Spider nevi [singular nevus] are common benign vascular lesion present in healthy people as well as associated with some disorders. Spider nevi are seen in 10-15% of healthy adults and young children that may appear as solitary or multiple lesions.
The name spider nevus is because of its physical appearance resembling a spider. It consists of a central red arteriole, or punctum or eminence, approximately 1 to 3 mm in size [ body of the spider], surrounded by radiating thin-walled capillaries [legs of spider].
Pulsations may occasionally be felt upon compression of the punctum.
In adults, spider nevi are seen on exposed areas such as the face, neck, upper trunk and arms.
However, in children, the backs of the hands and fingers are commonly affected.
Other names for spider nevus are
- Nevus araneus
- Spider angioma
- Spider telangiectasia.
Spider angiomas are thought to be more common in females.
Spider nevi are usually not caused by concern if there are no health symptoms or health conditions. But spider angiomas can be seen in liver diseases and hyperestrogenic states.
Causes and Pathophysiology of Spider Nevi
[Read more on skin anatomy]
Spider angioma is formed due to failure of the sphincteric muscle surrounding a cutaneous arteriole leading to dilatation of central arteriole.
Thus Spider angiomas occur as a result of the dilation of preexisting vessels.
They have been associated with estrogen-excess states [pregnancy, oral contraceptive use – the lesions resolve after delivery (6-9 months) or oral contraceptives are stopped.
These are also associated with thyrotoxicosis and liver disease, liver failure, and cirrhosis.
Spider nevi in liver disease are more in number, larger and often found in atypical locations.
The exact mechanism behind this is not known.
Possible mechanisms are
- Vasodilatory effects of alcohol [in alcoholic liver disease]
- Substance P
- Vasodilatory effect fo estrogen in hyperestrogenism [pregnancy, oral contraceptives]
- Inadequate hepatic metabolism of steroid hormones [liver disease]
- Angiogenesis as elevated serum vascular growth factors are seen in cirrhosis patients
- Vascular endothelial growth factor (VEGF)
- basic fibroblast growth factor (bFGF)
Solitary spider angiomas are seen in 15% of young adults. These generally have fewer than 3 lesions. Multiple spider angiomas are characteristic of chronic liver disease.
In fact, liver diseases like cirrhosis, alcoholic hepatitis, and hepatopulmonary syndrome have the highest prevalence of spider angiomas.
As a general rule, number and size of spider angioma correlate with the severity of the liver disease
Natural History and Clinical Significance of Spider Angiomas
Spider angiomas in younger adults usually disappear as the age advances. In a few persons, it may take several year
s.In females who take oral contraceptives, the spider nevi may resolve after the person stops taking the preparations.
Spider angiomas associated with pregnancy will disappear after delivery of the baby. Usually, they take 6-9 months.
In liver disease, multiple spider nevi are present. Especially in alcoholic liver disease, these may indicate
- Higher risk of mortality
- Higher chances of esophageal varices
- The extent of hepatic fibrosis.
- Number and size of spider angioma correlate with the severity of the liver disease
The patient would present with a red spot which is otherwise not symptomatic. A history of pregnancy, the oral contraceptive is necessary in female patients.
Any symptom suggestive of liver damage or any intake of the hepatotoxic drug should be noted.
Characteristic locations are on the face, neck, upper chest, and arms in adults. This corresponds to the distribution of superior vena cava.
In children, upper limbs, especially on the backs of the hands and fingers, are common locations.
The lesions are recognized by their characteristic appearance. Large spider angiomas may be pulsatile.
On examination, temperature over a spider nevus is higher than surrounding skin.
The lesion measures 1-3 mm in diameter but could be as large as 10 mm. Pressure blanches the lesion and it gets filled again on the release of pressure.
An examination of the abdomen is must with special attention to the liver and spleen.
Applying pressure over the body of a spider with a glass slide leads to pallor and refilling occurs following the release of pressure.
- Acneiform Eruptions
- Basal Cell Carcinoma
- Cherry Hemangioma
- Insect Bites
- Angioma Serpiginosum
- Osler-Weber-Rendu Syndrome
Solitary spider nevus or few nevi [up to three] in otherwise healthy individuals or pregnant women does not warrant further workup.
However, patients with extensive spider angioma should be evaluated for liver diseases or increased estrogen states.
Confirmation of the lesion can be done by diascopy which leads to blanching and refilling. The test can be done with a glass slide or finger.
In cases of doubtful diagnosis, a skin biopsy should be considered to rule out malignancy.
Histologically, the components of spider nevi are
- Arterial net
- Central arteriole
- Thin-walled ampulla [central arteriole ends in this]
- Efferent spider vessels
Treatment of Spider Nevi
Treatment of spider nevi is dependant on the cause. Patients with liver disease should be managed for that.
Spider nevi in healthy individuals usually disappear in a few years, in pregnancy following childbirth [6-9 months] and those related to oral contraceptive pills after discontinuation of medication.
Therefor no active treatment rquierd.
In children, some lesions resolve spontaneously, others may be permanent. But often no treatment is required. They generally regress over the course of many years.
Reports have described regression after liver transplantation in cirrhotic patients.
Rarely, fine-needle electrocautery, 585 nm pulsed, dye laser, 532 nm KTP (potassium-titanyl-phosphate) laser, or electro desiccation have been used to clear spider angioma for cosmetic concerns. The results of the procedure are generally good except for the small risk of the scar. Spider angiomas can recur after treatment.
- Khasnis A, Gokula RM. Spider nevus. J Postgrad Med. 2002 Oct-Dec. 48(4):307-9.
- Yalcin K, Ekin N, Atay A. Unusual presentations of spider angiomas. Liver Int. 2013 Mar. 33(3):487.
- Li CP, Lee FY, Hwang SJ, Lu RH, Lee WP, Chao Y, et al. Spider angiomas in patients with liver cirrhosis: role of vascular endothelial growth factor and basic fibroblast growth factor. World J Gastroenterol. 2003 Dec. 9(12):2832-5
- Sivarajan V, Al Aissami M, Maclaren W, Mackay IR. Recurrence of spider naevi following treatment with 585 nm pulsed dye laser. J Plast Reconstr Aesthet Surg. 2007. 60(6):668-71.