Health A-Z

Medical Content Created by the Faculty of the
Harvard Medical School

Varicose Veins

What Is It?

Varicose veins occur when veins just below the skin's surface are damaged, become swollen and fill with too much blood.

Veins are the blood vessels that return blood to the heart. Arteries carry blood away from the heart to the rest of the body,

Varicose veins most commonly occur in the legs. In about 50% of cases, the condition runs in families, and probably is related to an inherited weakness in the veins' walls or the valves inside veins that keep blood from backing up. In other cases, changes in blood pressure related to pregnancy or obesity may make it harder for blood to flow back to the heart, increasing the tendency for blood to pool in the veins. Also, occupations that require uninterrupted standing (waitresses and waiters, nurses, mothers with young children) may force leg veins and valves to work against gravity for hours, increasing the risk of pressure-related vein and valve damage. Garters and knee-high socks also can increase the risk of varicose veins if their tight elastics slow blood flow in the legs.

About 15% of adults in the United States have varicose veins, and the condition is 2 to 3 times more common in women than men. Although varicose veins most often are seen in the legs, they also can occur in the vagina during pregnancy or around the anus as hemorrhoids.

Varicose veins can be associated with prior blood clots and damage to the deeper veins in one or both legs, a situation that sometimes can lead to chronic venous insufficiency. When this happens, the veins lose their ability to effectively move blood back to the heart. This can cause significant leg swelling and skin sores or ulcers.