Nevus Araneus (Spider Nevus)

Updated: May 11, 2018
  • Author: Sarah Sweeney Pinney, MD; Chief Editor: Dirk M Elston, MD  more...
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Overview

Background

Nevus araneus, also known as spider angioma or spider nevus, is a common benign vascular lesion present in 10-15% of healthy adults and young children. [1, 2] They may appear as a solitary or multiple lesions. [2] In particular, when multiple lesions are present, liver disease, estrogen therapy, and thyrotoxicosis should be considered. The name stems from its physical appearance, which is characterized by a central red arteriole, or punctum, representing the body of the spider, surrounded by a radial pattern of thin-walled capillaries, resembling legs (see the image below).

A spider nevus consists of a central arteriole wit A spider nevus consists of a central arteriole with radiating thin-walled vessels. Compression of the central vessel produces blanching and temporarily obliterates the lesion. When released, the threadlike vessels quickly refill with blood from the central arteriole. The ascending central arteriole resembles a spider's body, and the radiating fine vessels resemble multiple spider legs.

Nevus araneus lesions range in size from 1-10 mm in diameter. Compression of the central vessel with a slide (diascopy) results in blanching and temporary obliteration of the lesion, which is followed by rapid return of blood flow upon release. [1] Pulsations may occasionally be felt upon compression of the punctum. [3] In adults, these lesions are most frequently found on exposed areas of the body, such as the face, neck, upper trunk (above the nipple line), and arms. In children, the backs of the hands and fingers are commonly affected. [1, 3]

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Pathophysiology

Vascular malformations can be classified into 6 categories: hamartomas, malformations, dilatations of preexisting vessels, hyperplasias, benign neoplasms, and malignant neoplasms. [3] Spider angiomas (nevus araneus) are not vascular proliferations; they occur as a result of the dilation of preexisting vessels. [1, 3]

While most lesions are unrelated to internal disease, spider angiomas (nevus araneus) have been associated with thyrotoxicosis, [4] and frequently occur in the presence of estrogen-excess states, such as pregnancy or during the use of oral contraceptives. Resolution of lesions in this context is common 6-9 months postpartum or after discontinuation of oral contraceptive medication. [5]

Spider angiomas (nevus araneus) are also associated with liver disease, liver failure, and cirrhosis. [6, 7, 8] In fact, the spider angioma is rumored to have received its name from barmaids in New York, who used the lesion as a marker of liver disease in their customers. [4] When associated with liver disease, spider angiomas may be numerous, large in size, [9] and appear in atypical locations [10] ; other findings may be present, including palmar erythema, muscle atrophy, gynecomastia, ascites, jaundice, splenomegaly, [4] leukonychia, onychomycosis, and longitudinal nail striations. [11] The number of lesions may be indicative of the extent of hepatic fibrosis. [8]

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Etiology

The exact etiology of the spider nevus (nevus araneus) is unclear. Estrogen-excess states such as pregnancy and liver disease have been associated with spider angiomas for many years. This hypothesis is partially based on the hormone’s dilating effects on endometrial spiral arterioles during pregnancy. [12] Additionally, other biologic substances, including vascular endothelial growth factor (VEGF), [13] basic fibroblastic growth factor (bFGF), [14] substance P, and endogenous vasodilators, [12] have been implicated in the pathogenesis of spider angioma (nevus araneus). One study demonstrated that although the ratio of estrogen to testosterone in the serum of cirrhotic patients did, in fact, vary inversely with liver function, the numbers never reached statistical significance. [12]

In the context of liver disease, spider nevi are found more commonly in alcoholic cirrhotics versus nonalcoholic cirrhotics, [15] as well as disease secondary to alcohol abuse versus that caused by viral hepatitis. [16]

Children with liver disease rarely have large numbers of spider angiomas. Although the finding of 5 or more spider angiomas is more common in persons with liver disease, many healthy children also have one or more of these lesions. [2]

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Epidemiology

Frequency

United States

Young children and pregnant women most frequently exhibit spider angioma (nevus araneus) lesions. In pregnant women, palmar erythema may also be present. [5] Spider angiomas are common in otherwise healthy children and are present in 10-15% of healthy adults and young children. [1]

International

The frequency of spider angiomas (nevus araneus) is presumed to be similar to that in the United States.

Race

No racial predilection is reported for spider angioma (nevus araneus), but lesions are more apparent in light-skinned patients.

Sex

Spider angiomas (nevus araneus) are more common in women than in men, although a definitive study documenting this is not available. Young children of both sexes and pregnant women frequently exhibit lesions. [2, 5]

Age

One study demonstrated that 38% percent of healthy, school-aged children (ages 5-15 y) had at least one spider nevus (nevus araneus), while most had 1-4 lesions. The trend was an increasing number of lesions with increasing age. [2] Spider angiomas also are common in women of childbearing age in association with pregnancy or oral contraceptive use. [5]

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Prognosis

Spider angiomas (nevus araneus) are asymptomatic benign lesions. When extensive, they may be associated with significant underlying internal pathology, such as liver disease. [6, 7, 8] Spider angiomas (nevus araneus) also may produce significant cosmetic concerns in some patients.

When not associated with underling pathology or pregnancy, spider angioma (nevus araneus) lesions may be permanent or may regress over a number of years. Recurrence is not uncommon after treatment. [17, 18, 19, 20, 21, 22, 23, 24]

Although a finding of 5 or more spider nevi is common in children with liver disease, this quantity can also be present in many healthy children. [2] In association with liver disease, lesions may resolve after liver transplantation. [6]

Spider nevi occurring in the context of pregnancy or oral contraceptive use may regress postpartum or after discontinuation of medicine. [5] They may also regress after death or in situations resulting in severe hypotension. [1]

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