Varicose veins may become inflamed or infected, resulting in exquisitely tender legs that need treatment with antibiotics and anti-inflammatory drugs. Or the stagnant blood in them may clot, with the clot perhaps spreading to the bigger veins deep inside the leg. This condition can be life-threatening.
Or veins may get damaged in a trivial injury that would normally just result in a small cut, but because there is a possibly centimetre-wide blood vessel just below the surface, it can bleed impressively and dangerously, unless someone takes the simple first-aid measures of elevating the leg and pressing firmly over the cut.
When the condition is long-standing, it is often a sign of a condition known as chronic venous insufficiency. Because the pressure in veins is relatively low compared with that in arteries, and because the legs are such a long way from the heart when we walk upright rather than on all fours like other animals, getting blood back out of the legs once it has got there is a problem. (That same problem can cause similar dilated veins a bit higher up the body - haemorrhoids.)
The return of the blood relies on a system of one-way valves in the veins, and on the veins being squashed by activity in the muscles around them. If those valves stop working (as they may do when the veins become dilated), blood pools in the legs, and the supply of fresh blood to the area is compromised. Varicose eczema and other changes in the skin may be lead to ulceration, which can take months to sort out and may even require skin grafts.
Varicose veins are often blamed for other symptoms, too, and such symptoms, along with the presence of the veins, is usually enough for surgery to be offered to the patient. Problems are said to include "heaviness or tension", aching, cramps, itching and tingling. But a team from Edinburgh University reports in the British Medical Journal that such symptoms are in fact rarely due to varicose veins.
The researchers studied 1,500 people, and asked them about these feelings in their legs. The commonest complaints were "aching" in women (53.8 per cent) and "cramps" in men (34 per cent). Overall, women reported more problems than men, and all symptoms became more prevalent with age. Then the volunteers were examined by doctors to look for evidence of any varicose veins, and grade their severity. Of the entire group (adjusted for age) about 35 per cent had varicose veins (in contrast to symptoms, the figure is slightly higher in men than in women). But there was precious little evidence to link the presence of the veins with the symptoms attributed to them.
In the men, the only symptom that bore any relationship to varicose veins was itching. In women, heaviness, aching and itching correlated significantly with the presence of varicose veins, although the paper's authors say that even this finding "may be of limited clinical value".
They conclude that even in the presence of varicose veins, "most lower limb symptoms probably have a non-venous cause". They also say that many people with quite severe varicose veins have no symptoms at all. Nor is there any evidence to suggest that operating on varicose veins early (by which is meant, before the first skin changes of venous insufficiency appear) has any preventive effect on the later development of leg ulcers.
More then 50,000 varicose vein operations are carried out each year on the NHS. It is not major surgery, but even so, each operation costs about pounds 2,000 to carry out. In the ever-cost-conscious health service, we need to be sure that this is being spent wisely. Given the at best tenuous link between varicose veins and symptoms, the question arises whether operations are being performed unnecessarily.
Most patients seek surgery for uncomplicated varicose veins simply because they don't like the look of them, which is an entirely understandable reaction. But since this comes under the heading of "cosmetic" surgery, they may feel that they should also have other complaints, in order to persuade a surgeon to operate. At present it seems that many surgeons are happy to accept this as a reason to do so.
The researchers in Edinburgh advise that before considering surgery, a trial of "support hosiery" should be used, to see whether it has any effect on the patient's symptoms. Graded support stockings, properly fitted and properly worn, compress the dilated veins and force blood into the deeper veins inside the leg, which are more efficient at getting blood back up the body.
But even if symptoms do improve, it seems that at present the only way of finding out whether surgery will indeed help in the long term is to "operate and see". Although you'll almost certainly rid yourself of the squiggly blue lines running down your calves, you may also be left with your tingling, swollen, itchy legs as before. Which will leave your doctors scratching their heads as to what to do next.