Phlebitis on the arm of a 75 year old male patient arm after the insertion of an intravenous (IV) cannula. Phlebitis is an inflammation of a vein that causes a painful, swollen and hot area on the skin. It usually develops after a mild trauma to a vein such as having an IV line. It is not typically serious and often gets better on its own after a couple of weeks. Treatment can include anti-inflammatory drugs and the wearing of support bandages.