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Journal of Postgraduate Medicine
Medknow Publications and Staff Society of Seth GS Medical College and KEM Hospital, Mumbai, India
ISSN: 0022-3859 EISSN: 0972-2823
Vol. 48, Num. 4, 2002, pp. 307-309
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Journal of Postgraduate Medicine, Vol. 48, Issue
4, 2002 pp. 307-309
Spider Nevus
Khasnis A, Gokula RM
Departments of Internal Medicine and Family Practice, Sparrow Health System
and Michigan State University, East Lansing, MI 48824, USA.
Address for Correspondence: Atul Khasnis
M.D., 1107 University Village Apts., Apt E, East Lansing, MI 48823, USA E-mail:
khasatul@yahoo.com
Code Number: jp02102
Synonyms
Spider angioma, Spider nevus, Vascular spider, Nevus araneus, Arterial spider
Description
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; hence the
name. The size can vary from a pinhead to 0.5 cm in diameter. The blood pressure
in these small arterioles has been measured to be 50 to 70 mm Hg and the temperature
is 2-3°C higher than the surrounding skin.1
Background
Spider nevi may be benign or indicative of underlying systemic disease. They
are seen in 10-15% of healthy adults and young children. Most lesions are unrelated
to internal disease. Lesions developing during pregnancy or due to oral contraceptives
usually resolve spontaneously after delivery or on discontinuing the medication.
They may also be seen in thyrotoxicosis, patients with rheumatoid arthritis
receiving estrogen therapy and women on oral contraceptives.1 Numerous
prominent spider angiomas are one of the strong clinical pointers to severe
liver dysfunction in patients with alcoholic liver disease. Spider nevi can
be used as one of the most useful parameters for predicting the grade and stage
of Hepatitis C with moderate accuracy.2 Spider nevi also assist in
the diagnosis of hepatopulmonary syndrome (HPS).
Sites
In adults, spider nevi are usually seen over the face, neck, and upper part
of the trunk, and arms (vascular territory of the superior vena cava). It is
unusual to find them below a line joining the nipples.3 They may
also be occasionally seen in the mucous membrane of the nose, mouth or pharynx.
In young children, they may be found on back of the hands and fingers. In a
patient with cirrhosis, multiple pleural and subpleural arteriolar nevi were
demonstrated on gross and microscopic examination at autopsy.4
When do Spider Nevi Disappear?
- Improving hepatic function
- Hypotension (Shock)
- Discontinuation of the offending medication
- Death (fade after death)
Pathophysiology
The pathogenesis of spider nevi is still unclear. Their
occurrence is supposed to be related to dilatation of
pre-existent blood vessels rather than true vascular
proliferation.5
- Increased plasma levels of estrogen, vascular dilation, and neovascularisation
are possible etiologies. A study was carried out to elucidate the relationship
between spider angiomas, plasma levels of sex hormones, various vasodilators
and hemodynamic parameters in patients with non-alcoholic cirrhosis. The study
demonstrated that the levels of substance P were elevated in these patients
and it is postulated that this substance may play an important role in the
pathogenesis of spider angiomas.6 The presence of spider nevi is
accompanied by an increased serum estradiol/free testosterone ratio in male
cirrhotics.7
- Alcohol is another important possible cause. In a study carried out among
patients with alcoholic cirrhosis, it was found that alcoholism and impaired
liver function are important predictors of the presence of spider angiomas
in patients with liver cirrhosis.8 Multiple spider angiomata are
more frequent in patients with alcoholic cirrhosis and in those with cirrhosis
due to hepatitis C viral infection and alcohol ingestion than in patients
with cirrhosis purely due to hepatitis C virus.9
- Hepatic cirrhosis is associated with generalised hyperdynamic circulation
and spider angioma is a cutaneous manifestation of such a circulation. This
was demonstrated by arteriography and gas analyses of blood aspirated from
a vascular spider in a patient with hepatic cirrhosis before excision and
histologic examination of the lesion.10
- Oesophageal varices are associated with the hepatopulmonary syndrome and
portal-pulmonary vein anastomoses. These could produce arterial hypoxemia
because the deoxygenated portal venous blood can mix with oxygenated pulmonary
venous blood. As portal pressures increase, the mediastinal veins enlarge;
they may penetrate the pleura and drain into pulmonary veins. Direct splenic
injections in patients, however, suggest that this shunt pathway is uncommon
and small. Dilatation of capillaries may allow a more rapid flow of blood
through the lungs and the greater distance between the erythrocyte and alveolar
wall may make oxygenation of rapidly passing erythrocytes difficult to achieve.
