pityriasis rubra pilaris

[pĭ-lârĭs]
n.
  1. A chronic eruption of the hair follicles, which become firm, red, surmounted with horny plugs, and often form scaly patches.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.