Varicose veins are swollen, twisted veins that bulge above the skin’s surface, typically measuring 3 millimeters or more in width. They most often appear on the calves and thighs as dark purple or blue rope-like cords. But not every case is obvious to the eye, and some varicose veins sit deep enough in the leg that you’ll only notice them through how your legs feel rather than how they look.
What Varicose Veins Look Like
The most recognizable sign is a vein that visibly bulges outward from the leg. Unlike spider veins, which are wispy lines less than 1 millimeter wide that sit flat against the skin, varicose veins are three-dimensional. You can feel them if you run your fingers over them. They often look like twisted, knotted cords beneath the skin, and their color ranges from dark blue to deep purple.
They show up most commonly along the inner calf, the back of the calf, and the inner thigh. Some people have a single prominent vein, while others develop clusters. The veins may follow a winding path rather than running in a straight line, which reflects the way the vein wall has stretched and lost its shape over time.
Symptoms You Can Feel
Many people with varicose veins notice symptoms before they ever see a bulging vein. The classic feeling is heaviness or tension in the legs, especially after long periods of sitting or standing. Other common sensations include aching, throbbing, burning, muscle cramping, itching around a vein, and a feeling of swelling even when the leg doesn’t look swollen. Some people describe restless legs or tingling.
These symptoms tend to follow a daily pattern. They’re usually mild or absent in the morning and worsen as the day goes on, particularly if your job keeps you on your feet or at a desk for hours. A useful clue: if elevating your legs above heart level for 15 minutes noticeably relieves the discomfort, that points toward a venous problem rather than a joint or muscle issue.
Women are significantly more likely than men to report these symptoms, particularly heaviness, aching, cramps, and itching. One large population survey (the Edinburgh Vein Study) found that many of these symptoms are common in the general population, but they become more frequent and more intense in people who have visible trunk varicose veins.
Varicose Veins You Can’t See
Your legs have two sets of veins: superficial veins near the skin and deep veins running through the interior of the leg. When a deep vein becomes varicose, it won’t produce a visible bulge. Instead, you may notice generalized leg swelling, persistent aching, a heavy feeling in both the leg and foot, or nighttime leg cramps with no obvious surface veins to explain them.
These hidden varicose veins can be harder to identify on your own. If you have ongoing leg symptoms without any visible vein changes, it’s worth having the blood flow in your legs evaluated, because deep varicose veins can also become sites where blood clots form.
A Simple Self-Check
You can do a basic self-assessment at home. Stand in front of a full-length mirror in good lighting and examine your legs from the front, sides, and back (use a hand mirror or your phone camera for the backs of your calves). Look for any veins that appear raised, twisted, or wider than the surrounding veins. Run your hands along your calves and thighs to feel for soft, ropy bulges under the skin.
Next, pay attention to what happens with position changes. Stand still for five to ten minutes and note whether your legs start to ache or feel heavy. Then lie down and prop your feet up on a pillow so they’re above your heart. If the discomfort eases within 15 minutes, that relief pattern is characteristic of venous insufficiency, the underlying problem behind varicose veins.
Also check the skin around any prominent veins. Darkening or brownish discoloration, dry or itchy patches, or skin that feels unusually firm or leathery are signs that the condition has been progressing. These skin changes indicate that elevated pressure in the veins has been affecting the surrounding tissue over time.
Why Varicose Veins Develop
Veins carry blood back to the heart, and they rely on one-way valves to keep that flow moving upward against gravity. In varicose veins, those valves have become weak or misshapen, allowing blood to flow backward and pool in the vein. The pooling raises pressure inside the vein, which stretches the vein wall further. That stretching prevents the valve from closing properly, creating a cycle that gradually worsens over time.
This process, called venous reflux, can start in the superficial veins near the skin, in the deep veins, or in the small connecting veins between those two systems. When valves in the connecting veins fail, higher-pressure blood from the deep system pushes into the superficial veins, which aren’t built to handle that load. The result is the characteristic bulging and twisting.
Spider Veins vs. Varicose Veins
Spider veins are thin, flat networks of tiny blood vessels less than 1 millimeter wide. They often look like fine blue or red lines branching across the skin. You typically can’t feel them with your fingertips. Varicose veins are at least 3 millimeters wide, raised above the skin’s surface, and palpable to the touch. Both conditions involve the superficial venous system, but varicose veins reflect a more significant degree of valve failure and carry a higher risk of complications.
Having spider veins doesn’t necessarily mean you’ll develop varicose veins, but both can coexist. If you see spider veins alongside symptoms like heaviness, aching, or swelling, it’s worth examining the area more closely for larger underlying veins that may not be immediately obvious.
Signs That Need Medical Attention
Varicose veins progress through a spectrum. In the early stages, you see surface veins and feel occasional discomfort. As the condition advances, persistent swelling develops in the ankles and lower legs. Further along, the skin begins to change: it may darken to a brownish color (from iron deposits left by leaking red blood cells), develop eczema-like patches, or become thickened and hardened, a condition called lipodermatosclerosis.
At the most advanced stage, the skin can break down into open sores, usually near the ankle. These venous ulcers heal slowly and tend to recur. A vein that suddenly becomes red, warm, hard, or painful may indicate a blood clot forming in the superficial vein. Bleeding from a varicose vein, even from a minor bump, can also occur because the vein wall is thin and sits close to the skin surface.
How Varicose Veins Are Confirmed
If your self-check raises concerns, a duplex ultrasound is the standard test used to confirm varicose veins and map out which valves are failing. It’s noninvasive, painless, and typically the only imaging test needed. The ultrasound combines a regular image of the vein’s structure with a measurement of blood flow direction and speed. A technician will watch for backward flow lasting longer than half a second after squeezing or releasing the calf, which confirms that the valves aren’t closing properly.
The test is usually performed while you’re standing, since gravity is what makes the reflux apparent. It can identify problems in both the superficial and deep venous systems, including those hidden varicose veins that produce symptoms without any visible bulge. The results help determine whether your veins simply need monitoring and lifestyle management, like regular leg elevation and compression, or whether they’d benefit from a procedure to close off the faulty veins.