What is Hairy Nevus Syndrome?

Posted on June 7, 2012

A hairy nevus is a type of mole that is present at birth. These moles do not usually run in families, meaning they are not inherited. Some of them can be very pale at birth and then become more visible shortly after birth.

Hairy nevi are generally divided into categories based on their size: small, medium and large. They can appear on virtually any place on the body and about 50 percent of hairy nevi will develop coarse surface hairs.  Although most hairy nevi are benign (harmless), they can occasionally turn into malignant melanoma (cancerous).  That’s why it’s important to have any birthmarks examined by a physician. Report any changes in the birthmark to your health care provider, including:

  • Bleeding
  • Color change
  • Inflammation
  • Itching
  • Open sore (ulceration)
  • Pain
  • Size change
  • Texture change

According to Nevus Outreach, Inc, small nevi are very common, occurring in one in every 75 people. Large congenital nevi are more rare and occur approximately once in every 20,000 births. Giant congenital nevi are thought to occur approximately once in every 500,000 births. For more information, visit www.nevus.org.

Diagnosis of a Hairy Nevus

Unlike regular moles, which often don’t start to appear until a child is a toddler or even older, hairy nevi moles are present at birth. A doctor will see the mark by doing a physical examination of the baby. A hairy nevus is also evaluated by looking at these characteristics:

Size in diameter

·         small (1.5 cm or smaller)

·         medium (1.5 – 2.0 cm)

·         large (20 cm or larger)


·         sharp

·         regular

·         irregular

·         blended with surrounding skin


·         textured

·         with or without hair


·         round

·         oval


·         single spot

·         multiple spots (fewer than 5 percent of patients have multiple spots)

Treatment for Hairy Nevus:

Shriners-Boston offers treatment for hairy nevi, and the treatment will vary depending on the size of the hairy nevus and whether it is benign or malignant.

The most common treatment for hairy nevi is surgical removal. Removal of small nevi is typically done in just one procedure. Removal of very large nevi may require multiple stages or placement of tissue expanders to create extra skin to cover the area where the nevi are removed. In cases where the hairy nevus is located on the nose, ears or eyelids, removal may include a skin graft from another part of the body.

Your child’s doctor will determine the best treatment for your child based on the size and location of the hairy nevus, as well as the age and medical condition of your child.


To learn more about skin treatment, or other types of treatment at Shriners-Boston, we encourage you to reach out by calling us at 617-722-3000.

If you’d like to support the children who receive treatment at Shriners-Boston, please consider making a donation to the hospital.

Posted in: Articles  |  Tagged: hairy nevus, birthmark, treating hairy nevus syndrome, hairy nevi  |  Bookmark the Permalink

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