Would you recognize the mole that doesn't belong?
Melanoma caught early is highly treatable — and the people who catch it early are usually the ones who knew what to look for. Learn the ABCDE warning signs in plain language, then walk one spot through a structured check and log it for a monthly re-look. This page teaches. It never diagnoses.
Skip the self-check and book an appointment now if…
- The spot bleeds or oozes without having been injured
- You have a sore that hasn't healed after 3–4 weeks
- It's growing or changing quickly — over weeks, not years
- There's a new dark line or streak in or under a nail, especially one spreading onto the surrounding skin
- A raised, firm bump keeps getting bigger, even if it's one even color
- A spot is persistently painful, itchy, or crusting and not settling down
Any of these means the checklist below is the wrong tool — go straight to a board-certified dermatologist (or your doctor, if that's faster to access). Our appointment prep tool can help you make that visit count.
The ABCDE signs, in plain language
Dermatologists use five letters to describe what tends to separate a worrying pigmented spot from an ordinary mole. None of them is proof of anything on its own — they're patterns worth noticing, and reasons to get a professional look.
Asymmetry
Picture folding the spot in half through its middle. Most harmless moles fold neatly — the two halves roughly mirror each other. A melanoma is often lopsided, with one half that simply doesn't match the other.
Border
Benign moles usually stop cleanly — a smooth, even, well-defined edge against the skin. Be more cautious about borders that look ragged, notched, or scalloped, or edges that blur and fade into the surrounding skin instead of ending crisply.
Color
A typical mole is one even shade of brown, edge to edge. The pattern to notice is a patchwork: browns, black, and tan mixed in one spot, or areas of red, white, or blue-grey inside the same lesion. Several colors in one spot deserve a professional opinion.
Diameter
Melanomas are often wider than about 6 mm — roughly a pencil-top eraser — by the time they're noticed, though they can absolutely be smaller. Size alone proves nothing; a spot that's getting bigger matters far more than one that's merely big.
Evolving
The most important letter. A spot that's changing — in size, shape, color, or height — or that starts to itch, bleed, or crust, has earned a dermatologist visit on that basis alone, even if every other letter looks fine. Stable over years is reassuring; changing over weeks or months is not.
The "ugly duckling" sign
Your moles tend to share a family resemblance — similar shades, similar sizes. The ugly duckling is the outlier: the one spot that's noticeably darker, bigger, or differently shaped than all its neighbors. That standout deserves a closer look even when no individual ABCDE letter is dramatic.
The exception worth knowing: EFG
Nodular melanoma — a fast-growing form — can pass every ABCDE test. It's often symmetric, a single even color (sometimes red, pink, or skin-toned rather than brown), and small when it starts. Its signature is different: Elevated above the skin, Firm to the touch, and Growing steadily for more than a few weeks. A raised, firm bump that keeps getting bigger belongs in front of a dermatologist regardless of how "normal" its color looks.
Walk one spot through the check
Pick a single spot — good light, up close, and use a mirror or a phone photo for awkward angles. Answer honestly; "not sure" is a perfectly good answer, and it's more useful than a guess. One spot at a time keeps you actually looking rather than skimming.
Saved checks are private to you — kept on this device, and backed up to your free account when you're signed in. Never sold or shared.
Your spot log
Re-check each saved spot about once a month. The E in ABCDE — change — only shows up if you look more than once.
Make the habit stick
Saved only on this device — and browsers erase site data. A history clear, a private window, or Safari's automatic deletion after seven days without a visit will take this log with it. The fix is a free Dermington account: it backs this up automatically and puts it on every device you sign in to — details in how storage works.
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- Surgical DermatologyNo, They Won't Just Burn It Off: Why Mole Removal Goes Through a MicroscopeYou want it gone in five minutes. Your dermatologist wants a specimen. That single disagreement is the entire safety architecture of the appointment — and a vaporised mole can never be diagnosed.
- Men's SkincareMale Skin Ages on a Cliff, and Fifty Is Roughly Where the Ground GoesWomen get a biological alarm bell at menopause. Men get a straight line down from their twenties, which is why so many arrive at fifty-five with thirty-five years of unopposed decline and no routine.
- Men's SkincareMen Die of Melanoma at Twice the Rate of Women. Most of That Gap Is a Looking Problem.Tumor biology explains a slice of it. The rest is where the lesion sits, who is willing to look at it, and how many months pass before anyone does.
How this self-check works
The ABCDE framework comes straight from the dermatology literature: the ABCD criteria — Asymmetry, Border, Color, Diameter — were published in 1985 as a teaching aid for spotting early melanoma, and E for Evolving was added in a 2004 JAMA revision after change proved to be one of the strongest warning signs of all. The "ugly duckling" sign, described in 1998, adds the common-sense observation that the mole worth examining is often the one that looks unlike all of a person's others. This tool teaches each sign in plain language, then asks you to answer them one by one for a single spot: looks fine, not sure, or matches the warning sign.
What it deliberately does not do is score, rank, or reassure. Any answer of "matches" points you to a board-certified dermatologist; any "not sure" suggests photographing the spot and showing it to a professional; even a fully clear run is only "nothing flagged today — re-check monthly," because self-checks miss things. Nodular and amelanotic melanomas in particular can look nothing like the classic picture. Saved spots stay private to you — on this device, and in your account if you have one — so you can re-run the check each month and notice change, which is the entire point of the habit.
This tool is educational and cannot diagnose, screen for, or rule out skin cancer. A harmless-looking result here is not an all-clear. Any new, changing, or worrying spot should be examined by a board-certified dermatologist, whatever this page shows.
Common questions
What does melanoma look like?
There is no single melanoma "look," which is exactly why the ABCDE framework exists. Classically it appears as a flat or slightly raised spot that is asymmetric, has ragged or blurred borders, shows several colors at once — browns, black, tan, sometimes red, white, or blue-grey — and is wider than about 6 mm. But melanomas can also be pink, skin-colored, or nail-based, and nodular melanomas can look like a plain firm bump. Change over time is the most reliable common thread.
What is the ABCDE rule for moles?
ABCDE is a memory aid dermatologists teach for the visual warning signs of melanoma: Asymmetry (one half unlike the other), Border (ragged, notched, or blurred edges), Color (more than one shade in the same spot), Diameter (wider than about 6 mm, a pencil eraser), and Evolving (any change in size, shape, color, height, or new itching, bleeding, or crusting). The ABCD criteria were published in 1985, and the E for Evolving was added in 2004 because change turned out to be one of the strongest signals of all.
When should I worry about a mole?
The spots that deserve prompt professional attention are the ones that are changing, bleeding without injury, refusing to heal, growing quickly, or standing out from every other mole you have. A single ABCDE feature on a stable, long-standing mole is far less concerning than a spot that is actively evolving. When in doubt, the answer is never to keep wondering — it is a short appointment with a board-certified dermatologist.
How often should I check my moles?
Once a month is the standard advice: a head-to-toe look in good light, using a mirror or a partner for your back, scalp, and other hard-to-see places. Monthly is frequent enough to catch change early but spaced enough that genuine change is visible between checks. Dated photos make the comparison far more reliable than memory — human recall of what a mole looked like six weeks ago is famously bad.
Can melanoma look like a normal mole?
Yes — and this is the most important limitation of any checklist, including this one. Nodular melanomas often fail every ABCDE test: they can be symmetric, uniform in color, even pink or skin-toned, and small when they start. Their giveaway is the EFG pattern — Elevated, Firm to the touch, and Growing steadily over weeks. Amelanotic melanomas have little or no pigment at all. This is why a self-check is a habit that supplements professional skin exams, never a substitute for them.