Weak or malfunctioning vein valves cause blood to pool and veins to protrude under the skin, appearing rope-like and causing discomfort. Spider veins are dilated capillaries under the skin's surface that are blue, red, or purple in color and have a web-like appearance. Factors that contribute to vein problems include heredity, pregnancy, birth control pills, lack of exercise, prolonged sitting/standing, obesity, and aging. Popular treatments for varicose and spider veins are sclerotherapy, foam sclerotherapy, endovenous laser, and microphlebectomy.