Deep vein thrombosis (DVT) is a condition in which a blood clot forms in one of your deep veins, usually in your leg. DVT can cause pain and swelling and may lead to complications, such as pulmonary embolism.

Swollen legs due to deep vein thrombosis are a fairly common presentation. These are effectively treated by compression stockings and compression therapy. A rare but serious complication of DVT is dislodgment of the clots from the legs to the lungs.