What does it look like?
The lesion consists of a central red elevation (the ‘body of the spider’), usually about the size of a pinhead. Fine blood vessels radiate outward from this center (the ‘legs of the spider’).
- The redness can be blanched: pressing on the spot temporarily forces the blood out of the vessels. When released, the vessels refill immediately.
- Spider naevi most commonly appear on the face.
Who gets it?
- Spider naevi can occur at any age but are most commonly seen in children and young adults.
- They frequently occur in pregnant women.
- In other adults, they are less common but may sometimes be associated with underlying conditions such as liver cirrhosis.
How does it form?
A spider naevus forms due to the local dilation of a small blood vessel in the skin. The exact cause of this dilation is unknown.
How is it diagnosed?
The diagnosis is straightforward and based on the characteristic appearance of the lesion. Spider naevi are easily identifiable with the naked eye.
How is it treated?
While spider naevi are completely harmless, treatment is often requested for cosmetic reasons. Spontaneous resolution may occur in young children or pregnant women. If treatment is desired, there are two main options, depending on the size of the lesion:
- Coagulation:
- Suitable for spider naevi with a larger central vessel.
- A small needle is inserted into the central vessel, and an electric current is used to cauterize it.
- The remaining radiating vessels can then be treated with a vascular laser.
- Note: coagulation may leave a small scar.
- Laser treatment:
- For smaller spider naevi, vascular laser treatment is the best option.
- Laser treatment generally does not cause scarring.
Both methods are effective, with laser treatment preferred for smaller lesions or cosmetically sensitive areas.
photo: spider naevus near the lower eyelid.