L-22   SIGNAL VERSUS NOISE: THE INTEREST OF NEW METHODS FOR HAIR GROWTH - HAIR LOSS MONITORING IN HUMAN SKIN IN VIVO

D. Van Neste Skinterface, Tournai, Belgium.

Global changes of scalp hair represent the cumulative end result of discrete changes of individual hair follicle dynamics. Detailed monitoring of such changes in any hair disorder including androgen dependent hair loss -androgenetic alopecia- requires an accurate non-invasive method. After identification of the shortcomings of existing methods, a new phototrichogram (PTG) using contrast enhancement (CEPTG) has been developed. Scalp surface images were compared pairwise with scalp histology and severely miniaturised hair fibre (down to 8 µm diameter), all growth stages and transitions -anagen, catagen and telogen- as well as empty follicle stage (exogen) were clearly recorded. Hence, besides dynamic non-invasive exploration, the analysis of 2 images generates as much information as examining total serial sections of scalp biopsies. A global approach (Scalp Coverage Scoring, SCS; application patent PCT/EP/ 01/0697) has also been developed and calibrated with this CE-PTG technique. Clinically significant changes such as worsening on placebo and improvement on active treatment has been quantified such that this instrumental method can now be safely applied in multicenter clinical trials before routine application in individual hair clinics. The initial stages of androgenetic alopecia show a sequence of gradual shortening of the duration of anagen followed by hair thinning. This regressive process results in an almost irreversible stage with extreme hair follicle miniaturisation and negligible hair production.