Can varicose veins cause lymphoedema?

If your legs are swollen, it's natural to wonder what's the cause of this.

Many people assume swelling occurs due to having varicose veins. Others worry they may have lymphoedema after reading about it online.

The truth is that both conditions can cause swollen legs, but they're not the same thing. They have different causes, different treatments and, in many cases, different long-term outlooks.

They can also occur together.

Understanding the difference is important because treating the wrong condition may do little to improve your symptoms.

Swollen legs don't always have one simple explanation

Leg swelling is one of the most common reasons patients seek advice from a vascular specialist.

Sometimes the cause is obvious.

Sometimes it isn't.

Swelling can be caused by varicose veins, chronic venous insufficiency, lymphoedema, heart disease, kidney disease, certain medications or simply spending long periods standing or sitting.

That's why we don't assume every swollen leg has the same explanation.

Can varicose veins cause swelling?

Varicose veins are one of the most common causes of chronic leg swelling.

Healthy veins carry blood back towards the heart with the help of tiny one-way valves.

When those valves stop working properly, blood does not flow efficiently back towards the heart. This is known as venous reflux.

Over time, this leads to congestion in the veins, and fluid collects in the surrounding tissues, causing swelling, particularly around the ankles and lower legs.

Many people notice that the swelling:

• gets worse as the day goes on
• improves overnight
• becomes more noticeable after long periods of standing
• is accompanied by aching or heaviness

Left untreated, chronic venous insufficiency can also lead to skin changes, inflammation and venous leg ulcers.

What is lymphoedema?

Lymphoedema is a different condition.

This does not primarily affect the veins, rather being due to abnormalities in the lymphatic system. The lymphatic system consists of tiny tubules called lymphatics, which remove excess fluid from the body's tissues.

If the lymphatic system isn't working properly, fluid builds up in the tissues, causing persistent swelling.

Unlike swelling caused by venous disease, lymphoedema often doesn't usually significantly improve simply by putting your feet up overnight.

The swelling may gradually become firmer over time and the skin can begin to feel thicker.

Can varicose veins lead to lymphoedema?

Yes, although it's less common than many people realise.

When chronic venous insufficiency has been present for many years, the constant build-up of fluid places extra strain on the lymphatic system.

Eventually, the lymphatic vessels may no longer be able to keep up with the amount of fluid that needs to be drained.

This is sometimes referred to as phlebolymphoedema, where both the veins and the lymphatic system contribute to the swelling.

How can you tell the difference?

There isn't always a clear answer without an assessment.

However, there are some clues.

Swelling caused by venous disease often:

• starts around the ankles
• becomes worse throughout the day
• improves after elevating the legs
• occurs alongside visible varicose veins
• is associated with aching or heaviness

Lymphoedema is more likely to:

• persist throughout the day and night
• involve the foot as well as the ankle
• gradually become firmer over time
• cause skin thickening in more advanced cases

Some patients have features of both conditions.

That's why diagnosis shouldn't rely on symptoms alone.

How do vascular surgeons investigate swollen legs?

The first step is always understanding your symptoms.

We'll ask when the swelling began, whether it affects one or both legs, whether it changes during the day and whether you've experienced previous blood clots, surgery or cancer treatment.

We'll also examine your legs for signs of venous disease, skin changes and lymphoedema.

If we suspect an underlying vein problem, we'll perform a duplex ultrasound scan.

This allows us to see how blood is flowing through the veins and identify venous reflux.

If the swelling appears more consistent with lymphoedema or another medical condition, we may recommend further assessment or refer you to the appropriate specialist.

Can treating varicose veins reduce swelling?

In many cases, yes.

If venous reflux is responsible for the swelling, treating the underlying vein problem often improves symptoms significantly.

Many patients notice that their legs feel lighter, less swollen and more comfortable after treatment.

However, if lymphoedema is also present, treating the veins may only address part of the problem.

That's another reason why making the correct diagnosis is so important before deciding on treatment.

Should you worry about swollen legs?

Not every swollen leg is a cause for concern.

However, persistent swelling should never simply be dismissed as part of getting older.

It's worth seeking medical advice if the swelling:

• keeps returning
• affects only one leg
• becomes painful
• is associated with skin discolouration
• causes the skin to become hard or thickened
• is accompanied by a leg ulcer
• develops suddenly without an obvious explanation

Early assessment can often identify the cause before more serious complications develop.

The bottom line

Varicose veins can cause swollen legs, and in some people longstanding venous disease can eventually affect the lymphatic system as well.

The difficulty is that swollen legs don't always have a single cause.

What appears to be lymphoedema may actually be venous disease. Equally, someone with varicose veins may have swelling that's caused by something else entirely.

The only reliable way to understand why your legs are swollen is through a proper assessment.

By identifying the underlying cause, your vascular specialist can recommend the treatment that's most likely to improve your symptoms rather than simply managing them.