Varicose veins and ulcers. View of varicose veins around the ankle & foot, with ulceration on the middle toes. Varicose veins are enlarged, tortuous or twisted superficial veins often found in the legs. They are caused by defective valves in the veins. In this case, the veins are distended & swollen due to blood collecting in the legs. Varicose veins are caused by an inherited tendency or obstruction of the veins. Ulcers are formed due to the poor blood and oxygen supply and nutrient starvation. The skin becomes dry, scaly, thin and hard. Treatment includes elastic support and sometimes surgery.