Superficial thrombophlebitis signs and symptoms include:

• Warmth, tenderness and pain in the affected area
• Redness and swelling

Deep vein thrombosis signs and symptoms include:

• Pain
• Swelling

When a vein close to the surface of your skin is affected, you might see a red, hard cord just under the surface of your skin that's tender to the touch. When a deep vein in the leg is affected, your leg may become swollen, tender and painful.

The cause of thrombophlebitis is a blood clot, which can form in your blood as a result of:

• An injury to a vein
• An inherited blood-clotting disorder
• Being immobile for long periods, such as during an injury or a hospital stay

Your risk of thrombophlebitis increases if you:

• Are inactive for a prolonged period, either because you're confined to bed or are traveling in a car or plane for a long period
• Have varicose veins, which are a common cause of superficial thrombophlebitis
• Have a pacemaker or have a thin, flexible tube (catheter) in a central vein, for treatment of a medical condition, which may irritate the blood vessel wall and decrease blood flow
• Are pregnant or have just given birth
• Use birth control pills or hormone replacement therapy, which can make your blood more likely to clot
• Have a family history of a blood-clotting disorder or a tendency to form blood clots
• Have had previous episodes of thrombophlebitis
• Have had a stroke
• Are older than 60
• Are overweight or obese
• Have cancer
• Smoke

Complications from superficial thrombophlebitis are rare. However, if you develop DVT, the risk of serious complications increases. Complications might include:

• Pulmonary embolism. If part of a deep vein clot becomes dislodged, it can travel to your lungs, where it can block an artery (embolism) and become potentially life-threatening.
• Post-phlebetic syndrome. This condition, also known as post-thrombotic syndrome, can develop months or even years after you've had DVT. Post-phlebetic syndrome can cause lasting and possibly disabling pain, swelling and a feeling of heaviness in the affected leg.