Phlebitis (superficial thrombophlebitis)

Phlebitis literally means 'inflammation of a vein'.

The vein becomes inflamed because there is blood clotting inside it or the vein walls are damaged.

Superficial thrombophlebitis is the term for an inflamed vein near the surface of the skin (usually a varicose vein) caused by a blood clot.

What are the symptoms?

Superficial thrombophlebitis results in painful, hard lumps underneath the skin and redness of the overlying skin.

This is usually on the lower leg, although it can occasionally affect surface veins in the arms, penis or breast.

Is it serious?

Superficial thrombophlebitis is typically more annoying than serious. 

Usually, the blood clot clears and the inflammation dies down within a few weeks.

Most people with superficial thrombophlebitis are otherwise well. There shouldn't be any foul discharge or abscess, and it's normally just lumps under the skin rather than swelling of the whole calf.

This may be painful, but it shouldn't prevent you walking reasonably well.

Who's most at risk?

You're more at risk of superficial thrombophlebitis if you:

• have varicose veins
• smoke
• are very overweight
• take the contraceptive pill or HRT (although these only slightly increase your risk of blood clots)
• are pregnant
• have had a previous blood clot or other problem with the vein
• have recently had injections or a drip put into the vein
• have a condition that causes the blood to clot more easily, such as thrombophilia, polyarteritis (inflammation of the smaller arteries) or polycythaemia (a high concentration of red blood cells in your blood)
• have cancer

How is it treated?

Phlebitis is inflammation, not infection, so antibiotics aren't helpful.

You can follow this advice to help reduce any pain and swelling:

• raise the leg to help reduce swelling
• ask your doctor if compression stockings would be suitable for you to help reduce swelling
• keep active to keep the blood circulating
• press a cold flannel over the vein to ease any pain
• take anti-inflammatory painkillers (aspirin is best) to ease any pain
• rub an anti-inflammatory cream or gel on the area if the affected area is only small

What's the outlook?

When the inflammation settles, you may be left with darkened skin and the lump may take 3 or 4 months to go. But most people make a full recovery.

If the thrombophlebitis occurred in a varicose vein, it's likely that the varicose veins will keep coming back, possibly with further episodes of thrombophlebitis. 

This is because there's a basic problem with the vein, and you may need this removing. 

Read about the treatment of varicose veins.

Risk of deep vein thrombosis

There's a small chance of the blood clot travelling along the vein to where it meets a deeper vein, and a deep vein thrombosis (DVT) developing.

This is more likely if the surface clot extends into the upper thigh or groin, or behind the knee (in places where superficial veins meet deeper veins).

It's also more likely to occur if the affected vein is a normal vein rather than a varicose vein, if you've had a DVT before, or if you're immobile.

A DVT can cause pain, swelling and a heavy ache in your leg – see your GP immediately if you experience these symptoms.

Read more about DVTs.