Spider Nevus: Symptoms, Cause, Risk factors, Diagnosis, Treatment and Prevention

Updated: August 1, 2018

Spider nevus, also known as spider veins is a collection of small, dilated arterioles or blood vessels clustered very close to the surface of the skin. The cluster of vessels is web like, with a central spot and radiating vessels. It is also known as spider angioma, nevus araneus or vascular spider. It can be caused by injuries, sun exposure, hormonal changes, or liver disease, but often the cause is unknown.
The nevi are not a medical concern in most of the cases. But if they cause discomfort, the vessel clusters can be treated or removed. This can be done by use of compression stockings, chemical injections, and laser treatments.

Symptoms of Spider Nevus:

The only symptom is the appearance of the vessel cluster. There may be a red dot in the center of a cluster of thin vessels, but this is not always the case. The thin vessels form a web like shape and are red, blue, or purple in color. They will disappear when you apply pressure and then reappear as blood is flowing back into the vessels.
Spider nevi can occur anywhere on the body, but are most common on sun exposed areas such as the face, neck, and legs. Some people may experience aching or burning in the area of the vessel cluster. Most commonly this pain occurs when the vessels are in the legs, and after a long period of standing.
If you don't have any other symptoms or health conditions, these are usually not cause for concern. But if you have a spider nevus and feel weak, unusually tired, or bloated, or if your skin or eyes appear yellow, you should see your doctor. You should also see your doctor if you have multiple clusters of spider vessels, as this could be the underlying cause of liver problems. You can wait until your regular checkup to show the nevus to your doctor if you do not have any symptoms of illness.

Cause of Spider Nevus:

The exact cause of spider nervus is unknown. However, there are various factors that may result in spider nevi. These factors include:

• exposure to the sun
• injury
• changes in hormone levels
• underlying illnesses, such as liver disease

If there is presence of more than one spider nervus, that is a common sign of liver disease. People with liver disease often have multiple vessel clusters at a time.
Usually it occurs when you have increased level of estrogen in your system. This is the case with chronic liver disease or during pregnancy. Spider nevus is more common in people with alcohol related liver cirrhosis than in those with cirrhosis not related to alcohol.

Risk factors for Spider Nevus:

There are several factors that can put you at a higher risk of spider nervus. These include:

• Age: The older you are, the more likely you are to get spider nevi. Aging may cause the valves in your blood vessels to weaken.
• Hormonal changes: Going through puberty, pregnancy, and menopause, as well as taking hormonal contraceptives, may lead to spider nevi as the estrogen level could increase in all of these cases.
• Sun exposure: Being in the sun, especially if your skin is fair, can cause spider nevi to form on your face.
• Family history: Weak vessel valves may run in families, so if members of your family have spider nevi, you are more likely to get them as well.
• Obesity: Excess weight can put pressure on your blood vessels causing spider nervus.
• Sitting or standing for long periods of time: Being immobile can prevent the healthy circulation of blood.

Diagnosis of Spider Nevus:

Simply by looking at the appearance of the skin in question, your doctor will most likely be able to tell you if you have spider nevi. A skin biopsy may also be required to confirm the diagnosis. Diagnosing the underlying cause and ruling out certain conditions that may have produced the vessel clusters are more important.
Your doctor will also ask you about the below things that may help him diagnosing the cause.

Alcohol consumption:

Because alcohol abuse can lead to liver disease, it is important to know about your alcohol consumption. Spider nevi may be a sign of liver disease. A sample of your blood will be tested if liver problems are suspected.
The liver has many functions, such as detoxifying the blood, helping to digest food, and producing proteins that help the blood to clot. Liver disease testing, also called a liver panel, involves taking blood samples to test for the enzymes and proteins produced and excreted by the liver. Increased or decreased levels of these substances, as well as the presence of certain types, can signal liver disease.

Hormone supplements and any other medications:

These can increase the level of estrogen in your body which can lead to formation of spider nevi.

Treatments for Spider Nevus:

If spider nevi are not causing uncomfortable burning or itching and are not related to liver disease, then spider vessels are not harmful and do not require any treatment. However, if they cause any kind of discomfort, or if you choose to have them treated for cosmetic purposes, there are several choices.
One of the choice is laser treatment. In this treatment lasers aimed at the spider nevus can eventually cause it to fade and disappear. The laser and the heat it emits may cause some pain or discomfort. But this should go away as soon as the laser is removed. Two to five treatments are typically needed to completely fade the spider nevus.

Prevention of Spider Nevus:

There is no way to prevent spider nevus if the cause is family history and genetics. However you may prevent new spider nevi from forming by:

• avoiding hormone therapy
• wearing sunscreen on those areas most commonly affected, including the face, neck, and legs
• controlling your alcohol consumption
• treating liver disease if present