Blue Nevus
Also known as: Blue Mole, Blue Beauty Mark, Purple Nevus, Blue Freckle, Bluish Mole
A blue or blue-black mole caused by deep pigment cells. Stable and benign - but can mimic melanoma.
What to look for
Side-by-side comparison
Normal skin
No blue-tinted spots
Blue nevus
Blue-black, deep pigment
A blue nevus is a benign melanocytic mole that appears distinctly blue, blue-gray, or blue-black because the melanocytes are located deep within the dermis. The blue color is an optical effect called the Tyndall effect - the same phenomenon that makes veins appear blue through skin.
Blue nevi are usually small (under 1cm), well-circumscribed, dome-shaped, and uniformly colored. They are most common on the hands, feet, face, and scalp. They typically appear in childhood or young adulthood and remain stable.
The clinical concern is that blue nevi can resemble nodular melanoma or blue-black melanoma. A key distinguishing feature is stability - a blue nevus that has been present and unchanged for years is almost certainly benign. Any blue-black lesion that is new, changing, or growing should be evaluated promptly.
Malignant blue nevus is a recognized but extremely rare entity, occurring almost exclusively in large congenital blue nevi. Standard small blue nevi have negligible malignant potential.
People often describe blue nevi as a "blue dot on skin," "blue beauty mark," or "blue freckle." Some appear more purple or blue-green depending on skin tone and depth of the melanocytes. All these color variations fall under the same diagnosis. A single, stable, small blue spot that has been present for years is almost always a blue nevus and nothing to worry about.
Quick self-check
Does this look like blue nevus? Answer 2 questions.
Is the spot distinctly blue or blue-black in color?
Has it been stable and unchanged for years?
Risk factors
- No specific risk factors - can occur in anyone
- More common in women
When to see a dermatologist
- ⚠A new blue or blue-black spot, especially if growing
- ⚠Any change in a previously stable blue nevus
- ⚠A blue-black lesion larger than 1cm
Often confused with
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Full ABCDE check →Frequently asked questions
Why does a blue nevus look blue?
The melanocytes are located deep in the dermis rather than near the surface. Light passing through the skin is scattered in a way that makes the pigment appear blue - the same optical effect (Tyndall effect) that makes veins look blue.
Can a blue nevus become melanoma?
Standard small blue nevi have negligible malignant potential. Malignant blue nevus is extremely rare and occurs almost exclusively in large congenital blue nevi. A stable, small blue nevus does not need removal.
I found a blue dot on my skin - should I worry?
A single small blue dot that is stable and well-defined is most likely a blue nevus. If it appeared recently, is growing, or has irregular borders, see a dermatologist to rule out melanoma.
What is the difference between a blue mole and melanoma?
Blue nevi are small, well-defined, uniform in color, and stable over years. Melanoma tends to be asymmetric, have irregular borders, multiple colors, and change over time. Any blue-black spot that is new or changing needs evaluation.
Can a blue nevus be purple or green?
Yes. Depending on skin tone and the depth of melanocytes, a blue nevus can appear blue-gray, blue-black, purple, or blue-green. These are all normal color variations of the same benign lesion.
Related conditions
Melanoma
The most dangerous skin cancer - but 99% survival when caught early. Learn the ABCDE signs.
Common Nevus
Normal moles - clusters of pigment cells. Usually harmless, but monthly monitoring for changes is essential.
Spitz Nevus
A dome-shaped pink or brown mole common in children. Can closely resemble melanoma under the microscope - often excised for certainty.
Dermatofibroma
Firm, small brown bump - usually on the legs. Harmless. The dimple sign is its signature feature.