Extracorporeal systems for the treatment of psoriasis

Psoriasis is a chronic skin disease sometimes resistant to the conventional therapy of ultraviolet radiation, retinoids, or antimetabolites. The description of immunologic and biochemical disturbances prompted several authors to use extracorporeal methods for treatment of this disease.

Plasma exchange gave only partial and brief remissions, and a controlled study noted no beneficial effect from sham and true apheresis. Leukocytapheresis may lead to more significant remissions, but no controlled studies have been performed.

The results concerning dialysis therapy remain conflicting, and controlled studies have reached opposing conclusions. The mechanism of action of extra-corporeal therapy is unclear, and it should only be considered for very resistant psoriatic patients.