Causes of Psoriasis

Recent research indicates that psoriasis is a disorder of the immune system. The immune system includes a type of white blood cell, called a T cell, that normally helps protect the body against infection and disease. Scientists now think that in psoriasis, an abnormal immune system causes activity by T cells in the skin. These T cells release substances called cytokines that trigger the inflammation and excessive skin cell buildup of psoriasis.

People with psoriasis may notice that there are times when their skin worsens, then improves. Conditions that may cause flare-ups include changes in climate, infections, stress, and dry skin. Also, certain medicines such as beta-blockers, lithium, and some other drugs may trigger an outbreak or worsen the disease.