Spider angioma, also known as spider nevus or nevus araneus, is a common form of telangiectasia involving the dilation of small blood vessels near the skin’s surface. This vascular lesion is characterized by a central body with fine, radiating vessels. Spider angiomas are generally considered benign. They represent a localized dilation of a small arteriole just beneath the epidermis.
Physical Characteristics and Location
A spider angioma features a bright red central spot, or punctum, typically 1 to 10 millimeters in diameter. Thin, reddish capillaries extend outward from this central arteriole, creating a web-like pattern. When pressure is applied, the entire mark temporarily disappears, or blanches, as blood is pushed out of the dilated vessels. The mark quickly refills from the center when pressure is released, which helps confirm the diagnosis.
These lesions are most frequently found on the face, neck, upper chest, and arms, corresponding to the distribution area of the superior vena cava. They are often located on sun-exposed areas of the body. Although most commonly seen on the upper body in adults, spider angiomas can appear anywhere on the skin, sometimes observed on the hands and fingers, particularly in children.
Underlying Causes and Medical Significance
Spider angiomas are caused by the dilation of a pre-existing cutaneous arteriole, though the exact mechanism leading to this vasodilation is not fully understood. Many solitary lesions are idiopathic, arising spontaneously in healthy individuals, including up to 15% of adults and many children. Hormonal fluctuations are a significant factor, as these lesions are often linked to elevated estrogen levels. This hormonal connection explains why spider angiomas are common during pregnancy and in individuals using oral contraceptives.
The appearance of multiple spider angiomas (more than three lesions) holds greater medical significance and often prompts further investigation. Numerous lesions are frequently associated with serious underlying health conditions, most notably chronic liver disease, such as cirrhosis or alcoholic hepatitis. Liver impairment can lead to inadequate metabolism of circulating estrogen, which is thought to trigger arteriolar dilation; the number of angiomas can correlate with the severity of liver damage. Other conditions, including rheumatoid arthritis and thyrotoxicosis, have also been associated with multiple spider angiomas. If multiple lesions appear suddenly, a clinical evaluation is recommended to rule out a systemic cause.
Removal Methods
Treatment for spider angiomas is typically not medically necessary because the lesions are benign and may resolve on their own, especially those linked to pregnancy or hormonal medications. For lesions that persist or are cosmetically bothersome, several effective removal techniques are available. The most common approach involves specialized vascular lasers, such as the pulsed dye laser (PDL) or the KTP laser.
These laser treatments emit a concentrated beam of light absorbed by hemoglobin, selectively heating and destroying the dilated vessels without significantly damaging the surrounding skin. Another common method is electrocautery, or electrodesiccation, where a fine electric needle is used to heat and coagulate the central arteriole. Both laser and electrocautery treatments are generally performed in an outpatient setting and usually require only one session for complete removal. While the procedures carry a small risk of scarring, they are generally successful, though recurrence is possible.