Varicose veins are enlarged, twisted veins that appear as bluish or dark purple cords beneath the surface of the skin, most commonly on the legs and calves. They develop when the one-way valves inside leg veins weaken or become damaged, allowing blood to flow backward and pool rather than being carried efficiently back up to the heart.
Varicose veins are extremely common and, for most people, are primarily a cosmetic concern rather than a dangerous one. However, they can also cause genuine discomfort, and in a smaller number of cases can signal or progress toward more significant venous problems. Understanding how the venous system works, what causes it to fail, and what options exist for managing symptoms allows most people to make confident, informed decisions about their vein health.
Understanding How Leg Veins Works
Unlike arteries, which rely on the pumping force of the heart to push blood outward, veins in the legs must move blood back up against gravity. This is made possible by two mechanisms working together: a series of one-way valves within the veins that prevent blood from flowing backward, and the "calf muscle pump" — the act of walking and contracting the calf muscles, which squeezes the deep veins and helps propel blood upward with each step.
When these valves become weakened, stretched, or damaged, they no longer close properly. Blood that should be moving upward instead flows backward and pools in the lower sections of the vein, a condition known as venous reflux. Over time, this pooling raises pressure within the vein, causing it to stretch, bulge, and take on the twisted, rope-like appearance characteristic of varicose veins.
Types of Vein Conditions
Varicose veins exist on a spectrum of venous conditions, which are sometimes confused with one another
- Varicose Veins: Large, bulging, rope-like veins visible beneath the skin, usually dark purple or blue, most often affecting the legs. They occur when valve failure allows significant backward blood flow and pooling.
- Spider Veins (Telangiectasia): Smaller, thinner, web-like clusters of red, blue, or purple veins that lie closer to the skin's surface. They are generally a cosmetic concern and rarely cause the aching or heaviness associated with true varicose veins.
- Reticular Veins: Slightly larger than spider veins but smaller than varicose veins, appearing as a flat, bluish-green network under the skin. They often act as "feeder" veins that supply spider veins.
- Chronic Venous Insufficiency (CVI): A more advanced, ongoing condition in which the leg veins are persistently unable to return blood efficiently to the heart, leading to long-term swelling, skin changes, and, in severe cases, venous ulcers.
Varicose veins are one of the most common vascular conditions worldwide, affecting a substantial proportion of adults at some point in their lives. They become progressively more common with age, and are consistently reported more frequently in women than in men, largely due to the influence of reproductive hormones on vein wall tone.
Occupations and lifestyles that involve long periods of standing or sitting, such as retail, healthcare, teaching, and office-based desk work, are also associated with a higher likelihood of developing them.
Symptoms of Varicose Veins
Not everyone with varicose veins experiences symptoms — some people notice only the visible, cosmetic appearance of the veins. When symptoms are present, they typically include:
- Aching or heaviness in the legs: A dull, tired, or weighed-down sensation in the legs, often worsening as the day progresses because blood has had more time to pool under the effect of gravity.
- Burning, throbbing, or cramping: Affected veins or the surrounding muscle tissue may throb or cramp, particularly at night, as circulation slows during periods of inactivity.
- Swelling in the lower legs and ankles: Pooled blood increases pressure within the veins, pushing fluid into the surrounding tissue and causing visible swelling, especially by the end of the day.
- Itching around the affected vein: Changes in local circulation and skin stretching over an enlarged vein can cause persistent itching in the immediate area.
- Skin discolouration: Prolonged pooling of blood can cause the skin over or around a varicose vein to darken or take on a brownish tinge, particularly near the ankles.
- Visible twisted, bulging veins: The hallmark sign, these veins are often described as looking like cords or ropes just beneath the skin, most commonly on the inside of the leg or behind the knee.
- Worsening pain after standing or sitting: Symptoms are typically most noticeable after long periods without movement, since the calf muscle pump — which helps return blood to the heart — is inactive during prolonged standing or sitting.
- Restless legs: Some people with varicose veins report an uncomfortable urge to move their legs, particularly in the evening or at night, thought to be related to poor venous return.
Causes of Varicose Veins
At the core of every varicose vein is a failure of the venous valve system. When the delicate, one-way valves inside a vein become weakened, stretched, or structurally damaged, they can no longer close completely after blood passes through. This allows blood to leak backward and accumulate in the vein below, a phenomenon known as venous reflux.
- Valve weakening: Valves can weaken over time due to natural wear and tear, sustained pressure, or a structural weakness in the vein wall itself, reducing their ability to snap shut and prevent backflow.
- Increased venous pressure: Anything that raises pressure within the leg veins — including prolonged standing, pregnancy, or excess body weight — places additional strain on valves and vein walls, accelerating their failure.
- Vein wall weakness: The walls of the veins themselves can lose elasticity and strength over time, causing them to stretch and bulge more easily even under normal pressure.
- Hormonal influence: Hormones such as oestrogen and progesterone are known to relax the smooth muscle within vein walls, which is part of why varicose veins are more common in women and often worsen during pregnancy or hormonal changes.
Risk Factors for Varicose Veins
A number of factors increase the likelihood of developing varicose veins:
- Obesity: Excess body weight places sustained additional pressure on the veins of the legs, making it harder for blood to be pumped back up to the heart and accelerating valve wear.
- Family history: Varicose veins tend to run in families, suggesting that inherited differences in vein wall strength and valve structure play a meaningful role in individual risk.
