Thrombophlebitis (phlebitis): treatment, symptoms, causes and when to worry

The NHS says treatment for phlebitis may not be needed if symptoms are mild, but may be recommended if symptoms are severe or do not go away. Treatments may include anti-inflammatory medicines (a cream or gel can be used if the area is small), compression stockings, which are only suitable for some people and should be recommended and fitted by a health professional, and blood-thinning medicine to reduce the risk of DVT or further blood clots and help stop phlebitis coming back.

Cambridge University Hospitals lists one or more of the following depending on symptoms: keeping active, a hot flannel over the vein, painkillers such as ibuprofen (not advised in pregnancy) or paracetamol, anti-inflammatory gel for mild disease affecting a small area, raising the leg so the foot is higher than the hip, and compression stockings if a leg vein is affected. Depending on the extent, you may be referred for medical assessment and a course of daily anticoagulant tablets to improve symptoms and reduce the risk of the clot extending and of DVT, or to a vascular clinic.

The NHS lists pain, tenderness or swelling in the affected area, warm and itchy skin, and changes to the colour and texture of the surrounding skin, which may be red, thick and hard. It can develop within hours or over a few days.

Cambridge adds swelling, redness and tenderness along a part of the vein, with a fever sometimes. If a clot forms inside the inflamed vein, it may feel hard or knobbly. When inflammation settles, a persistent darker area of skin (hyperpigmentation) and a small firm lump may remain and be tender for some time.

Cambridge explains that phlebitis means inflammation of a vein and thrombosis means a blood clot in a vein. If a vein becomes inflamed, a blood clot commonly forms inside, so thrombophlebitis is used to mean an inflamed vein with or without a clot.

Superficial veins lie just under the skin, often in the leg. Cambridge says it is different to, and much less serious than, deep vein thrombosis.

The NHS says it is not always clear what causes phlebitis. It is often linked to varicose veins, conditions that make the blood clot more easily such as thrombophilia, autoimmune conditions such as Behçet's disease, and having injections or a cannula put into a vein.

Other things the NHS says increase the chance are getting older, obesity, pregnancy, cancer, a previous episode, smoking and hormonal treatments such as HRT. Cambridge adds slowed blood flow (long flights, immobility or major surgery), the oral contraceptive pill, and says many cases occur for no apparent reason, with even a slight injury to the vein triggering it.

The NHS lists being pregnant among the things that increase the chance of phlebitis, and Cambridge says varicose veins, a typical site, are particularly common in pregnant women. Cambridge also says ibuprofen is not advised in pregnancy, so paracetamol, raising the leg and a warm flannel are used instead.

Tell your midwife or GP promptly about a painful, red, hard vein in pregnancy, because the risk of a DVT is higher in pregnancy and the leg should be assessed. Call 999 for chest pain or breathlessness.

The NHS says things you can do to ease phlebitis are to continue using the affected leg or arm, raise it while resting, put a warm, moist flannel over the area and take paracetamol or ibuprofen. If you have been prescribed blood-thinning medicine, do not take ibuprofen unless your doctor advises it.

Cambridge says most episodes last three to four weeks and that people with varicose veins are likely to have repeat episodes. Keep up your normal activity unless the pain is severe.

The NHS says to ask for an urgent GP appointment or get help from NHS 111 if you have throbbing or cramping pain in your leg, arm or neck, sudden swelling, warm skin around the painful area, red or darkened skin, or swollen veins that are hard or sore to touch, in case it is something more serious such as a DVT.

Cambridge says to see a doctor urgently if redness, inflammation or hardness spreads up the inner thigh towards the groin or is around the back of the knee or calf, the whole leg swells, pain becomes suddenly worse, or you develop new breathing problems or chest pain, as a clot can travel to the lung. Call 999 for chest pain or breathlessness. It also advises seeing a doctor if the vein becomes infected, with worsening pain, spreading redness and feeling generally unwell.

A clinician can usually diagnose it from your story and by examining the vein. If there is concern about the extent of the clot or DVT, an ultrasound scan of the veins can confirm the clot and show how far it extends, which affects whether blood-thinning treatment is offered. Cambridge says tests may be advised if there is no obvious explanation for recurring episodes, as for a small number of people it may be the first sign of a more serious condition.

Most cases are seen by a GP or minor injuries service, which can arrange an ultrasound if needed and refer on to a vascular or haematology clinic. Private vascular and vein clinics can treat the underlying varicose veins, which Cambridge says make repeat episodes likely; ask about the scan and the plan if a clot is extensive.