A skin ulcer is caused by a venous reflux disorder or chronic leg venous hypertension that is not treated. Venous stasis ulcer or sores are areas of the lower leg where the skin has opened and exposed the flesh beneath. Early signs that a venous stasis ulcer may develop include darkening of the skin in the area of the ankle. Gradually, the skin may become leathery or waxy in appearance. Without treatment of the venous disease, the skin may breakdown and bleeding may occur. Ulcers can differ in size or appearance. They are painful, odorous open wounds which weep fluid and can last for months or even years. Most leg ulcers occur when vein disease is left untreated. They are most common among older people but can also affect individuals as young as 18.