1835-45; < New Latin < Greekpsī́lōsis literally, a stripping bare, equivalent to psīlō-, variant stem of psīloûn to strip (derivative of psīlós bare, smooth) + -sis-sis
"loss of hair through disease," 1837, medical Latin, from Greek psilosis "a stripping of hair," from psiloun "to strip of hair," from psilos "bare" (see psilo-).