A port-wine stain also know as naevus flammeus is a vascular birthmark consisting of superficial and deep dilated capillaries in the skin which produce a reddish to purplish discolouration of the skin. They are so called for their colour, resembling that of port wine. It is part of the family of disorders known as vascular malformations.
The two terms are not always equated. Sometimes the term "naevus flammeus" is divided into two categories: port-wine stain and salmon patch
Port-wine stains are present at birth and persist throughout life. The area of skin affected grows in proportion to general growth. Port-wine stains occur most often on the face but can appear anywhere on the body. Early stains are usually flat and pink in appearance. As the child matures, the colour may deepen to a dark red or purplish colour. In adulthood, thickening of the lesion or the development of small lumps may occur