| Black piedra
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. | |