Spider angiomas (SAs), collections of small blood vessels radiating from a central, dilated arteriole that form near the surface of the skin, are found in 10-15% of healthy adults and young children, as well as in a variety of conditions, including pregnancy, women taking oral contraceptive pills (OCPs), thyrotoxicosis, and chronic liver disease1. Although the exact mechanism of their formation has not been fully elucidated, several hypotheses have been offered.
Some hypothesize that SAs form due to arteriolar vasodilation caused by estrogen excess that occurs as a result of impaired hepatic metabolism in cirrhosis2;this is supported by their association with other high-estrogen states, such as in pregnancy and OCP use. The vasodilatory effects of substance P, a neuropeptide partially inactivated by the liver and elevated in patients with liver disease, may also play a role3. Neovascularization promoted by vascular endothelial growth factor and basic fibroblast growth factor released by damaged hepatocytes has also been implicated4. Alcohol itself may contribute, as SAs are more commonly seen in individuals with alcoholic cirrhosis than in those with non-alcoholic causes of liver disease2.
For unknown reasons, in adults, spider angiomas most commonly occur in areas drained by the superior vena cava, namely the face, arms, neck, and chest.
- Khasnis A, Gokula RM. Spider nevus. J Postgrad Med 2002;48:307.
- Li CP, Lee FY, Hwang SJ, et al., Spider angiomas in patients with liver cirrhosis: role of alcoholism and impaired liver function. Scand J Gastroenterol 1999; 34: 520-3.
- Li CP, Lee FY, Hwang SJ, et al., Role of substance P in the pathogenesis of spider angiomas in patients with nonalcoholic liver cirrhosis. Am J Gastroenterol 1999; 94: 502-7.
- Li CP, Lee FY, Hwang SJ, et al., Spider angiomas in patients with liver cirrhosis: role of vascular endothelial growth factor and basic fibroblast growth factor. World J Gastroenterol 2003; 9: 2832-5.
Contributed by Camille Mathey-Andrews, Medical Student, Harvard Medical School