Dh. Rushton et al., COMPARATIVE-EVALUATION OF SCALP HAIR BY PHOTOTRICHOGRAM AND UNIT AREATRICHOGRAM ANALYSIS WITHIN THE SAME SUBJECTS, Acta dermato-venereologica, 73(2), 1993, pp. 150-153
Quantitative evaluation of scalp hair requires techniques that are rep
roducible. The unit area trichogram is such a method but is unsuitable
for large-scale clinical trials. An alternative may be the phototrich
ogram - a non-plucking, non-invasive method. Hair variables were evalu
ated in 12 Caucasian subjects employing both methods. The mean value f
or total hair density was significantly underestimated by the phototri
chogram (181 versus 237 hairs/cm2); however, no significant difference
was found between this phototrichogram value and the number of non-ve
llus hairs/cm2. Estimates for the percentage of anagen hairs were simi
lar with both methods. Hair diameters from the phototrichogram were to
o unreliable to be of any practical use. Analysis of the individual ha
ir data revealed that light hair was much more difficult to evaluate t
han dark hair. Consequently, Caucasian subjects with light hair or dar
k skin subjects with dark hair should be excluded from studies employi
ng phototrichograms.