What Are Varicose Veins?
Varicose veins usually announce themselves as bulging, bluish cords running just beneath the surface of your skin. They almost always affect legs and feet. Visible swollen and twisted veins -- sometimes surrounded by patches of flooded capillaries known as spider veins -- are considered superficial varicose veins. Although they can be painful and disfiguring, they are usually harmless. When inflamed, they become tender to the touch and can hinder circulation to the point of causing swollen ankles, itchy skin, and aching in the affected limb.
Besides a surface network of veins, your legs have an interior, or deep, venous network. On rare occasions, an interior leg vein becomes varicose. Such deep varicose veins are usually not visible, but they can cause swelling or aching throughout the leg and may be sites where blood clots can form.
Varicose veins are a relatively common condition, and for many people they are a family trait. Women are at least twice as likely as men to develop them. In the U.S. alone, they affect about 23% of all Americans.
What Causes Varicose Veins?
To help circulate oxygen-rich blood from the lungs to all parts of the body, your arteries have thick layers of muscle or elastic tissue. To push blood back to your heart, your veins rely mainly on surrounding muscles and a network of one-way valves. As blood flows through a vein, the cup-like valves alternately open to allow blood through, then close to prevent backflow.
In varicose veins, the valves do not work properly -- allowing blood to pool in the vein and making it difficult for the muscles to push the blood "uphill." Instead of flowing from one valve to the next, the blood continues to pool in the vein, increasing venous pressure and the likelihood of congestion while causing the vein to bulge and twist. Because superficial veins have less muscle support than deep veins, they are more likely to become varicose.
Any condition that puts excessive pressure on the legs or abdomen can lead to varicose veins. The most common pressure inducers are pregnancy, obesity, and standing for long periods. Chronic constipation and -- in rare cases, tumors -- also can cause varicose veins. Being sedentary also may contribute to varicosity, because muscles that are out of condition offer poor blood-pumping action.
The likelihood of varicosity also increases as veins weaken with age. A previous leg injury may damage the valves in a vein which can result in a varicosity. Genetics also plays a role, so if other family members have varicose veins there is a greater chance you will, too. Contrary to popular belief, sitting with crossed legs will not cause varicose veins, although it can aggravate an existing condition.