F22 EXOGEN HAIR SAMPLING: CLINICAL INTEREST OF ‘’STICKY HAIR’’ MEASUREMENT
Van Neste D, Leroy Th, Conil S, Parys MP, Warrand MF, Ronsse V
Skinterface, Tournai, Belgium

A method for collection of loosely attached elements has been developed for specifically sampling exogen hair. A single or repeat application is possible either without clipping the hair or in combination with our contrast-enhanced phototrichogram (CE-PTG) technology. After a preliminary study on 19 subjects, 42 male subjects with patterned baldness (MPB) were evaluated (top of the head). After clinical severity rating (Hamilton stages I-II (n=13), III (n=14) and IV-V (n=15)), we performed a global scalp coverage scoring (SCS method), collected exogen before (n=17) or after (n=25) CE-PTG. With increasing severity of MPB, SCS was decreasing (r= 0.702) as were thick (>40?m) hair counts (r=0.728) and anagen hair % (0.688) while the density (r= 0.534) and the proportion of thinner hair (thickness=40 ?m; r=0.731) was increasing. Exogen as a % of total hair counts amounted up to 34%, which reflects disease activity and correlated with clinical severity (p<0.05). Hence, as exogen hairs are sampled at the exclusion of telogen hair - telogen remain anchored to the surrounding follicular structures - anagen % identified with the “exogen-free”-CE-PTG technique reflects the probable duration of anagen. As MPB increases in severity, i.e. stages I-II, III and IV-V respectively, the % anagen of thicker hair drops from 74 to 63 or 57% indicating a dramatic shortening of hair cycle duration (49, 32 and 23% for thin anagen hair respectively). These findings support a gradual reduction of hair follicle productivity i.e. shortening of anagen duration of terminal type follicles before precipitation into miniaturisation.