Deep vein thrombosis (DVT) is a serious condition that occurs when a blood clot forms in a vein located deep inside your body. A blood clot is a clump of blood that’s turned to a solid state. Deep vein blood clots typically form in your thigh or lower leg, but they will also develop in other areas of your body. Other names related to this condition may include thromboembolism, post-thrombotic syndrome, and postphlebitic syndrome. Common symptoms include: swelling in your foot, ankle, or leg, usually on one side, cramping pain in your affected leg that sometimes begins in your calf, severe, unexplained pain in your foot and ankle, an area of skin that feels warmer than the skin on the encompassing areas and skin over the affected area turning pale or a reddish or bluish color.