A port-wine stain is a red stain that is present from birth.
The stain is in the skin (not on it) and is actually a dilation of the capillaries in the skin on that spot. In the beginning, it is light red and later it is somewhat darker. Sometimes starting from puberty it is purple-red. A port-wine stain won’t hurt but it can cause psychological problems. Treatment maybe with a laser, generally starting from the age of 8-11 years.
https://kidshealth.org/en/parents/port-wine-stains.html
(The FAQ’s booklet is produced by the Vascular Birthmarks Foundation USA).
A well-known person with a port-wine stain is Mikhail Gorbachev (former president of Russia).