The abnormalities in the perfusion lung scan and contrast echocardiogram cannot
be explained on the basis of porta-pulmonary shunting and their presence indicates
that porta-pulmonary shunting is unlikely to be the dominant mechanism. Pulmonary
hypertension may rarely occur in chronic liver disease even without arterial
hypoxaemia.11
Other Cutaneous Signs of Liver Disease
- Vascular changes, such as telangiectasias, palmar erythema and paper money
skin
- Nail changes, particularly white nails
- Changes of the mucous membranes, i.e. glossy tongue
- Changes due to altered hormones, particularly female type of distribution
of hair
- Changes in the color of the skin like icterus and melanosis cutis
Clinical Approach to a Patient With Spider Nevi
- Detailed history of alcohol abuse (duration, type and amount, pattern of
consumption)
- Ask female patients regarding hormonal supplements, or use of oral contraceptives
- History of other medications causing liver damage
- Detailed general examination
- Meticulous examination of the liver - palpation, percussion (for liver span),
auscultation (for bruits)
- Careful examination for other signs of liver cell failure; especially cutaneous
markers
- Laboratory evaluation to assess the severity and etiology of the liver disease
- Arterial blood gas examination in patients with cirrhosis and clubbing (for
HPS)
- Do not forget pregnancy as a possible cause in a young female patient with
no evidence of liver disease
- Keep in mind list of differential diagnosis and relevant work-up
Examination of Spider Nevi
Spider angiomas usually are bright red with a small (1
mm), central, red papule surrounded by several distinct
radiating vessels. The entire lesion usually is 0.5-1 cm in diameter.
Pressure on the lesion causes it to disappear. The pressure can
be applied with a pinhead or a glass slide (diascopy).
Blanching is replaced by rapid refill from the central arteriole when
pressure is released. This refilling is important to observe
because the pattern of filling (from center to periphery
demonstrates the arteriolar origin of the spider nevus). Occasionally,
pulsation of the central papule is noted. Lesions occur most
commonly on the face, below the eyes, and over the
cheekbones. Other common sites include the hands, forearms, and
ears. Pregnant women and individuals with liver disease may
demonstrate associated palmar erythema. Patients with
significant internal disease may exhibit numerous prominent lesions
over the trunk and face. These patients should be examined for
the presence of palmar erythema, white nails with distal
hyperemic bands, splenomegaly, ascites, jaundice, and asterixis.
Spider nevi may also be associated with numerous small vessels
scattered randomly through the skin on the upper arms
(paper money skin). White spots observed on the arms and
buttocks on cooling the local area constitute another associated
dermatological feature. Each of these spots represents the
beginning of a spider nevus.3
Histologic Findings
A central ascending arteriole ends in a thin-walled
ampulla just below the epidermis. This ampulla feeds the thin
delicate arterial branches that radiate peripherally into the
superficial dermis. Usually, no significant inflammatory changes are
noted. Glomus cells have been reported in the wall of the
central arteriole.12 Morphologic
studies1 have revealed that a spider nevus has five components:
- Cutaneous arterial net
- Central spider arteriole
- Subepidermal ampulla
- Star shaped arrangement of efferent spider vessels
- Capillaries
Differential Diagnosis
- Cherry Hemangioma
- Insect Bites
- Rendu-Osler Weber Syndrome
- Angiokeratoma Corporis Circumscriptum (Fabry)
- Angiokeratoma Corporis Diffusum( Fabry)
- Angioma Serpiginosum
- Ataxia Telangiectatica
- Disseminated Essential Telangiectasia
- Senile Angioma
Treatment
Children do not require any specific treatment as these
lesions are known to fade and resolve spontaneously over time.
Electrodesiccation and laser treatments under local
anaesthesia are effective therapeutic procedures for facial spider
angiomas. Both modalities of treatment bring about good results.
Occasionally recurrence may be seen.
Complications of Treatment
Usually no significant complications is associated with
spider angiomas; however they are known to bleed profusely
following minor trauma. Cosmetic issues may be of significant
concern to some patients.
Importance of Spider Nevi
Many recent studies have highlighted the importance of spider nevi as a useful
sign for the assessment of severity of various hepatic diseases. Romagnuolo
et al2 found that spider nevi and thrombocytopaenia, with either
splenomegaly or hypoalbuminaemia, were useful for predicting the presence of
hepatic fibrosis in patients with Hepatitis C infection. Hepatopulmonary syndrome
occurs in individuals with advanced hepatic cirrhosis and the intra-pulmonary
arteriovenous shunts that occur in this condition significantly compound the
existing haemodynamic status. Patients with HPS have significantly higher incidence
of dyspnea, platypnea, clubbing and spider nevi.13 Thus, this small,
yet valuable, physical sign must be carefully looked for in patients with liver
disease as it can provide important information not only regarding severity
but also prognosis of the illness.
References
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- Li CP, Lee FY, Hwang SJ, Chang FY, Lin HC, Lu RH, et al. Role of substance
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