Spider nevus.A Khasnis, RM Gokula
Department of Internal Medicine, Sparrow Health System and Michigan State University, East Lansing, MI 48824, USA. , USA
Correspondence Address: Source of Support: None, Conflict of Interest: None PMID: 12571391
Source of Support: None, Conflict of Interest: None
Keywords: Human, Telangiectasis, diagnosis,etiology,physiopathology,
Spider angioma, Spider nevus, Vascular spider, Nevus araneus, Arterial spider
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.
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. 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. Spider nevi also assist in the diagnosis of hepatopulmonary syndrome (HPS).
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. 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.
• Improving hepatic function
• Hypotension (Shock)
• Discontinuation of the offending medication
• Death (fade after death)
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.
1. 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. The presence of spider nevi is accompanied by an increased serum estradiol/free testosterone ratio in male cirrhotics.
2. 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. 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.
3. 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.
4. 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.
1. Vascular changes, such as telangiectasias, palmar erythema and paper money skin
2. Nail changes, particularly white nails
3. Changes of the mucous membranes, i.e. glossy tongue
4. Changes due to altered hormones, particularly female type of distribution of hair
5. Changes in the color of the skin like icterus and melanosis cutis
• 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
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.
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. Morphologic studies have revealed that a spider nevus has five components:
1. Cutaneous arterial net
2. Central spider arteriole
3. Subepidermal ampulla
4. Star shaped arrangement of efferent spider vessels
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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.
Usually no significant complications are associated with spider angiomas; however they are known to bleed profusely following minor trauma. Cosmetic issues may be of significant concern to some patients.
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 al 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. 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.