Everyone is familiar with birthmarks, yet some have a birthmark that produces hair. That is more typically called a hairy birthmark, but medically it is most frequently a congenital melanocytic nevus (CMN). Though they will at times cause cosmetic concern, in general they are benign, though in some cases, medical follow-up is required.

What Is a Hairy Birthmark?

A hairy birthmark is an abnormal discoloration of the skin that is darker than the rest of the surrounding tissue and contains visible hair upon it. The marks are formed during fetal development when there is a surplus of melanocytes (pigment cells) in the skin.

Hair on the spots can occur because the spot may also contain more hair follicles than normal. Sizes vary widely, to small freckles or large spots over large parts of the body.

Why Do They Occur?

Hairy birthmarks, also known as congenital hairy nevi, occur due to localized genetic mutations that cause an overgrowth of pigment-producing cells (melanocytes), and sometimes hair-forming cells, during fetal development.

Hairy birthmarks do not occur because of something the mother did during pregnancy. They occur due to a change in growth of skin cells when the baby is in the uterus. Genetics may be involved, but most of the time, they occur at random.

Are Hairy Birthmarks Dangerous?

Small congenital nevi are typically harmless and never cause any trouble except for cosmetic distress, but:

Larger or giant birthmarks are slightly more likely to have melanoma, a skin cancer.

The chance of this is determined by the size and where the birthmark is.

Other signs to look for are:

• Sudden thickening or growth

• Color change

• Itching, pain, or bleeding

If these happen, it is best to visit a dermatologist as soon as possible.

When to See a Doctor

Even if the stable birthmark is observed, it must be examined by a dermatologist at least once. Professional consultation helps to determine whether continued surveillance is needed. Children with very large or multiple congenital nevi may also be referred to specialists for more close monitoring.

Treatment and Management

All hairy birthmarks do not need treatment. They are decided on the basis of size, appearance, and preference:

• Observation: Follow-up skin examinations by a doctor and home surveillance.

• Surgical removal: Occasionally used for large or high-risk lesions, or for cosmetic reasons.

• Laser therapy: May reduce pigmentation but typically does not remove the lesion.

Treatment is highly individualized one size does not fit all.

Living With a Hairy Birthmark

For many people, a hairy birthmark is simply part of who they are. While it may at times affect confidence, especially if it is visible, it rarely causes major health problems. Support from family members, friends, and medical professionals can be of massive influence on how a person feels about their skin.

Key Takeaway

A hairy birthmark, the most common being a congenital melanocytic nevus, is usually harmless but warrants medical attention if it’s large or evolving. Routine skin monitoring and professional assessment ensure that any potential risks are identified early.

If you or your child has an alarming birthmark, the best course of action is to find a dermatologist.