Varicose veins are very common. They are usually a result of the valves not working properly and blood can flow back down the vein instead of towards the heart. This is called 'venous reflux'. This causes the vein to enlarge and can cause symptoms of ache or itching. More seriously, venous reflux can cause skin changes such as brown pigmenatation and varicose eczema. At this stage, if left untreated, there is an increased risk of leg ulcers.