what are spider veins
Spider veins are tiny, thin veins that can be seen very close to the skinâs surface. They look like red, blue, or green spider webs just beneath the skin. Sometimes they are also described as looking like marble.Spider veins are caused by a backup of blood.These become nonfunctional, âdead-endâ veins.pider Veins. Spider veins are tiny, thin veins that can be seen very close to the skinâs surface. They look like red, blue, or green spider webs just beneath the skin. Sometimes they are also described as looking like marble. Spider veins are caused by a backup of blood.