Psoriasis - chronic dermal disease at which are amazed a skin, fingernails, joints.

Virus, hereditary, neurogenic, metabolic theories of a parentage of a psoriasis are most widespread, any of which is not conventional. Apparently, disease has the multifactorial nature. In a pathogenesis the certain role allocate to immunologic, enzymatic and other biochemical disturbances.

The clinical picture in typical cases is characterized by occurrence of the monomorphism papular eruption located in basic on the elbows, a trunk, a pilar part of a head. Sharply circumscribed papules in diameter from 2-3 mm up to 1-2 centimeters of red color of spherical outlines, act above a surface of a skin a little, are covered by siver-white flakes. The resorption of plaques usually begins with the central part therefore psoriasis elements get the annular form. On places of the resolved rashes there is a time depigmentation (pseudo-leiodermia). During the periods of incomplete remissions on separate sites of an integument (more often in the field of ulnar, knee joints) there can be individual "on duty" plaques.