piedra involving the hairs of the scalp, caused by Piedraia hortae and characterized by firmly adherent black, hard, gritty nodules composed of an organized, firmly cemented mass of fungus cells; the fungal growth is always located above the level of the hair follicles; the disease occurs in humid tropical areas of the Americas, Africa, and Asia, and attacks chimpanzees and other primates as well as humans.
Farlex Partner Medical Dictionary © Farlex 2012
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.
black Pi·e·dra(blak pē-ā'dră)
A fungal infection that affects the hair shaft; hard, gritty, brown-to-black crusts composed of hyphal elements are characteristic features; common in tropic areas. Piedraia hortae is the causative agent.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012