Psoriasis is a term derived from the Greek word psōra which means itch and is a common, chronic inflammatory skin condition which affects 1-3% of the UK population and about 80 million people worldwide. Psoriasis is a non-infectious, multi-factorial condition which involves genetics, the immune system and environmental triggers that results in inflammation, itching and the formation of red, raised plaques, with silvery-white scales and well-defined edges on the surface of the skin. These plaques vary in both shape and size and can dry and crack making the skin feel sore.