Spider angioma

A spider angioma or spider naevus (plural: spider naevi), also nevus araneus, is a type of telangiectasis (swollen, spider-like blood vessels on the skin) found slightly beneath the skin's surface, often containing a central red spot and deep reddish extensions (see Blood color) which radiate outwards like a spider's web or a spider's legs. They are common and often 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 and/or hepatitis C (HCV virus); 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 torso, and arms. 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 and women using hormonal contraception have spider angiomas, which is 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. Hepatitis C is an infection that can lead to irreversible liver damage. The hepatitis C virus (HCV) spreads through contaminated blood, and people are often infected by sharing drug paraphernalia or unsanitized tattoo guns and needles, piercing equipment, or manicure tools. To make matters worse, symptoms of HCV can take years to appear, and this is likely why most of those infected with hepatitis C do not even realize that they are infected, and can continue to spread the virus unknowingly.