Spider angioma

A spider angioma or spider naevus (plural spider naevi) is a type of telangiectasis (swollen blood vessels) found slightly beneath the skin surface, often containing a central red spot and reddish extensions which radiate outwards like a spider's web. They are common and may be benign, presenting in around 10–15% of healthy adults and young children. However, having more than three spider angiomas is likely to be abnormal and may be a sign of liver disease. It also suggests the probability of esophageal varices. A spider angioma or spider naevus (plural spider naevi) is a type of telangiectasis (swollen blood vessels) found slightly beneath the skin surface, often containing a central red spot and reddish extensions which radiate outwards like a spider's web. They are common and may be benign, presenting in around 10–15% of healthy adults and young children. However, having more than three spider angiomas is likely to be abnormal and may be a sign of liver disease. It also suggests the probability of esophageal varices. Spider angiomas are found only in the distribution of the superior vena cava, and are thus commonly found on the face, neck, upper part of the trunk, and arms. They may also be present on the backs of the hands and fingers in young children. Spider angiomas form due to failure of the sphincteric muscle surrounding a cutaneous arteriole. The central red dot is the dilated arteriole and the red 'spider legs' are small capillaries carrying away the freely flowing blood. If momentary pressure is applied, it is possible to see the emptied capillaries refilling from the center. No other angiomas show this phenomenon. The dilation, in turn, is caused by increased estrogen levels in the blood. Many pregnant women, or women using hormonal contraception, have spider angiomas, due to high estrogen levels in their blood. Individuals with significant liver disease also show many spider angiomas, as their liver cannot metabolize circulating estrogens, specifically estrone, which derives from the androgen androstenedione. About 33% of patients with cirrhosis have spider angiomas. As such, microhemorrhages may be observed as spider angiomas.