The scaling caused by psoriasis occurs when cells in the outer layer of skin reproduce faster than normal and pile up on the skin's surface. Psoriasis' severity ranges from minor, covering just a few small areas, to severe, disabling cases that can involve the entire body.
Treatments generally aim at slowing rampant growth of skin cells.
Arnold W. Gurevitch, M.D., chief of dermatology at USC, says that over the past few years, researchers have been able to improve some older treatments and have also found new methods of alleviating troublesome symptoms. Topical steroids, ointments or creams used most commonly to treat psoriasis are much stronger and more effective than they were just a few years ago. Within the last five years, the U.S. Food and Drug Administration approved a powerful non-steroidal ointment called Dovonex, known generically as calcipotriene, for moderately severe cases of psoriasis. And for some people treatments begin to lose their effectiveness over time. Gurevitch says that recent research points to psoriasis as a kind of immune disorder in which the body's white blood cells produce chemicals that stimulate skin cells to proliferate.