Expert guide by Mr Stephen Blair, Consultant Vascular Surgeon

What Are
Varicose Veins?

Varicose veins affect approximately 30% of adults. Understanding what causes them, how to recognise the symptoms, and when to seek treatment is the first step towards resolving them.

1

How do they develop?

Valve failure mechanics explained

2

Causes & risk factors

Genetics, pregnancy, lifestyle
3

Symptoms to look for

Aching, swelling, skin changes
4

Types of varicose veins

GSV, SSV, thread veins, reticular
5

Are they dangerous?

Complications & when to treat

How do varicose veins develop?

The veins in your legs have a demanding job — they must return blood from the feet and legs back to the heart against gravity. To prevent blood from flowing backwards, the veins contain a series of one-way valves that open to allow blood to pass upwards and close to prevent it falling back down.

When these valves weaken or fail, blood pools in the vein below the faulty valve. This increased pressure causes the vein to enlarge, stretch, and become tortuous — the characteristic appearance of varicose veins. Over time, the pressure on adjacent veins increases, causing further valves to fail and additional varicose veins to develop.

The condition is therefore progressive: untreated varicose veins tend to worsen over time, and the risk of complications — including skin changes, swelling, and leg ulcers — increases the longer treatment is deferred.

Why early treatment matters

The NHS no longer routinely treats varicose veins for the majority of patients. Early private treatment — before complications develop — is always more straightforward and leads to better outcomes. A free Colour Duplex Ultrasound Scan at your initial consultation confirms whether your veins require treatment.

What causes varicose veins?

Varicose veins develop when the valves inside the veins fail — but several factors significantly increase the likelihood of this happening.

Genetics

Varicose veins run strongly in families. If one or both parents are affected, your risk is significantly increased.

Age

Prevalence increases with age as vein walls and valves naturally weaken. More common in adults over 50.

Pregnancy

Increased blood volume and hormonal changes dilate vein walls. The growing uterus also increases pelvic vein pressure.

Prolonged standing

Occupations requiring long periods of standing significantly increase the pressure within the leg veins.

Obesity

Excess weight increases pressure on the veins of the lower limbs, accelerating valve failure.

Previous DVT

Deep vein thrombosis can permanently damage venous valves, leading to secondary varicose veins.

What are the symptoms of varicose veins?

Not all varicose veins cause symptoms beyond their visible appearance. However, significant varicose veins commonly cause one or more of the following:

Aching or heaviness in the legs — worse after prolonged standing

Swelling of the ankle and lower leg — most noticeable in warm weather

Itching or burning over the veins, particularly around the ankle

Muscle cramps, particularly at night

Skin changes around the ankle — discolouration, thickening, or scaling

Restless legs — an urge to move the legs, often worse at night

Visible bulging, twisted veins beneath the skin surface

Throbbing or a feeling of tension in the legs

Symptoms that require prompt assessment

If you develop sudden redness, hardness, or pain along a varicose vein (superficial thrombophlebitis), or if a varicose vein bleeds, you should seek medical attention promptly. Both are complications that are more likely when varicose veins have been left untreated for a long time.

Types of varicose veins

Varicose veins vary significantly in their size, location, and underlying cause. The treatment recommended by Mr Blair depends on which type — or combination of types — is present in your specific anatomy.

Great Saphenous Vein (GSV)

Runs from the foot along the inner thigh to the groin. When the valve at the top fails, blood refluxes the entire length of the vein, causing significant varicose veins along the inner thigh and calf. The most common type.

Treated with ClariVein

Small Saphenous Vein (SSV)

Runs from the foot up the back of the calf to the back of the knee. When its valves fail, varicose veins develop at the back of the lower leg. ClariVein ablation is equally effective for SSV reflux.

Treated with ClariVein

Reticular Veins

Smaller, bluish-green veins visible beneath the skin — larger than thread veins but smaller than varicose veins. Often feed into thread veins. Can cause discomfort and cosmetic concern.

Treated with foam sclerotherapy

Thread Veins & Spider Veins

Very small dilated capillaries visible just beneath the skin surface. Appear as fine red, purple, or blue lines in web-like patterns on the thighs, knees, calves, and face. Not the same as varicose veins.

Treated with microsclerotherapy

Are varicose veins dangerous?

Not always — but they can be. The risk depends on the size and severity of the varicose veins, how long they have been present, and whether early complications are developing. Minor varicose veins may remain stable. However, significant varicose veins — particularly those causing symptoms — carry a real risk of complications over time.

Moderate risk

Varicose Eczema

Redness, itching, scaling, and skin thickening around the ankle. A direct consequence of raised venous pressure — often the first visible sign of skin damage.

Moderate risk

Superficial Thrombophlebitis

Blood clot formation within varicose veins, causing pain, redness, and hardness. Can occasionally extend into the deep system and cause DVT.

Significant risk

Chronic Venous Insufficiency

Persistent swelling of the ankle and lower leg, progressive skin discolouration, and skin changes that become increasingly difficult to treat over time.

Significant risk

Lipodermatosclerosis

Chronic inflammation and hardening of the skin and subcutaneous fat around the ankle — a precursor to leg ulceration. Very difficult to reverse once established.

Serious risk

Venous Leg Ulcers

Open wounds most commonly around the ankle. Affect approximately 1% of the UK population. The most common cause of leg ulceration. The majority can be prevented by treating varicose veins before skin changes develop.

Serious risk

Bleeding

Enlarged varicose veins close to the skin surface can bleed spontaneously or after minor injury. More common in elderly patients with fragile overlying skin. Can be alarming and significant.

When should I seek treatment?

You should seek an assessment with a vascular specialist if any of the following apply to you:

Aching or heaviness

Particularly at end of day or after prolonged standing

Ankle or leg swelling

Especially if new or worsening

Skin changes around the ankle

Discolouration, itching, thickening, or scaling

Previous thrombophlebitis

Blood clots in superficial varicose veins

Visually prominent veins

Causing distress or affecting quality of life

Family history

Of varicose veins or venous leg ulcers

The NHS no longer routinely treats varicose veins

The majority of patients with varicose veins — even significant and symptomatic ones — are no longer eligible for NHS treatment. The NHS now only treats patients with serious complications such as bleeding, active leg ulcers, or significant skin changes. For most patients, private treatment is the most reliable route to resolution. Early treatment is always more straightforward and leads to better outcomes.

A free Colour Duplex Ultrasound Scan at your initial consultation at Liverpool Varicose Veins Clinic will confirm whether the underlying venous valves are failing and whether treatment is advisable — with no obligation to proceed.