Varicose veins | Cleveland Clinic
Varicose veins

What are veins?

Veins are blood vessels that carry blood from your body's tissues to your heart. The heart pumps blood to your lungs to pick up oxygen. The oxygen-rich blood flows through tiny blood vessels called capillaries, where it gives up its oxygen to the body's tissues. Your blood then returns to your heart through your veins.

Veins have one-way valves that help keep blood flowing toward your heart. If your valves are weak or damaged, blood can back up and pool in your veins. This causes the veins to swell leading to varicose veins.

Varicose veins | Cleveland Clinic

What are varicose veins?

Varicose veins are abnormal, swollen blood vessels caused by a weakening of the vessel wall. They might appear as clusters of blue or purple veins. They are sometimes surrounded by thin red capillaries known as spider veins (a group of small blood vessels located close to the surface of the skin).

Varicose and spider veins can appear anywhere, but they often appear on the legs and in the pelvic area. Most varicose veins develop near the surface of the skin. Deeper varicose veins cannot be seen, but may cause the skin above them to swell, become darker, or harden.

What causes varicose veins?

When the blood vessel walls weaken, veins swell causing blood to back up and pool inside the vein. Normally, blood flows through the vein in one direction toward the heart. Varicose veins become a new route for blood to flow.

What are the symptoms of varicose veins?

Symptoms usually appear before the age of 40 and might include:

  • Swollen, twisted clusters of purple or blue veins
  • Swollen legs, ankles, and feet
  • Muscle cramps, throbbing, soreness, or aching in the legs
  • Legs that feel "heavy"
  • Soreness behind the knee
  • Itching around the vein
  • Leg muscles that tire easily
  • Brown discoloration of the skin
  • Skin ulcers

Last reviewed by a Cleveland Clinic medical professional on 07/15/2019.


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