Spider veins are blood vessels that appear on the body, particularly the legs and occasionally the face or elsewhere. They occur in both men and women, but occur most frequently in women. The cause of spider veins is thought to be primarily genetic, but estrogen may play a role in their development, as they are noticed more frequently after puberty, pregnancy, or using oral contraceptives. Spider veins may occur in association with underlying varicose veins. When they occur on the face, spider veins may be related to chronic sun exposure. Spider veins can be treated in most cases. Those that appear on the face can be treated with lasers. Leg veins are treated with a procedure called sclerotherapy (sclair-oh-THARE-ah-pee). A solution, called a sclerosing (SCLAIR-rosing) solution, is injected with a very fine needle directly into the blood vessel. The solution irritates the lining of the vessel causing it to swell and close off. Over a period of several weeks, the vessel fades, becoming barely visible or fades completely. Depending on its size, a single blood vessel may have to be injected several times, some weeks apart. For more information on spider veins, contact a cosmetic or plastic surgeon.