Varicose veins occur when the one-way valves in the veins in the leg fail, allowing blood under pressure to flow the wrong way. The veins are not designed to cope with this increased pressure, so they enlarge and become prominent and more visible.

Venous disease is largely inherited. It affects men and women equally but starts earlier in women, often beginning in pregnancy. Causes include obesity, high blood pressure and smoking. Making lifestyle changes that reduce weight and blood pressure, and quitting smoking can inhibit the progression of venous disease. Though not a cause of varicose veins, standing for long periods may exacerbate symptoms.

Injections to close off the veins (sclerotherapy) have a long proven record of success with spider veins, as well as veins less than 3-4 mm in diameter. However, for veins larger than 4 mm, sclerotherapy has provided only mixed results.

Ultrasound guided compression sclerotherapy can allow easier visualization when treating some veins. It is performed as an out-patient procedure, which means patients are able to avoid the inconvenience, discomfort and expense of an admission to hospital. Patients are usually able to drive home and return to normal activities immediately after the procedure.