Pathogenesis in Pili Torti: Morphological Study

July 1994 in “ Journal of Dermatological Science ”

Tomohiro Maruyama, Masahiko Toyoda, Akihiro Kanei, Masaaki Morohashi

pili torti hair disorder outer root sheath inner root sheath hair shaft

TLDR Pili torti hair twists due to uneven outer root sheath cell development.

The study investigated the morphological abnormalities in pili torti, a hair disorder, using various microscopy techniques and 3-D analysis. It found that the hair shafts were partly flattened and twisted, with disruptions occurring at various points. The outer root sheath (ORS) showed irregularities in thickness and cell arrangement, which were linked to the twisting of the hair. The inner root sheath (IRS) also displayed irregularities, contributing to an uneven hair shaft. These findings suggested that unequal development of ORS cells led to the characteristic twisting of hair in pili torti.