Anyone who suspects a blood clot in the leg should contact a doctor or go to the emergency room immediately, as recommended by the Agency for Healthcare Research and Quality. If a clot breaks free from its location in the leg, it can cause life-threatening complications.
If a clot forms in one of the veins in the leg, it can cause swelling, redness and discomfort at the affected site. A warm spot on the leg is another potential indicator of a blood clot, reports the AHRQ. Once a blood clot forms, it is possible for the clot to break loose and travel to the lungs. This condition, known as a pulmonary embolism, is very dangerous.