Please note, I am not a doctor and I am not qualified to make medical claims or diagnose diseases. If you have any questions, please consult a doctor. Also, my views are my own, so it is not appropriate to post any opinions.
Varicose veins are caused by an enlarged blood vessel and a shortage of oxygen. They are common in children who suffer from a heart condition called hypertrophic cardiomyopathy. The arteries in the legs become smaller, so the blood pressure is higher and more difficult to control. As a result, the heart muscle's function can suffer, which causes pain in the legs. If the veins are not removed, the pressure inside the heart will increase, causing the heart to be more prone to sudden death.
A varicose vein can cause the leg to become numb. Varicose veins are usually found at the top of the leg, where the blood vessels pass down to the muscle, so it can often be seen by a doctor without having to touch the skin. A medical doctor is required to look at a leg and measure the thickness of the veins to make sure that they are clean. He also has to cut the veins with a scalpel.