They are approx. 3-10 mm long and 1 mm wide red blood vessels. They often have the shape of a small snake, but can also be straight. Sometimes a light pressure against the skin will make them less visible. They can appear anywhere, but are most common on the face of the elderly. They usually only cause cosmetic problems.
It is often a sign of aging of the skin, and people who have been in the sun a lot get this more easily. In the skin disease rosacea, there are many such blood vessels on the face. Pregnancy, liver disease and drugs (cortisone) can trigger this. In basal cell cancer, such blood vessels will be present and sometimes telangiectasias can also be an expression of other skin diseases.
Treatment is not necessary. They can be burned away by a doctor. Laser treatment can be effective, especially if you have many of these, but often has to be performed several times.