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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



(also called trichosporosis), a fungal disease of the hair caused by many varieties of the genus Trichosporon, one of the keratomycoses. In piedra, the hair shafts bear numerous barely perceptible spindle-shaped whitish to dark brown nodules with a distinctive pungent odor; the nodules consist of spores of the fungus. The hairs remain intact and there is no skin inflammation.

The American variety of piedra (black piedra) affects mainly women and infests only the scalp. The European form (white piedra) infests the beard and moustache. Piedra is not highly contagious; infection may occur through using a towel, hat, or comb used by an infected person. The infection becomes worse if the hair is washed with flaxseed extract or if the oil of repeinik roots (seeREPEINIK) is applied to the hair, since both substances supply nutrients to the causative agent.

Piedra is treated by shaving the affected areas, washing them with hot water and soap, and applying a 0.1–0.2 percent solution of mercury bichloride. Observance of the rules of personal hygiene is the best means of preventing the disease.


Mnogotomnoe rukovodstvo po dermato-venerologii, vol. 2. Leningrad, 1961.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Melanie Perez Ortiz, Universidad de Puerto Rico--Rio Piedras
Un formato similar se advierte en la guia de Piedras Blancas al abordar 137 especies, pero mas profusamente ilustrada en morfologia, ciclos de vida y estados inmaduros de especies de la region que son descritos algunos por primera vez (eg.
Estas ideas explican el fervor con el que Mutal realizaba los pagos de tierra antes de extraer las piedras, ya que era un conflicto interno violar el orden natural del espacio al alterarlo.
En ese sentido, abordamos el estudio de uno de los materiales que puede indicar la existencia de esas actividades, como son las piedras bezoares producidas por animales.