Understanding Skin Moles: Causes, Types & When to Worry

Moles (nevi) are clusters of melanocytes (pigment cells). Most appear in childhood and adolescence; adults typically have 10–40. While usually benign, some can become melanoma.

Types of Moles

• Common Acquired Nevi: Small, uniform, tan/brown, symmetric. Appear in first 30 years.
• Congenital Nevi: Present at birth. Large (>20 cm) carry higher melanoma risk.
• Atypical (Dysplastic) Nevi: Larger, irregular borders, color variation. Marker for increased melanoma risk, especially with family history.
• Spitz Nevi: Pink, dome-shaped; usually benign but can mimic melanoma.
• Blue Nevi: Deep dermal pigment, blue-gray. Usually benign.

ABCDE Rule for Melanoma Warning Signs

• Asymmetry: Halves don't match.
• Border: Irregular, scalloped, blurred.
• Color: Varied shades (brown, black, red, white, blue).
• Diameter: >6 mm (pencil eraser), but can be smaller.
• Evolving: Changing size, shape, color, elevation, or new symptoms (itch, bleed).

Additional Warning Signs

• "Ugly duckling" mole—looks different from all others.
• New mole after age 30–35.
• Bleeding, crusting, or non-healing.

Monitoring & Prevention

• Monthly self-exam (full body, including scalp, soles, nails).
• Annual dermatologist skin check (more often if high risk).
• Sun protection: broad-spectrum SPF 30+, clothing, shade.
• Avoid tanning beds.

Early melanoma is highly curable. When in doubt, get it checked.