Without proper treatment, varicose veins can appear. They can cause complications such as ulcers or wounds due to blood pooling in the veins of the lower legs. Spontaneously or due to light trauma, the varicose vein can break causing hemorrhaging. In addition, a varicose vein can cause a venous infection, a blood clot which blocks the protruding veins and obstructs the venous blood flow. In severe cases, a blood clot can block the deep veins (deep vein thrombosis), which is a very serious condition because the blood clot can move through the bloodstream toward the heart causing pulmonary embolism with life-threatening consequences.