Author: A/Prof Amanda Oakley, Dermatologist, Hamilton, New Zealand. December 2017.
Spider telangiectasis (plural telangiectases) is composed of dilated blood vessels. It is clinically characterised by its spider-like appearance. It is given that name because it has a central red papule (the body of the spider) from which fine red lines (the spider legs) extend radially. An alternative explanation for the name explains that the red lines form a spider web-like network. Other names are spider angioma (a misnomer, because it is not a proliferative disorder), spider naevus and naevus araneus.
Solitary spider telangiectasis is common in children and adults, affecting 10–15% of the population. Although they can affect people of any race, they are more easily seen in fair skin compared to skin of colour. Multiple spider telangiectases arise most frequently in pregnancy, in women taking a combined oral contraceptive pill, in patients with liver disease (particularly cirrhosis due to alcohol abuse), and in those with thyrotoxicosis.
Spider telangiectasis is an acquired vascular malformation. It occurs because of failure of a tiny muscle restricting the size of an arteriole. Increased pulsating flow through the vessel (the central papule) results in dilatation of distal vessels (the red lines).
Spider telangiectasis may arise spontaneously or may be induced by circulating oestrogen (which is increased in pregnancy, women taking combined oral contraceptives, and in liver disease). Various vascular endothelial growth factors may be involved.
Spider telangiectases are often located on the face, neck and upper chest (which has been postulated to relate to the distribution of a large vein draining the heart, the superior vena cava). They may also occur on the hands, arms or other sites. They vary in size and number, tending to be larger and more numerous in people with severe liver disease (when other cutaneous signs of liver disease may be present such as palmar erythema, leukonychia and jaundice). A central dilated arteriole may be present without radial capillaries, and the capillaries may vary in diameter, length and number. They can also be star-shaped.
The lesions may briefly bleed on trauma but otherwise do not cause any symptoms or complications.
A spider telangiectasis is diagnosed by its typical appearance. Compression on the central arteriole results in disappearance of the radial capillaries, which rapidly refill on relieving the compression. This is best seen through a transparent object such as a glass slide or the lens of a contact dermatoscope.
See DermNet's pages on angiomas and telangiectasia.
Spider telangiectasis is distinct from "spider veins", which are blue-coloured dilated venules (venulectasia) arising on thighs and lower legs and often associated with varicose veins.
Spider telangiectasis is harmless and does not require treatment. A lesion that is unsightly can be removed by destroying the feeding central arteriole, but may result in a small scar. Methods include:
Surgical excision is rarely necessary and inevitably leaves a scar.
Spider telangiectases can persist or disappear. In women, oestrogen-induced telangiectases often disappear within 6 months after having a baby or on stopping the combined contraceptive pill. They can reappear after initially successful treatment.
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