®; digital image analysis; methodology; systematic errors.