What causes varicose veins?
There are 2 types of varicose veins - primary (no obvious cause is known) or secondary (due to some underlying problem).
| Primary varicose veins
These are the more common sort. It is not clear if the first problem is leaky valves or weakness in the vein wall. The end result is flow of blood down the vein towards the ankle. This increases the pressure of blood in the veins causing the them to become longer and to dilate (balloon out) - this causes the varicose veins you can see. In time this pressure causes discolouration of the skin at the inner ankle. The skin may become thickened and weaker. Minor injuries and infection can lead to the formation of an ulcer.
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There are a number of theories about why varicose veins develop:
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They may be due to 'wear and tear' as they become commoner with age. |
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There seems to be a family history in many cases suggesting that we inherit a defect in these veins or valves which leads on to varicose veins. White races are more prone to varicose veins than coloured ones. |
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Some think they are due to jobs that involve standing for long periods - there is no strong evidence for this. |
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A weak link between varicose veins and obesity may exist in women but not in men. |
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There is no evidence that varicose veins are due to diet, tight clothes etc. |
Secondary varicose veins
This means that the vein have developed because of an underlying problem:
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This may be obstruction to venous return to the heart e.g. pregnancy, abdominal tumours (such as fibroids, ovarian cysts etc) or rare conditions such as retroperitoneal fibrosis where the veins in the pelvis and abdomen become encased in scar tissue. |
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If the deep veins in the leg are damaged because of deep vein thrombosis (blood clots) the superficial veins may become overloaded with blood leading to the formation of varicose veins. |
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There are also some rare congenital (we are born with them) conditions which may lead to the formation of varicose veins in odd distributions. These are usually apparent from a young age e.g. Klippel-Trenaunay syndrome. |
