Vein care · Patient education

Spider veins vs varicose veins: how to tell the difference, and when each one needs treatment.

They get lumped together, treated with the same creams, and blamed on the same things. But one is usually a surface concern and the other can be a sign that a valve inside your leg has stopped doing its job. Knowing which one you're looking at changes what to do next.

The 30-second answer

	Spider veins	Varicose veins
Look	Thin red, blue, or purple lines in web or branch patterns	Rope-like, bulging, often twisted cords under the skin
Size	Under about 1 mm, flat or nearly flat	3 mm or wider, raised enough to feel
Feel	Usually nothing	Often aching, heaviness, throbbing, or night cramps by evening
Usual cause	Dilated capillaries near the surface	A failed one-way valve letting blood fall backward and pool
Treatment	Cosmetic: sclerotherapy or laser	Assessment first; often a catheter procedure that seals the failed vein

That's the short version. The longer version matters, because the two conditions overlap in one important way: sometimes the small veins you can see are being fed by a bigger problem you can't.

What spider veins actually are

Spider veins (the medical term is telangiectasias) are tiny blood vessels sitting just under the surface of the skin that have widened enough to become visible. They show up as red, blue, or purple threads, often in a web, starburst, or branch pattern, most commonly on the thighs, behind the knees, around the ankles, and on the face.

They're extremely common, more so with age, pregnancy, hormonal changes, sun exposure, and a family history of the same. Standing occupations don't help either.

Here's the part most people find reassuring: on their own, spider veins are almost always harmless. They don't usually hurt, they don't damage the leg, and treating them is a cosmetic decision, not a medical necessity.

What varicose veins actually are

Varicose veins are a different structure with a different story. These are larger veins, 3 millimetres and up, that bulge, twist, and rise above the skin like soft cords. And they're not just a bigger version of spider veins. They usually exist because something mechanical has gone wrong.

The veins in your legs carry blood back up toward the heart, against gravity, using a chain of one-way valves. When one of those valves stops closing properly, blood falls backward each time you stand and pools in the vein below. Pressure builds through the day. The vein stretches, and a stretched vein holds more blood, which stretches it further. Clinicians call this venous reflux, and it's the engine behind most true varicose veins.

That's why varicose veins so often come with company: legs that feel heavy or tired by late afternoon, aching or throbbing after a day on your feet, swelling around the ankle, itching over the vein, cramps or restless legs at night.

The overlap nobody mentions: when spider veins are a clue

Most spider veins are exactly what they look like. But in some legs, clusters of spider veins, especially around the inner ankle or lower calf, are the visible tip of underlying reflux in a deeper vein. Treat only the surface in that situation and the result tends to be disappointing: the little veins fade, then new ones arrive, because the pressure that created them is still there.

This is why a good vein practice doesn't reach straight for the laser. If your spider veins keep coming back, sit low on the leg, or travel with any of the symptoms above, the first step is a duplex ultrasound: a painless scan that maps how blood is actually moving in the leg and shows whether a valve has failed. It takes about 20 minutes and it answers the question properly instead of guessing.

Why the usual fixes disappoint

Creams and supplements don't repair valves or shrink established veins; nothing you rub on the skin reaches the mechanics underneath. Elevation helps drain the leg while you're horizontal, and compression stockings really do ease symptoms by squeezing the leg and supporting the column of blood. But notice what all of these have in common: they manage pressure. None of them can close a valve that no longer closes.

That's not a reason to skip stockings; it's a reason to understand what they are. They're symptom control, and for some people that's enough. When it isn't, the question becomes whether the source can be fixed.

How each one is treated

Spider veins

When treatment is wanted, it's cosmetic and done in clinic. Sclerotherapy uses a fine needle to place a solution inside the vessel that causes it to close and fade over the following weeks. Laser treatment does similar work with light, and suits some vessel types and skin areas better. Both are short visits, and both work best once any underlying reflux has been ruled out or dealt with first.

Varicose veins

When ultrasound confirms a refluxing vein, modern treatment looks very little like the vein stripping people remember. Radiofrequency ablation (RFA) seals the failed vein from the inside through a single needle entry, under local anesthetic, in about 45 minutes, with most people walking out the same day. Blood reroutes through the many healthy veins nearby. In published five-year European data, 91.9% of treated veins remained closed.

We've written a deeper guide on this: how the procedure works, what recovery looks like, and who it suits.

When to stop watching and get assessed

None of these mean something terrible is happening today. They mean the process is active rather than parked, and vein disease is progressive: valves don't heal themselves, and skin changes that are allowed to advance become harder to reverse. An ultrasound settles what's actually going on.

A note on referrals and coverage in Ontario

Assessment and medically indicated treatment of symptomatic venous disease may be covered by OHIP with a referral from your family doctor. Treatment done purely for appearance, which includes most spider vein work, is cosmetic and isn't covered. If you're not sure which side of that line you're on, that's a normal question, and it's exactly what the consultation is for.

Common questions