Psoriasis is a chronic skin condition characterised by inflammation and scaly skin. People with psoriasis have an increased production of skin cells, about 5x faster than normal. The cause of psoriasis is not well understood but is thought to be related to the immune system. It usually starts in response to a trigger which could be an injury to the skin, a throat infection or using certain medicines. It is not contagious and there is no cure, but there are treatments that can improve symptoms.