Thrombophlebitis is a blood clot (thrombus) inside an inflamed vein. It mainly affects the body's superficial veins — those that are seen easily near the surface of the skin, especially in the legs. Thrombophlebitis is very common in people who have varicose veins. However, it also can occur in people with medical conditions that lead to sluggish blood flow in the legs, especially pregnant women and people who are immobilized because of stroke or cancer. People who receive injections or medications intravenously (into a vein) also are more likely to get thrombophlebitis because their veins can become irritated by the tubes used or by the medication itself. Intravenous drug users are at high risk of a very serious type of thrombophlebitis that can develop into a vein infection.
Thrombophlebitis in a superficial leg vein is not the same as deep vein thrombosis. Deep vein thrombosis is a serious condition that is not treated with simple local therapy. It requires administration of anti-clotting drugs, usually heparin and warfarin (Coumadin).