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 the formation SAs has not been fully elucidated, several hypotheses have been offered:
- Arteriolar vasodilation caused by estrogen excess due to impaired hepatic metabolism in cirrhosis; 2this is supported by the association of SAs also with other high-estrogen states, such as in pregnancy and OCPs.
- Vasodilatory effects of substance P, a neuropeptide partially inactivated by the liver and elevated in patients with liver disease. 3
- Neovascularization promoted by vascular endothelial growth factor and basic fibroblast growth factor released by damaged hepatocytes. 4
- Alcohol itself may contribute, as SAs are more commonly seen in individuals with alcoholic cirrhosis than in those with non-alcoholic causes of liver disease. 2
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.https://www.ncbi.nlm.nih.gov/pubmed/10423070
- 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.https://www.ncbi.nlm.nih.gov/pubmed/10022654
- 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. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4612064/
Contributed by Camille Mathey-Andrews, Medical Student, Harvard Medical School