Spider veins: Also known as telangiectasias, are damaged veins. We develop varicose veins when tiny, one-way valves inside the veins weaken, and some blood flows backward and accumulates in the vein. Extra blood in the vein puts pressure on the walls of the vein. With continual pressure, the vein walls weaken and bulge. In time, we see a varicose or spider vein. Risk of developing varicose and spider veins is increased if you have blood relatives that have them, if you sit or stand for long periods most days of the week, with increasing age and during pregnancy. Spider veins can also be caused by sunlight, hormonal changes, or an injury. Dr. Ling utilizes sclerotherapy or lasers for spider veins. For anything larger than 1 mm in diameter, we recommend you seek the care of a vascular surgeon for varicose veins.