Thrombophlebitis is inflammation in a vein in an area where a blood clot has formed. Often the term thrombophlebitis is shortened to "phlebitis."

There are two types of phlebitis.

• Superficial phlebitis occurs when a blood clot and inflammation develop in a small vein near the surface of the skin. This type of phlebitis rarely causes a serious problem.
• Deep vein thrombosis occurs when a blood clot and inflammation are deep inside a vein in a leg, the lower abdomen (pelvis), or, rarely, the arm. It requires tests and treatment by a doctor.