What is a spider angioma?

What is spider angioma | Causes | Symptoms | Treatment | Prevention | Diagnosis

Although a spider angioma might sound like an insect crawling through your body, this condition is unrelated to the hair-raising arachnid—except for its appearance. A spider angioma is a small red or purple mark on the skin caused by dilated blood vessels near the skin’s surface. Spider angiomas get their name from the appearance they create on your skin, which looks like a red spider’s body and legs.

What is spider angioma?

A spider angioma appears as a small, red lesion or dot on the skin, surrounded by thin red lines. Spider angiomas resemble a red spider, thus, their name. The good news (especially for those who do not like spiders and bugs!) is that spiders do not cause spider angiomas—there are no spiders in or on your body. A spider angioma is simply called a spider angioma because the mark on your skin resembles a red spider. 

A spider angioma is caused by tiny blood vessels called capillaries near the skin that dilate (widen). Unlike many skin conditions, spider angiomas do not cause itching or irritation.

You may hear a spider angioma called:

• Spider naevus
• Spider nevi
• Nevus araneus
• Spider naevi
• Spider telangiectasia

What causes spider angiomas?

Spider angiomas are common. They are thought to affect about 38% of healthy children at some point in their childhood and almost 60% of pregnant women.

Spider angiomas may appear on the skin’s surface when blood vessels dilate or widen. This happens when muscles restrict blood flow in the arteriole, a small tube that branches off the arteries (a major blood vessel) and leads to capillaries (small, thin blood vessels). 

Spider angiomas can affect anyone, including healthy adults and young children, but are more common in:

• People with certain conditions, including hepatitis (inflammation of the liver) or liver cirrhosis (chronic liver damage which leads to scarring and liver failure, often caused by hepatitis or excess alcohol consumption)
• People with rheumatoid arthritis
• Pregnant women
• Children
• Young adults
• Individuals who are assigned female at birth
• Individuals who take an oral contraceptive pill (birth control pill)
• People who are malnourished

Spider angioma symptoms

Although spider angiomas can appear anywhere on the skin, they are most common on the arms, fingers, face, legs, neck, and upper chest or trunk. They are most noticeable on the face.

Symptoms of spider angiomas include:

• A flat (or slightly raised) red or purple dot on the skin that may resemble a pimple
• The dot has red or purple lines extending from the center that resemble spider legs
• The dot is less than ¼ of an inch in diameter
• The entire mark (dot and lines) disappears with the application of pressure on the central red spot and reappears when you remove your finger 
• Spider angiomas do not cause pain
• Spider angiomas may bleed a little bit if injured

Spider angioma treatment

If the spider angioma is due to an underlying condition, the healthcare professional will recommend treating the cause when possible. 

The actual spider angioma, however, does not require treatment in most cases. Some healthcare providers will perform fine-needle electrocautery (burning) or laser therapy to the site if treatment is desired or needed. These treatments are often successful but may be associated with scarring—and the spider angiomas may return.

Spider angiomas may disappear:

• In children after puberty
• In pregnant women after giving birth
• In women who take birth control pills after they stop taking the medicine
• In patients with cirrhosis after they have a liver transplant 

In adults, if untreated, spider angiomas tend to stay. Consult your healthcare professional for more information and questions about treatment.

How to prevent spider angiomas

There is no known advice on preventing spider angiomas. Results of clinical studies suggest that spider angiomas are related to levels of the hormone estrogen in your body. When estrogen levels increase during puberty and pregnancy, spider angiomas may increase. When estrogen levels are lower, spider angiomas may decrease or even disappear. 

Experts recommend maintaining good care of your health, especially if you have a medical condition such as chronic liver disease or a thyroid condition. If spider angiomas are a concern, you can discuss prevention tips with your physician. 

Diagnosis and when to see a doctor

A spider angioma can be clinically diagnosed based on its spider-like appearance. Some people may need a skin biopsy to rule out skin cancer and other conditions. 

Your healthcare provider may order additional tests if you have several spider angiomas or recurring spider angiomas. These tests may check for liver and thyroid function or other conditions that could cause spider angiomas. 

Consult your healthcare provider if you have a new spider angioma, especially if you have more than one, so they can check for other medical conditions.