High flow vascular stains (HFVS) are lesions which have the appearance of capillary malformations (CMs)/ port wine stains (PWS) but are associated with increased arterial flow.Identify features of HFVS that differentiate them from typical "slow flow" PWS.Retrospective multicenter cohort study of HFVS evaluated across seven centers was conducted. HFVS were characterized by clinical features (warmth, thrill, rapid capillary refill), radiologic findings (fast flow), or mutations associated with CM-arteriovenous malformation (CM-AVM) syndrome. Photographs were reviewed by investigators.70 patients with HFVS were reviewed (47 multifocal and 23 solitary). The majority were flat (77%), warm to touch (60%) and red or pink-red in color (35%) with heterogeneous color saturation (73%) and well-defined borders (71%). Regional soft tissue swelling/ overgrowth was common (47%). Head and neck location was most common (38%). Among 34 cases with photographic review over time, all demonstrated changes in appearance.Retrospective design, recall bias, lack of standardized time points or visual analog scale and image variability.Heterogeneity of stain color saturation, warmth to touch, peripheral pallor and overgrowth/soft tissue swelling help distinguish HFVS from PWS. Darkening of color and increased border demarcation may develop over time. These findings raise suspicion for HFVS and provide an indication to assess for extracutaneous involvement.