What Is Spider Angioma?

  • Stephanie Leadbitter MSc Cancer Biology & Radiotherapy Physics, BSc (Hons) Biomedical Science, University of Manchester, UK

Defining spider angioma 

A spider angioma, also known as a ‘spider naevi’ or ‘spider telangiectasia’, is defined as the appearance of small, red, thread-like markings just under the surface of the skin.1 These peculiar markings are caused by the enlargement of small blood vessels beneath the surface of the skin.1 They are composed of a small, circular centre, which is the result of dilatation (enlargement) of a structure known as an ‘arteriole’.1 Arterioles are structures which connect our large arteries with smaller blood vessels, known as capillaries. These capillaries can be observed spreading out from the arteriole, giving the appearance of thin, wispy, ‘spider-legs’. It is thus that these peculiar markings are named ‘spider’ due to their general appearance resembling that of a spider. Patients may also notice areas of redness around these markings and may notice either one or many of these on their bodies. 

What causes spider angioma to form? 

The exact causes of spider angioma remain unknown and have remained a topic of great debate for some time. At its most fundamental level, dilatation of the arteriole (the spider’s ‘body’) is caused by dysfunction of the muscles surrounding the ends of the vessel.1 These are known as the ‘sphincter muscles’ and are responsible for allowing the enlargement or enclosement of the ends of these vessels. In the case of Spider Angioma, there is dysfunction within these muscles, which results in their relaxation and loosening of the ends of the arterioles.1 As such, we see this dilatation present as the red blot central to the ‘spider’s body’.

What causes this dysfunction, however, remains to be properly established. Studies have indicated a number of potential causes, such as associations between large intakes of alcohol and the development of this condition.1 Furthermore, it is also thought that high levels of estrogen can also contribute to the formation of spider angioma.1 Estrogen plays a critical role in the normal development of the sexual and reproductive systems within that assigned female at birth (AFAB).2 Despite this, estrogen also affects numerous other tissues throughout the body, including the heart and blood vessels.2 This is why it is thought to play a role in the development of spider angioma. Another theory is that any impairment in the liver, and thus steroid hormone production, also plays a role in the formation of spider angioma.1 It is through these proposed influences that the following people are predisposed to the development of spider angioma:1 

Are spider angiomas always a cause for concern? 

While we have discussed the groups of patients most at risk of developing spider angiomas, you may be wondering whether or not these are indicative of cause for concern. It is important to note that pregnancy, puberty, and childhood can indeed be normal and do not warrant any major concern.1 Thought to be due to the influence of fluctuating hormonal levels, the development of spider angioma can be normal during these times. For example, studies have shown spider angioma to have a general prevalence of 38% among healthy children and 60% among those who are pregnant.1 Usually, these will often disappear following development into adolescence and the termination of pregnancy. 

However, if these happen to develop in patients with liver impairment, these are often signs as a poor indicator of patient prognosis. In those patients with alcoholic hepatitis, the presence of spider angioma is indicative of poorer outcome, with the number of spider angioma also being indicative of the extent of fibrosis in those with liver cirrhosis.1 Additionally, the presence of a singular spider angioma is often not cause for concern. However, if you notice more numerous across your body, these can be indicative of the causes listed above.3 

Symptoms and appearances of spider angioma 

As we have previously discussed, spider angiomas are due to dilatation of the blood vessels beneath the surface of the skin.1 These blood vessels are known as the arterioles (the ‘body’ of the spider) and the capillaries (the ‘legs’ of the spider). The capillaries will continue to thin as they travel from the arteriole before disappearing completely.1 Spider angiomas are also characterized by the following features:3 

  • Appear as flat or slightly raised red to purple dot on the surface of the skin. The centre of these may be similar in appearance to a pimple.
  • The central dot has a number of lines extending from it (the ‘legs’ of the spider) 
  • The dot is usually less than 0.5cm in diameter. 
  • When pressure is applied to the dot, it completely disappears. It will reappear when pressure is removed. 
  • They are painless.
  • They may bleed lightly if the surface of these dots is pierced. 

