Varicose veins are unsightly stretched veins that protrude through the skin, particularly in the legs. They can occur anywhere from the groin to the feet, but commonly present with bulging in the calf.
Veins are the tubes that carry blood from the body back to the heart. In the legs these tubes have to carry blood upwards against gravity, and so veins contain unidirectional valves to keep the blood flowing upwards. Varicose veins develop when one or more of these valves gives way (often in the groin or behind the knee), and blood starts to flow back down the leg. This increased back pressure on the veins and their branches eventually causes many of them to stretch, lengthen and bulge out, a condition we call varicose veins.
Varicose veins are rarely painful, but may cause increasing discomfort as they enlarge. Frequently the legs will ache, particularly after standing, in hot weather or before a woman's periods. As they progress, itchiness, increased cramping and swelling of the ankles may ensue. Eventually, broken veins (thread veins, spider veins) develop. Skin colour may darken - particularly around the ankle - and in advanced cases complications such as phlebitis, thrombosis or ulceration can occur.
Varicose veins may rarely be congenital (developing from or soon after birth) but more often develop gradually through life. Heredity is the single most important factor in most cases, although pregnancy plays an important part for women who develop varicose veins. They may also develop after trauma or deep vein thrombosis. As with thread veins they occur more frequently in women, and tend to get worse with age.