Veins carry de-oxygenated (oxygen poor) blood from the body towards the heart. This backflow of the oxygen poor blood is ensured by normal function of the veins, their walls and their valves. Varicose veins have weakened walls and valves causing them to dilate and become twisted. This can be seen especially with the superficial veins close to the skin. The abnormal valves combined with gravity causes pooling of the blood that gives rise to the swelling (dilating) of the veins.
This abnormal functioning can result because of genetic predisposition (runs in the family), overweight, hormonal changes, pregnancy, long periods of standing (occupation related) and other medical diseases may also aggravate this condition.
Varicose veins can lead to venous thrombosis (blood clots) that will further affect the circulation. The poor circulation leads to swollen and painful ankles, feet and legs; skin changes on the lower legs (darkening, scaling, itchiness, skin temperature changes) and even ulcers on the lower legs. This condition is called venous stasis. Blood clots in the legs can be very serious and symptoms include swelling, redness and pain especially around the affected vein.
Varicose veins become more bluish with time due to the blood pooling in the veins. Spider veins are the very fine veins surrounding the larger veins.
It is important to treat varicose veins to prevent blood clotting, improve deeper vein circulation and improve other problems such as leg pains, swelling and skin changes.