Spider angiomas are also most commonly located in a number of areas throughout the body. They are said to follow the distribution of a blood vessel known as the superior vena cava and are found in these common places (in an adult):1 

  • The face 
  • The neck 
  • The upper chest 
  • The arms 

In children, the most common places for spider angiomas to develop are:1

  • The upper extremities 
  • The backs of the hands 
  • On fingers 

It is also important to note that spider angioma can sometimes be seen inside the mouth, so patients should remain vigilant when checking for their presence.1 Furthermore, spider angioma can also be found on the torso and abdominal area in cases of severe liver disease.1 They may also be found in the legs and feet.3 

How are spider angioma diagnosed? 

Your healthcare provider may first ask you a series of questions pertaining to the length of time you have had them and any other symptoms you may be experiencing. This line of questioning is what underpins the ‘medical history’. Following this, your healthcare provider will then assess the spider angioma and will take note of its colour, size, shape and other characteristics. In doing so, they will be able to confirm the diagnosis of spider angioma and exclude other important diagnoses. 

Your healthcare provider may also perform a quick, specialized test to confirm their suspicions of spider angioma. This involves applying pressure over the spider angioma with the use of a glass slide (diascopy).1 This will cause the spider angioma to go pale (known as pallor) before its color returns following removal of the diascopy.1 This characteristic is unique to spider angiomas and, therefore, confirms the diagnosis of spider angioma.1

How are spider angioma treated?

In those patients who develop spider angioma due to underlying health conditions, treatment is aimed at first tackling the underlying condition. Through treatment of this, patients will often experience resolution. However, for those wishing to treat spider angioma for cosmetic purposes, the following treatments are available: 

Are there any complications associated with treatment? 

It is important to note that spider angiomas often return following treatment so frequent treatment may be required.1 It is also important to follow any recommendations regarding skin care post-procedure. Following these guidelines will prevent any scarring from developing and will allow proper wound healing. 


Spider angiomas are characterized by a central purple/red dot and numerous thread-like structures that radiate outwards from it. This pattern of distribution is what affords it its ‘spider’ name. These markings are often flat and painless and may sometimes bleed if they are injured slightly. Common in both normal development and a number of diseases, singular spider angiomas are often not a cause for concern. However, when numerous are seen, patients should seek medical attention as this may indicate an underlying disease. They are most commonly seen in cases of liver impairment and are often a sign of poor prognosis in those with alcoholic hepatitis. Your healthcare provider will often ask a series of questions relating to the spider angioma before performing an examination and, in special cases, a special test. This will allow your healthcare provider to confirm a diagnosis. Treatment is often targeted at first addressing the underlying causes, with cosmetic treatments aimed at laser therapy and electrodesiccation.  


  1. Samant H, Kothadia JP. Spider Angioma. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 [cited 2023 Oct 19]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK507818/.
  2. Estrogen’s Effects on the Female Body [Internet]. 2022 [cited 2023 Oct 19]. Available from: https://www.hopkinsmedicine.org/health/conditions-and-diseases/estrogens-effects-on-the-female-body.
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Morgan Keogh

MBBS, Medicine, King's College London, UK

I am a fourth year Medical Student at Kings College London, currently intercalating in a BSc in Cardiovascular Medicine. I have a strong interest in Cardiology, Acute Internal Medicine and Critical Care. I have also undertaken a research project within the field of Cardiology whereby I explored the efficacy of a novel therapeutic test at detecting correlations between established clinical characteristics and salt-sensitive hypertension. I have broad experience with both the clinical and theoretical aspects of medicine, having engaged with a wide array of medical specialities throughout my training. I am currently acting as a radiology representative within the Breast Medicine Society and have experience with tutoring at both GCSE and A-level. I am also working closely alongside medical education platforms to ensure the delivery of content applicable to the learning of future doctors.

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