- Age: As the body ages, the valves within the veins experience natural wear and tear, gradually reducing their ability to prevent blood from flowing backward.
- Gender and hormonal changes: Women are more likely to develop varicose veins than men, as hormonal fluctuations during menstruation, pregnancy, and menopause can relax and weaken vein walls.
- Pregnancy: Pregnancy increases total blood volume and hormone levels while the growing uterus places direct pressure on the pelvic veins, all of which increase pressure in the leg veins.
- Prolonged standing or sitting: Remaining in one position for extended periods reduces the effectiveness of the calf muscle pump, allowing blood to pool under the constant pull of gravity.
- Previous blood clot or vein damage: A prior deep vein thrombosis (DVT) or injury to a leg vein can permanently damage the valves in that area, increasing the likelihood of varicose veins developing later.
- Smoking: Smoking damages blood vessels throughout the body and impairs healthy circulation, contributing to a higher risk of vein-related problems, including varicose veins.
Possible Complications of Varicose Veins
The great majority of varicose veins remain a mild, manageable condition throughout a person's life. However, if left untreated, more advanced cases can occasionally progress to complications that warrant closer medical attention:
- Superficial thrombophlebitis: A blood clot can form within a varicose vein close to the surface of the skin, causing localised redness, warmth, tenderness, and swelling along the affected vein.
- Venous (stasis) ulcers: Long-standing high pressure in the veins near the ankle can eventually damage the surrounding skin and tissue enough that it breaks down, forming a slow-healing open sore, most commonly near the inner ankle.
- Lipodermatosclerosis: Chronic venous pressure can cause the skin and fatty tissue of the lower leg to become hardened, thickened, and discoloured over time, sometimes giving the leg an "inverted champagne bottle" shape.
- Bleeding: Varicose veins located close to the skin's surface are thin-walled and under higher pressure than normal veins, meaning even a minor injury can cause them to bleed more than expected.
- Progression to chronic venous insufficiency: In some cases, longstanding untreated varicose veins can progress into a more persistent state of poor venous return, with more significant and continuous swelling and skin changes.
Varicose Veins and Pregnancy
Pregnancy is one of the most common triggers for the first appearance of varicose veins, affecting a significant proportion of pregnant women, particularly from the second trimester onward.
Several factors combine during pregnancy to increase pressure in the leg veins: total blood volume rises substantially to support the growing baby, hormone levels shift in ways that relax vein walls, and the enlarging uterus places direct physical pressure on the pelvic veins that drain blood from the legs.
- Timing of onset: Varicose veins often first appear or worsen during the second and third trimesters, when the combined effect of blood volume, hormones, and uterine pressure is greatest.
- Typical course after delivery: For many women, varicose veins that develop during pregnancy improve substantially or disappear entirely within a few months of delivery, as blood volume and hormone levels return to their pre-pregnancy state.
- Management during pregnancy: Compression stockings, regular gentle movement, and elevating the legs when resting are generally considered safe, first-line approaches for managing pregnancy-related varicose veins, with more invasive treatments typically deferred until after delivery unless symptoms are severe.
How Are Varicose Veins Diagnosed?
Varicose veins are often visibly apparent, but a proper diagnosis involves more than simply looking at the affected leg, as it is important to understand exactly which veins are affected and how severely.
- Physical examination: A doctor will examine the legs while the patient is standing, since veins are more visibly engorged in this position, checking for swelling, tenderness, skin changes, and the pattern of affected veins.
- Duplex ultrasound: The primary diagnostic tool for varicose veins, this painless imaging test uses sound waves to visualise blood flow within the veins in real time, allowing doctors to identify exactly where valves are failing and confirm the direction and severity of blood flow reversal.
- Venogram: In more complex or unclear cases, a specialised imaging test using a contrast dye injected into the veins may be used to provide a more detailed map of the venous system, though this is less commonly needed than ultrasound.
Lifestyle and Self-Management
Alongside formal treatment, everyday habits can meaningfully reduce symptoms and slow the progression of varicose veins:
- Maintaining a healthy weight: Reducing excess body weight lessens the sustained pressure placed on the leg veins, easing the workload on already weakened valves.
- Avoiding prolonged standing or sitting: Taking regular breaks to walk around, or shifting position periodically, helps prevent blood from pooling for extended periods in the lower legs.
- Wearing properly fitted clothing: Tight clothing around the waist, groin, or legs can restrict healthy blood flow, so well-fitted clothing helps support normal venous return.
- Staying physically active: Regular exercise, particularly activities that engage the calf muscles such as walking, cycling, or swimming, strengthens the body's natural mechanism for moving blood back toward the heart.
- Quitting smoking: Since smoking damages blood vessels and impairs circulation throughout the body, quitting supports healthier veins and reduces the likelihood of complications.
For most people, varicose veins are a manageable, long-term condition rather than a dangerous one, and many find that a combination of lifestyle adjustments and, where needed, minimally invasive treatment provides significant and lasting relief from symptoms.
Because varicose veins tend to be a progressive condition, meaning they generally do not improve on their own and may slowly worsen over time, many people find it useful to monitor any changes in their legs, such as new swelling, skin changes, or increasing discomfort, and to revisit their treatment plan periodically. Understanding the underlying cause of one's own varicose veins, and how personal risk factors such as occupation, weight, or family history may be contributing, allows for a more proactive and informed approach to long-term vein health.
