psoriasis

(so-ri'a-sis) [G. psoriasis; psora, the itch.] A skih disease consisting in an eruption of circumscribed rounded patches of a red color covered with adherent white scales, occurring chiefly on the extensor surfaces of the elbows and knees, the scalp, and the back. p. annul a'ris, p. annul a'ta, p. circinata. p. bucca'lis, leucoplakia. p. circina'ta, p. in which healing is taking place at the center while the proce continues at the periphery, producing a ring-shaped lesion, p. difiu'sa, diffused p., a form with more or le coalescence of the lesions, p. gutta'ta [L. gutta, drop], p. occurring in roimd patches of small size, giving tha appearance of a rain-bespattered surface. p. gyra'ta, p. circinata in which there is a coalescence of the rings giving rise to figures of various outlines, p. invetera'ta, a form in which the lesions are confluent, the affected skin being thickened, indurated, and scaly, p. lin'guae, leucoplakia. p. nummula'ris, p. with flat elevated lesions the size of a quarter or of a half-dollar. p. orbicula'ris, p. circinata. p. puncta'ta, p. in which the individual lesions are papules, each red in color, and tipped with a single white scale, p. Tupioid'es, a form in which crusts resembling rupia are formed on the skin. p. univeisa'lis, generalized p.