A superficial spider-like cluster of capillaries composed of a central ‘feeder’ vessel and multiple minute tortuous and dilated radiating vessels with a peripheral erythaema; when the involved vessel is large, it may pulsate and blanch on pressure; while classically due to increased circulating oestrogens as seen in pregnancy and alcoholic cirrhosis, SAs may occur in chronic hepatic congestion 2º to constrictive pericarditis and may be a normal birthmark in children
