The following terms are defined in order to obviate any confusion that may exist on the part of the reader concerning the nomenclature of the subject of this article.
Trichorrhexis nodosa, as the name implies, is characterized by the presence on the shaft of the hair of one or more irregularly spaced, small, grayish nodes, which suggest nits. Microscopically, these nodes at that point show a longitudinal splitting of the hair resembling two small paint brushes pushed together end to end (fig. 1).
Trichoclasia, essentially a later stage of trichorrhexis nodosa, is the transverse fracture of the shaft of the hair occurring at the middle of the nodes, as a result of the hair losing its resistance to traction at that point (fig. 2).
Trichoptilosis is the longitudinal splitting of the shaft of the hair into numerous long fibrils in the shape of a feather.
The etiology of the disease