T. Leroy and D. Van Neste.
Skinterface sprl, Tournai, Belgium and Hair Technology, Brussels, Belgium
Study Information and Results:
In male androgenetic alopecia (AGA), global changes of scalp hair observed on many years are the result of discrete structural and/or functional modifications at the level of individual hair follicles. The aim of this study was to evaluate correlation between hair density, percent of thin hair and clinical staging. 5 controls (C) and 21 untreated male subjects with androgenetic alopecia (16-51 years) were examined and classified according to a modified Norwood-Hamilton scale (9 stage I-II ; 9 stage III and 3 stage V). Scalp photographs (primary enlargement x 3) were taken in all subjects on 3 anatomical sites (fixed coordinates on the left and right side of the top of the head and one occipital).
Hair counts were obtained from two different photographic procedures i.e. before and after contrast enhancement (CE). Percentages of thin hair (< 40um) were obtained after microscopic measures on clipped hair. We observed more scalp hairs after contrast enhancement (p<0,0001). Significant differences of extra hair (n/cm 2) were detected specifically between groups (p=0,0002) on top of head (C +29; AGA +60) as opposed to the occipital site (C +29; androgenetic alopecia +33).
On the top of the head, we observed a decrease of hair density with both photographic methods (controls > I -II = III > V; p<0,05) and an increase of thin hair (I -II = III < V; p<0,0001) in correlation with the Hamilton severity score while no changes were recorded in the occipital site. The extra 60 hairs observed after CE in androgenetic alopecia (top of head) reflects probably a mixed population of thin and less colored hair already engaged in the “miniaturisation process” usually undetected without CE.
The density changes occur at an early stage of androgenetic alopecia while the top of the head is not yet clinically affected (severity grades I – III). The more drastic decreases of density in the more severely affected patients (V) are consistent with hair thinning and the clinical observation of an expanding wave of follicular hypotrophy.