Red veins on my legs or spider veins on thighs are small, dilated blood vessels just beneath the skin (telangiectasias) that often look like red, blue, or purple webs. These veins emerge when the valves in superficial veins weaken, allowing blood to pool and pressure to build, causing vessels to bulge and branch. At USA Vein Clinics, vein specialists use diagnostic ultrasound and advanced treatments like sclerotherapy or laser therapy to close or eliminate spider veins. Early evaluation helps determine if there is underlying vein disease and guides effective, minimally invasive care.