Varicose Veins and Deep Vein Thrombosis: Telling Leg Problems Apart
Leg veins cause two very different kinds of problem, and the distinction matters because one is usually a quality-of-life issue while the other can kill within hours.
The anatomy in brief
The leg has two venous systems. Superficial veins run just under the skin and are visible. Deep veins run between the muscles and carry most of the blood. Perforating veins connect the two, and one-way valves keep blood moving upward against gravity.
Varicose veins are a superficial system problem caused by failing valves. Deep vein thrombosis is a clot in the deep system.
Varicose veins
When valves in the superficial veins fail, blood refluxes downward and pools, stretching the vein walls.
Features:
- Visible, bulging, rope-like veins, usually blue or dark purple
- Aching, heaviness or throbbing, worse after prolonged standing and at the end of the day
- Relief on elevating the legs
- Itching over the vein
- Night cramps
- Ankle swelling that improves overnight
- In advanced disease, brown skin staining around the ankle, hardened skin, eczema, and venous ulcers just above the inner ankle
Risk factors include family history, prolonged standing occupations, pregnancy, obesity, age and previous DVT.
Treatment ranges from conservative to interventional: graduated compression stockings, regular walking and calf exercises, leg elevation, weight management, avoiding long static standing, and then endovenous laser or radiofrequency ablation, foam sclerotherapy, or surgery for symptomatic or complicated disease. Treatment of true complications is medical, not cosmetic.
Deep vein thrombosis
A clot forms in a deep vein, most often in the calf or thigh. This is an emergency because the clot can break off and lodge in the lungs as a pulmonary embolism.
Features:
- Swelling of one leg, usually the whole calf or the whole limb
- Pain or cramping, often starting in the calf
- Warmth over the affected area
- Redness or discoloration
- Tenderness along the deep vein line
- Visible surface veins becoming more prominent
- Often no visible varicosities at all
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The critical distinguishing feature is asymmetry with swelling and pain developing over hours to days, rather than a chronic ache in visibly varicose legs.
Pulmonary embolism signs, which demand emergency care: sudden breathlessness, sharp chest pain worse on breathing in, coughing blood, rapid heart rate, light-headedness or collapse.
Who develops DVT
- Immobility: long-haul travel, bed rest, plaster casts, hospital admission
- Recent surgery, especially orthopaedic, pelvic or abdominal
- Cancer and some cancer treatments
- Pregnancy and the postpartum period
- Oestrogen-containing contraception and hormone therapy
- Inherited clotting disorders
- Obesity
- Smoking
- Previous DVT
- Severe infection or dehydration
- Central venous catheters
How they are distinguished clinically
Assessment usually includes a Wells score, a D-dimer blood test, and a compression ultrasound of the leg veins, which is the definitive test. A negative D-dimer in a low-risk patient effectively excludes DVT; a raised D-dimer is not specific and needs imaging.
Treatment of DVT
Anticoagulation is started promptly, now usually with a direct oral anticoagulant, and continued for at least three months, longer if the cause was unprovoked or persists. Compression stockings help symptoms. Catheter-directed thrombolysis is used in selected extensive cases. Treating an underlying cause, including investigating for an occult cancer in some patients, is part of care.
Superficial thrombophlebitis
A third, intermediate entity: a clot in a superficial vein, producing a tender, firm, red cord just under the skin. It is usually less dangerous but can extend into the deep system, so extensive or thigh-level cases are assessed and sometimes anticoagulated.
Prevention during travel and immobility
- Walk every one to two hours on long journeys, or at minimum do calf pumps in your seat
- Stay hydrated and limit alcohol
- Wear graduated compression stockings on flights over four hours if you have risk factors
- Follow post-surgical anticoagulation and early mobilisation advice
- Discuss contraception choices with your doctor if you have a clotting history
When to seek same-day care
New one-sided leg swelling with pain, especially after travel, surgery, immobility or in pregnancy. Any breathlessness or chest pain with leg symptoms is an emergency.
This is general information. New leg swelling should be assessed by a doctor rather than monitored at home.