Psoriasis

(so-ri'-as-is). Lepra alphos; Lepra; Dry Tetter; Psora; a common chronic inflammatory disease of the skin, characterized by variously-sized lesions having red bases, covered with white scales resembling mother-of-pearl. It affects by preference the extensor surfaces of the body. The lesions are infiltrated, elevated, clearly defined, covered with white, shining, easily-detachable scales, which upon removal reveal a red, punctate, bleeding surface. The eruption is absolutely dry, and itching is usually absent. The etiology is obscure, though heredity plays a considerable role in its production. P. annular is. Synonym of P. circinata. P., Buccal, P. buccal is. Synonym of Leukoplakia buccal is. See also P., Lingual. P. centrifuga, psoriasis in which the patches heal in the center while spreading at the periphery. P. circinata, psoriasis in which the central part of the lesions has disappeared, leaving ring shaped patches. P. diffusa, a form in which there is coalescence of large contiguous lesions. P. disco idea. Same as P. nummular is. P., Eczematous, an acute form with bright red patches, le defined at the margin than usual, with thin and papery scales, which are thrown off so rapidly that they have no time to aggregate into ma es. The part is hot and tender, itches severely, and very little irritation will produce discharge. P. empyodes, a form in which a little pus forms underneath the crusts; a rare event. P. figurata, P. geographic a, psoriasis in which the patches are arranged in irregular patterns. P. guttata. See P. punctata. P. gyrata, psoriasis with a serpentine arrangement of the patches. P. inveterata, a very obstinate form in which the skin is much thickened and fi ured, with large adherent scales. P. nigra, a variety of psoriasis in which deep pigmentation has taken place. P. nummular is, P. nummulata, psoriasis in which the patches develop in the shape and size of coins. P. ophthalmic a, squamous eczema of the eyelids. P. orbicularis. Synonym of P. circinata. P. palmae, a dry eczema of the hands, or a squamous syphiloderm. P. palmar is et plantar is syphilitic a, a squamous syphiloderm of the palms and soles. P. pilar is, a form affecting the region of the hair-follicles. P. punctata, a form in which the lesion consists of minute red papules which rapidly become surmounted by pearly scales. These spread peripherally and soon resemble drops of mortar (P. guttata); when they attain the size of a coin the name P.