The Trichoscopy Derived Sinclair Scale: Enhancing visual assessment through quantitative trichoscopy

Abstract

Introduction: The Sinclair Scale of hair midline density is commonly used in clinical dermatology practice as a tool to evaluate the severity of female pattern hair loss (synonym androgenetic alopecia, AGA) and to monitor patient response to treatment. The Sinclair Scale involves a visual evaluation of central hair parting line width, that is performed quickly and with no optical instrumentation. Another approach used to score severity of hair loss is quantitative trichoscopy. While quantitative trichoscopy is more accurate in terms of reproducibility and objectivity, it is more time-consuming.

Materials and methods: Patients with different stages of AGA were evaluated using both the Sinclair Scale and quantitative trichoscopy. A correlation analysis was performed between the Sinclair Scale and different parameters derived from statistical analysis of trichoscopy images. A novel parameter, cumulative hair thickness density was introduced.

Results: Very good correlation was observed between Sinclair Scale and the cumulative hair thickness density. The quality of correlation is sufficient to estimate Sinclair Scale from cumulative hair thickness density. A formula to calculate the 'Trichoscopy Derived Sinclair Scale' from trichoscopy statistics was derived.

Discussion: We propose the term 'Trichoscopy Derived Sinclair Scale' to describe the hair midline density as derived from trichoscopy and to differentiate this assessment of midline hair density from the traditional one based on visual inspection alone.

Keywords: Sinclair Scale; androgenetic alopecia; dermoscopy; female pattern hair loss; hair thickness; quantitative trichoscopy.