Psoriasis is a chronic condition believed to be an autoimmune disease of the skin that causes the skin cells to build up as much as 10 times faster than unaffected skin. The overabundance of skin cells causes patches of skin that appear red, scaly and raised, most commonly on the knees, elbows, scalp and torso. These patches are typically dry and may itch, crack or bleed. Thick nails that are pitted or have ridges may also be a symptom of psoriasis. Depending on the type of psoriasis diagnosed, symptoms may be present early in childhood or may develop when triggered by infection, trauma or some medications. There is no known cure for psoriasis, however there are some effective treatments that may stunt the growth of skin cells to offer relief.