What Causes Spider Veins?

Also known as thread veins, spider veins are small clusters of veins that form just beneath the surface of the skin. These clusters often resemble a spider's legs, and they result in red, purple, or blue discoloration. Spider veins are most prevalent in women, and they frequently appear on the thighs, ankles, calves, and face. Most spider veins are easily visible beneath the skin, and this can cause patients to feel self-conscious. Unlike varicose veins, spider veins do not produce bulges under the skin; they are level with the skin's surface.