Understanding Varicose Veins: The Basics

What Are Varicose Veins?

Varicose veins are bulging, sometimes bluish veins that look like cords running just beneath the surface of your skin. They usually affect the legs, ankles, and feet.

Varicose veins that are visibly swollen, twisted, and sometimes surrounded by patches of flooded capillaries (or small blood vessels) known as spider veins are considered superficial varicose veins. They may cause swollen ankles, itchy skin, and aching in the affected area. Superficial varicose veins can be painful but are usually harmless.

Along with veins that run along the surface of your skin, your legs have interior, or deep, veins. Sometimes, an interior leg vein becomes varicose (abnormally swollen or enlarged). Such deep varicose veins are usually not visible, but they can cause swelling or aching throughout the leg and may serve as sites where blood clots can form.

Varicose veins are a relatively common condition. 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 up to 35% of people.

Spider veins vs. varicose veins

Spider veins are smaller than varicose veins and don’t bulge out. They look like spider webs or tree branches, and they are red, blue, or purple. Unlike varicose veins, spider veins may also appear on your face.

Both varicose and spider veins are damaged blood vessels, but spider veins are not actually veins — they are capillaries, venules, and arterioles, which are smaller blood vessels. Spider veins rarely cause pain or other symptoms beyond their appearance.

Varicose Veins Causes

To help move 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 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 pressure in the veins and the odds of buildup, causing the vein to bulge and twist. Because superficial veins have less muscle support than deep veins, they are more likely to become varicose.