THE PHOTOTRICHOGRAM - ANALYSIS OF SOME TECHNICAL FACTORS OF VARIATION

Photographic methods for hair evaluation are frequently proposed as an alternative to more invasive methods (trichogram or biopsy). The reli ability in terms of quantitative follow-up of hair growth has not been evaluated properly. We report results of comparative studies of scalp hair evaluation with various photographic methods. Statistically sign ificant findings were a better detection of scalp hairs using the orig inal enlargement x 3 as compared to x 2 (212 vs. 167 hair follicles/cm 2) and a more acceptable estimate of linear hair growth rate with 'sca lp immersion proxigraphy' (SIP) (0.317 mm/day) as compared with classi cal phototrichogram pictures where this variable was underestimated by 30% on average (0.27 mm/day). SIP-generated linear hair growth rates were very close to the micrometric method (0.37 mm/day). Therefore SIP x 3 images appear preferable for hair growth monitoring during clinic al trials.