Snapshot A 5-week-old girl is brought into the pediatrician’s office for evaluation of a birth mark. According to her mom, this red birthmark has been present since birth and has not really changed. Physical exam shows that she has a pink-to-purple macular patch involving the left cheek. The lesion is unilateral with a sharply demarcated border along the facial midline. Her parents are counseled about the fact that this lesion may persist for her entire life. A referral is made to a pediatric dermatologist for potential pulsed dye laser therapy. Introduction Clinical definition a type of benign capillary malformation that presents as a purplish “port-wine” colored birthmark on the face and neck also known as nevus flammeus Genetics Sturge-Weber syndrome inheritance pattern autosomal dominant mutations GNAQ activating mutation Associated conditions Sturge-Weber syndrome, also known as encephalotrigeminal angiomatosis glaucoma especially with periorbital port-wine stains eczematous dermatitis Epidemiology Incidence < 1% of newborns Demographics commonly involves newborns most common vascular malformation of the skin Location face and neck Risk factors family history ETIOLOGY Pathogenesis caused by ectatic superficial papillary dermal capillaries characterized by vascular dilatation and no proliferation thought to result from neural deficiency of sympathetic innervation of the blood vessels ↑ vascular endothelial growth factor (VEGF) inducing vasodilation Presentation Symptoms persistent purple or dark red birth mark present on face since birth asymptomatic Physical exam in childhood pink, red, or purple flat macular patch with well-demarcated borders blanches somewhat with external pressure in adulthood, lesion may progress to deep-red or purple become raised and papular with cobblestone-like surface location most lesions are in one of the divisions of the trigeminal nerve typically unilateral Imaging MRI with gadolinium indication if Sturge-Weber syndrome is suspected Studies Making the diagnosis a clinical diagnosis Differential Capillary hemangioma Treatment Conservative cosmetic cover-up indication if lesions are a source of psychological stress for patients Procedural pulsed dye laser therapy indications first-line treatment if lesions are a source of psychological stress for patients can lead to lightening of port-wine stain without any scarring Complications Cosmetic disfigurement and associated psychosocial impairment Prognosis Port-wine stains are present at birth and do not spontaneously resolve Lesions become thicker and darker with increasing age