What Causes It?
Ultraviolet (UV) radiation exposure - From the sun or tanning beds, which can damage DNA in skin cells.
Fair skin - Less melanin means less protection from UV radiation.
History of sunburn - Severe, blistering sunburns, especially in childhood or adolescence.
Excessive UV exposure - Living close to the equator or at high altitudes.
Many moles or unusual moles - Having more than 50 ordinary moles or any atypical moles (dysplastic nevi).
Family history of melanoma - Having one or more close relatives with melanoma.
Personal history of melanoma - Increases risk of developing another melanoma.
Weakened immune system - Due to disease, organ transplant, or certain medications.
Age - Risk increases with age, though melanoma is one of the most common cancers in young adults.
Xeroderma pigmentosum - A rare genetic disorder that reduces the skin's ability to repair DNA damage.
Previous radiation treatment - For other cancers can increase risk of melanoma in the treated area.
Signs & Symptoms
Changes in an existing mole - Size, shape, color, or elevation.
New skin growth - Especially one that looks unusual or changes over time.
A mole that follows the ABCDE rule:
A - Asymmetry: One half doesn't match the other half.
B - Border: Irregular, ragged, notched, or blurred edges.
C - Color: Uneven coloration, multiple colors (tan, brown, black, red, white, or blue).
D - Diameter: Larger than 6 millimeters (about the size of a pencil eraser).
E - Evolving: Changes in size, shape, color, or elevation; new symptoms like bleeding, itching, or crusting.
A sore that doesn't heal - Or that heals and then returns.
Spread of pigment from the border of a spot into surrounding skin.
Redness or swelling beyond the border of a mole.
Change in sensation - Itchiness, tenderness, or pain in a skin lesion.
Changes in the surface - Scaliness, oozing, bleeding, or the appearance of a bump or nodule.