Port wine stains (PWS) are almost always evident at birth and are a capillary malformation. They are usually sporadic, although some occur in families in an apparently autosomal dominant inheritance. They are initially pink or red, and grow in proportion to infant growth. Although they may appear to lighten in the first few months, they generally darken after this.
They can be associated with other skin anomalies such as extensive mongolian spots. An important association is Sturge-Weber syndrome ( PWS+mental retardation ): PWS involving the forehead (V1 area of the trigeminal nerve), eye abnormalities (choroidal vascular abnormalities, glaucoma), and leptomeningeal and brain abnormalities (vascular malformations, calcification, or cerebral atrophy). Another association is Klippel-Trenaunay syndrome, with a capillary malformation and overgrowth of the soft tissue and bone of the affected limb.
Treatment of PWS is possible using a laser, although improvement rather than complete resolution is most common.