It’s common to notice visible veins on your hands, arms, or legs — especially if you’re lean, athletic, or aging. In many cases, these prominent veins are harmless, the result of low body fat, exercise, or genetics.

But sometimes, suddenly visible, bulging, or discolored veins can be more than just a cosmetic quirk. They can be early warning signs of underlying health issues — some of which are serious.

Here are 5 medical conditions that can cause noticeable veins — and what you should do about them.

1. Chronic Venous Insufficiency (CVI)
What it is:
A condition where the valves in your leg veins weaken or fail, making it harder for blood to flow back to the heart. As a result, blood pools in the legs, causing veins to stretch, bulge, and become visible.

Symptoms to watch for:

Veins that look twisted, rope-like, or swollen
Aching, heaviness, or cramping in the legs
Swelling in the ankles and calves
Skin discoloration (brownish tint) or venous ulcers near the ankles
Who’s at risk:

People who stand or sit for long periods
Pregnant women
Older adults
Those with a family history of vein problems
Why it matters:
Left untreated, CVI can lead to blood clots, skin infections, or open sores that are hard to heal.

2. Varicose Veins
What it is:
A common form of superficial vein dysfunction, where veins — usually in the legs — become enlarged, twisted, and dark blue or purple. While often seen as a cosmetic concern, varicose veins can signal deeper circulatory issues.

Symptoms: