Melanoma
Also known as: Malignant Melanoma, Melanoma Skin Cancer, Melanoma Disease
The most dangerous skin cancer - but 99% survival when caught early. Learn the ABCDE signs.
What to look for
Side-by-side comparison
Normal mole
Round, even color, stable
Possible melanoma
Irregular, multi-color, changing
Melanoma develops in melanocytes, the cells that produce melanin and give your skin its color. While it accounts for only about 1% of skin cancers, it causes most of skin cancer deaths. The good news: when detected at stage I, the five-year survival rate exceeds 99%.
Around 70-80% of melanomas arise as entirely new growths on previously normal skin - not from existing moles. This is the reason monthly full-body self-examination is just as important as monitoring moles you already have. Any new spot that looks different from your other spots deserves attention.
The ABCDE rule is the gold standard for self-screening: Asymmetry (one half doesn't match the other), Border (edges are irregular or blurred), Color (multiple colors or uneven distribution), Diameter (larger than 6mm, roughly pencil eraser size), and Evolution (any change in size, shape, color, or symptoms). Evolution is considered the single most important criterion - any changing lesion should be evaluated promptly.
Melanoma can develop anywhere on the body, including areas that rarely see sunlight: the soles of feet, under fingernails, inside the mouth, and even on the eye. In people with darker skin tones, melanoma most commonly appears on the palms, soles, and under the nails.
Risk increases with UV exposure, particularly blistering sunburns before age 18. People with fair skin, more than 50 moles, a family history of melanoma, or a weakened immune system face higher risk. However, melanoma can affect anyone regardless of skin color or sun exposure history.
Quick self-check
Does this look like melanoma? Answer 2 questions.
Has this spot changed in size, shape, or color recently?
Does it have multiple colors or irregular, blurred edges?
The ABCDE Rule — Visual Guide
The screening method dermatologists recommend for self-examination.
Asymmetry
One half does not match the other half
Normal
Both halves match
Warning
Halves don't match
Border
Edges are irregular, ragged, or blurred
Normal
Smooth, well-defined edge
Warning
Ragged, blurred edges
Color
Multiple colors or uneven color distribution
Normal
One uniform color
Warning
5+ colors mixed
Diameter
Larger than 6mm — about the size of a pencil eraser
Normal
Under 6mm
Warning
Over 6mm (pencil eraser)
Evolution
Any change in size, shape, color, or symptoms over time
Normal
No change over 12 months
Warning
Grew, darkened, irregular
Most important: Evolution (E) is considered the single most critical criterion. Any mole that is changing — in size, shape, color, or producing new symptoms like itching or bleeding — should be evaluated by a dermatologist regardless of other features. This guide is for screening only.
Risk factors
- Fair skin, light eyes, red or blond hair (Fitzpatrick types I-II)
- History of blistering sunburns, especially before age 18
- More than 50 ordinary moles on the body
- One or more dysplastic (atypical) nevi
- Family history of melanoma in a first-degree relative
- Personal history of any previous skin cancer
- Weakened immune system (organ transplant, HIV, immunosuppressive drugs)
- Excessive UV exposure from sun or tanning beds
- Living at high altitude or near the equator
When to see a dermatologist
- ⚠A new mole or spot that looks different from your other moles (the ugly duckling sign)
- ⚠Any mole that changes in size, shape, color, or elevation
- ⚠A mole that itches, bleeds, crusts, or becomes painful without injury
- ⚠A dark streak under a fingernail or toenail not caused by trauma
- ⚠A sore anywhere on the body that does not heal within three weeks
Often confused with
Not sure if this is melanoma? Compare:
Want a more detailed check?
Our full ABCDE checker evaluates 5 clinical criteria in 30 seconds.
Full ABCDE check →Frequently asked questions
Can melanoma appear suddenly without a pre-existing mole?
Yes. Roughly 70-80% of melanomas develop as brand new growths on normal-looking skin rather than from existing moles. This is the reason checking for new spots during monthly self-exams is just as important as watching existing moles.
Is melanoma always dark or black?
No. Amelanotic melanoma contains little or no pigment and can appear pink, red, purple, or even skin-colored. This type is less common but more easily missed. The Evolution criterion of ABCDE (any changing lesion) is the most reliable way to catch these.
How quickly does melanoma spread?
Growth rate varies considerably. Superficial spreading melanoma may grow slowly over months to years. Nodular melanoma can progress rapidly in weeks. This unpredictability is why dermatologists urge prompt evaluation of any suspicious or changing lesion.
Can people with dark skin get melanoma?
Yes. While melanoma is more common in fair-skinned individuals, it can affect people of any skin color. In darker skin tones, melanoma most often appears on the palms, soles of feet, and under fingernails or toenails. Bob Marley died from acral melanoma under his toenail.
At what age should I start checking my skin?
There is no minimum age. Melanoma can occur in teenagers and young adults - it is one of the most common cancers in people under 30. Monthly self-exams should become a lifelong habit, starting in your teens.
Can AI mole-checking apps detect melanoma?
Research shows that leading AI screening tools achieve 85-95% sensitivity in detecting suspicious lesions, comparable to some non-specialist physicians. They are valuable as screening aids that can flag concerning spots for professional evaluation, but they are not diagnostic devices and should never replace a dermatologist examination.
Related conditions
Dysplastic Nevus
Atypical moles with irregular features. The single strongest visual risk marker for melanoma.
Lentigo Maligna
The earliest stage of a specific melanoma type. A slowly expanding flat brown patch on sun-damaged facial skin.
Common Nevus
Normal moles - clusters of pigment cells. Usually harmless, but monthly monitoring for changes is essential.
Basal Cell Carcinoma
The most common cancer in humans. Slow-growing, rarely spreads, but can cause serious tissue damage if untreated.