A port-wine mark is a type of birthmark that appears as a reddish-purplish discoloration on the skin. While it is a specific type of birthmark, there are several synonyms that can also be used to describe it. These include port-wine stain, nevus flammeus, vascular birthmark, and capillary malformation. Each of these terms refers to the same type of birthmark and can be used interchangeably. Port-wine marks are typically harmless, but they can sometimes be associated with underlying medical conditions, such as Sturge-Weber syndrome. If you or your child has a port-wine mark, it is important to discuss it with a healthcare professional to determine the best course of action.