Like thread veins, a spider angioma is a small blood vessel in the outer layers of the skin that remains dilated and is therefore visible through the surface of the skin. Many people have them, and they are common in both adults and children.

They get their name form their appearance, as with their small red central dot and radiating lines, they can look similar to spider webs. They can appear in various areas on the body, although the most common sites are the hands, forearms, ears, face and trunk. Pregnancy can also cause them to appear on the chest.

Those that appear in children or pregnant women may disappear on their own with time, although they are usually permanent in adults.

Thread veins assume a different appearance: they often form tiny lines rather than the form of a spider web. They, too, can be caused by hormonal changes and can become more common during pregnancy.

Laser thread vein removal is a possibility for those who find that they cause cosmetic problems. The treatment involves denaturing the cells lining the vessel walls, causing them to collapse and disintegrate. As the fragments of the destroyed vein are removed, the redness fades from the surface of the skin.