Varicose veins are veins under the skin of the legs which have become widened, bulging and tortuous. They are very common and do not cause medical problems in most people. Blood flows down the legs through the arteries and back up the legs through the veins. There are two main systems of veins in the legs - the deep veins, veins deep inside the muscles, which are not visible and which carry most of the blood back up the legs to the heart, and the veins under the skin, which are less important and which can form varicose veins. All these veins contain valves which should only allow the blood to flow upwards (see diagram). If the veins become widened and varicose these valves no longer work properly.
Blood can then flow backwards down the veins and produce a head of pressure when standing, walking about or sitting. Lying down or "putting your foot up" relieves this head of pressure and usually makes the legs feel better. Both symptoms and treatment depend on how badly the valves in the veins are working, although the trouble people get from their varicose veins is very variable. In women varicose veins often appear first in pregnancy when hormones relax the walls of the veins and when the womb presses on the veins coming up from the legs. People who are overweight are more likely to get varicose veins and to find symptoms from them troublesome.
There is some tendency for bad varicose veins to run in families, but this is by no means always the case. Usually there is no special cause for varicose veins.
Very many people have no symptoms at all from their varicose veins, except for the fact that they are noticeable and their appearance can be embarrassing. Other than cosmetic embarrassment the commonest symptoms from varicose veins are aching, discomfort and heaviness of the legs, which are usually worse at the end of the day. Sometimes the ankle can swell, too. These symptoms are not medically serious, but can be treated if they are sufficiently troublesome. Although varicose veins can get worse over the years, this often happens very slowly.
In a few people the high pressure in the veins causes damage to the skin near the ankle, which can become brown in colour, sometimes with scarred white areas. Eczema (a red skin rash) can develop. Other problems which varicose veins can occasionally produce are phlebitis and bleeding. Phlebitis (sometimes called thrombophlebitis) means inflammation of the veins and is often accompanied by some thrombosis (clotting of blood) inside the affected veins, which become hard and tender. This is not the same as deep vein thrombosis and is not usually dangerous. It does not mean that the varicose veins necessarily have to be treated.