TrichoScan: combining epiluminescence microscopy with digital image analysis for the measurement of hair growth in vivo.

Hair loss or hair thinning is a common complaint in clinical dermatology, and patients seeking advice for hair loss are not necessarily bald. Also the effects of treatment attempts are hard to measure. Consequently, there is a need for a sensitive tool to monitor hair loss and treatment response. Such a method must be able to analyze the biological parameters of hair growth, which are: 1: hair density (n/cm2), 2: hair diameter (mm), 3: hair growth rate (mm/day) and 4: anagen/telogen ratio. Here we present the TrichoScan as a method which combines epiluminescence microscopy (ELM) with automatic digital image analysis for the measurement of human, and potentially animal hair, in situ. The TrichoScan is able to analyze all biological parameters of hair growth with a so-called intraclass correlation of approx. ninety-one percent with the same TrichoScan operator and an intraclass correlation of approx. ninety-seven percent for different TrichoScan operators. The application of the technique is demonstrated by comparison of the hair parameters in individuals without apparent hair loss with men with untreated AGA and men after treatment with finasteride (1 mg/day), where we were able to detect a significant increase in hair counts and cumulative hair thickness 3 and 6 months after treatment. The advantage of the TrichoScan is that it can be used for clinical studies to compare placebo versus treatment or to compare different capacities of different hair growth promoting substances, it can be used for studying AGA or other forms of diffuse hair loss, and it can be adopted to study the effect of drugs or laser treatment on hypertrichosis or hirsutism.