Spider angioma is a group of abnormal blood vessel that produces the appearance of a spider-web on the surface of the skin. Spider Angioma is a skin condition and a form of telangiectasis - a lesion produced by telangiectasia (a vascular lesion formed by the dilation of a group of small blood vessels) which may be present as a coarse or fine, red line, or as a punctum (point or small spot) with radiating limbs (spider). This is also called spider nevus. Spider angiomas are painless,
and those who have them generally experience no symptoms.
A spider angioma is formed when a group of blood vessels dilates in a characteristic "spider leg" pattern. A spider angioma can be seen in a healthy person without any apparent cause, but is more common in individuals with liver disease or altered hormone levels. It is characterized by a central and elevated red dot, about the size of a pinhead, from which small blood vessels radiate (looking like a spider), spider angiomas are often associated with high estrogen levels as occur in pregnancy or when the liver is diseased and unable to detoxify estrogens. Small numbers of spider nevi are common in children and pregnant women. However, in large quantities, spider nevi may be a sign of an underlying disorder, such as advanced cirrhosis of the liver.
Lesions resembling multiple spider nevi (but without the "spider legs") may be a sign of hereditary hemorrhagic telangiectasia, a disorder of the blood vessels that causes bleeding and iron-deficiency anemia. Most patients with hepatic cirrhosis develop many hepatic spiders that may become quite prominent. Many women develop lesions during pregnancy or while taking oral contraceptives. As spiders are asymptomatic (producing no symptoms) and usually resolve spontaneously in about six to nine months postpartum or after discontinuing oral contraceptives, treatment is generally not required. If resolution is not spontaneous or treatment is required for cosmetic purposes, the central arteriole can be destroyed with fine needle electrodessication (sealing off of blood vessels by monopolar high frequency electric current). Some physicians may suggest treatment with lasers, but this is often more expensive.
Liver disease such as cirrhosis may sometimes be avoided if the person stops drinking alcohol. Spider angioma may be a side effect of estrogen therapy, so could be avoided if the woman does not take estrogen. In normal persons without these risk factors, the cause of the spider angioma is unknown and prevention is not possible.