When to Worry About Veins That Appear Out of Nowhere

Veins bulge when blood pools in weakened or damaged veins, rather than flowing smoothly back to the heart. This often results in varicose veins—swollen, twisted veins that typically appear on the legs but can also show up on the arms.

While visible veins are usually a cosmetic or temporary issue, a sudden or unexplained change might warrant a closer look. Some medical conditions that can cause more prominent veins include:

Phlebitis: Inflammation in the veins that can cause tenderness and swelling.

Varicose veins: Enlarged, twisted veins that may be accompanied by discomfort.

Deep vein thrombosis (DVT): A more serious condition involving blood clots, usually in the legs.