S8   HAIR GROWTH AND HAIR LOSS: A TECHNICAL CHALLENGE FOR THE CLINICIAN.

Van Neste D. Skinterface sprl, Tournai, and H.A.I.R. Technology®, Brussels, Belgium

From the technological point of view the clinician operates in a very complex field. Indeed the asynchronous scalp hair root activity contributes to an apparently stable global mass of hair. Considering the wide range of the length of anagen phase (long terminal hair - barely visible vellus like hair), one realises the difficulty of defining a simple procedure that would encompass all information in a nutshell.

Basically four variables will condition the hairiness of any given body site at any time: hair density, duration of anagen, linear hair growth rate and diameter. On the scalp telogen duration appears to be rather stable while anagen duration may fluctuate enormously during lifetime. In androgenetic alopecia while the quality of hair replacement is gradually less satisfactory, the lag time between hair shedding and re-growth also contributes significantly to the lack of scalp coverage by visible hair. More subtle factors such as hair distribution pattern, root angle, shaft shape, pigmentation, contrast with background, shine, oiliness…are important in terms of perception and styling. These factors play a significant role in the evaluation of scalp skin coverage or global satisfaction with hair.

Over the last 10 years we have conducted several comparative trials between less invasive methods including various photographic methods (lenses or scalp preparation procedures) and more invasive methods (hair plucking and scalp biopsies). The contribution of such sophisticated methods in the field of clinical research will be highlighted. As the PTG has reached the appropriate standards of quality, new observations of phase transitions i.e. anagen to catagen – telogen and telogen to anagen can be detailed.