Melanoma is the skin cancer most likely to spread, yet in its early stages it often looks like an ordinary mole. Learning the main melanoma warning signs gives you a way to notice change before it becomes serious. The ABCDE rule is the simplest memory aid for this. Each letter describes a feature that doctors look for when they decide if a mole needs a closer look.The rule is not a diagnosis. It is a prompt to see a GP, who can examine the spot with proper tools. Many moles that match one letter turn out to be harmless. The value of the rule lies in making sure the worrying ones are not ignored.
Where the rule comes from
The ABCDE rule grew out of clinical research into the visible features of early melanoma. Cancer Council NSW describes the ABCD and EFG rules as tools doctors use to look for the characteristics of melanoma. The public can use the same letters as a guide for self-checks. The E was added later, because change over time proved to be one of the most useful signs.The letters are most helpful when you treat them as a set of questions. When you look at a mole, you ask how it compares with a normal one on each feature. A mole that raises concern on even one letter is worth showing to a GP. A mole that raises concern on several letters needs attention soon.
Reading the five letters
A is for asymmetry:
A normal mole is usually symmetrical. If you drew a line through the middle, the two halves would look much the same. A melanoma often grows unevenly, so one half looks different from the other in shape or colour. Asymmetry on its own is not proof of cancer, but it is a reason to have the spot checked.
B is for border:
Harmless moles tend to have a smooth, even edge. The border of a melanoma is often irregular, with notches or a blurred edge that fades into the surrounding skin. Some people describe it as looking like a coastline on a map instead of a neat circle. A ragged border deserves a GP's attention, especially on a mole that is new.
C is for colour:
Most ordinary moles are a single shade of brown. A melanoma may show several colours at once, such as different browns mixed with black. Patches of blue or red within a mole can also be a warning sign. Colour variation within one spot matters more than how dark the spot is overall.
D is for diameter:
Melanomas are often wider than about 6 millimetres, roughly the size of a pencil rubber. Size alone is a weak signal, because many large moles are harmless. Melanomas can also be found when they are much smaller than 6 millimetres. Treat the diameter guide as one clue among several, not as a fixed threshold.
E is for evolving:
Change is the most important letter in the rule. DermNet explains that a harmless mole usually stays stable, while a melanoma changes in size or colour over months or years. Change can also mean a mole that starts to itch or bleed. DermNet also notes that melanoma accounts for less than 3 per cent of all changing skin lesions. Most changing spots are harmless, but only a doctor can tell which ones are not.
When melanoma does not follow the rules
Some melanomas do not match the ABCDE pattern at all. Cancer Council NSW notes that nodular and desmoplastic melanomas do not fit the ABCD guidelines. Nodular melanoma is a fast-growing type that forms a lump instead of a flat, spreading patch. It is often symmetrical and a single colour, so it can look harmless at first glance.
Doctors use a second memory aid, EFG, to identify these lumps. The letters describe a spot that is raised above the skin and firm to the touch. It also keeps growing steadily for more than a month. A new lump with these features needs prompt assessment, even if it looks nothing like a typical mole.Some melanomas have little or no pigment. These amelanotic melanomas may look pink or red and can be mistaken for a pimple or a small scar. Because they lack the usual dark colour, they are easy to dismiss. Any pink lump that keeps growing or will not heal should be seen by a GP.
The odd mole out
Comparing moles against each other is one of the most practical self-check methods. DermNet notes that most people have a signature pattern, where their moles look alike. A melanoma tends to look different from the rest. Doctors call this the "ugly duckling" sign, and a spot that stands out should be treated as suspicious even if it meets none of the ABCDE criteria.
Cancer Council NSW makes a similar point. In people with many moles, a melanoma usually stands out from the others. This makes the ugly duckling sign useful for people who find the full ABCDE rule hard to apply across dozens of spots. It also works well for a partner who helps check areas you cannot see.
Spots that are usually harmless
Not every dark or unusual spot is a mole, and most are not melanoma. Freckles are flat and light brown, and they often fade in winter. Seborrhoeic keratoses are waxy, raised growths that look stuck on to the skin. They become common after middle age and can be dark, but they are not cancerous.
Other common spots can also cause worry. Small red dots called cherry angiomas often appear on the trunk with age. A dermatofibroma is a firm bump, often on the legs, that dimples inward when you pinch the skin beside it. These spots are harmless, but a GP should confirm this if you are unsure.
The point is not to diagnose these spots yourself. It is to understand that a new spot is often benign, so a check does not have to be frightening. What matters is that a doctor looks at any spot that is new or changing.
Melanoma in places you might not look
Melanoma can start anywhere on the skin, including areas that rarely see the sun. The scalp is easy to overlook, especially under thick hair. The soles of the feet and the skin between the toes are also common blind spots. Men often develop melanoma on the back, while women more often develop it on the lower legs.
Many melanomas appear as a completely new spot on normal skin. This means you cannot rely only on watching the moles you already have. A new spot in adult life, particularly after the age of 40, deserves attention. Show it to a GP even if it matches none of the ABCDE letters.
Why acting quickly matters
The stage of a melanoma at diagnosis has a strong effect on survival. Cancer Australia data on survival by stage shows that five-year relative survival for Stage 1 melanoma is at least 98 per cent. For melanoma diagnosed at Stage 4, after it has spread, survival falls from 55 per cent at one year to 26 per cent at five years. The difference is linked closely to how deep the melanoma has grown before removal.
Early melanomas are thin and confined to the upper layers of the skin. As a melanoma grows deeper, it can reach blood vessels and lymph channels, and the risk of spread rises. This is why a spot that has changed over a few weeks deserves an appointment soon, not at your next routine check. Nodular melanoma in particular can grow quickly, so a new lump should never wait.
Myths that delay diagnosis
Some common beliefs cause people to wait too long. One is that melanoma always hurts or itches. Most early melanomas cause no symptoms at all, so the absence of pain tells you nothing. Another is that a mole you have had since childhood cannot become dangerous, yet any mole that starts to change deserves a check.
A further myth is that people who tan easily are safe. A tan is a sign of skin damage, not protection against it. People with olive or darker skin still develop melanoma, even if their risk is lower. The safest approach for everyone is to watch for change and act on it.
Some people also believe a GP will remove every mole they point to. In practice, a GP removes a spot only when there is a medical reason. Many spots are simply recorded and reviewed. Asking about a mole never commits you to a procedure.
Who should pay closest attention
Everyone benefits from knowing the warning signs, but some people carry more risk. Fair skin that burns easily raises risk, as does a large number of moles. A personal or family history of melanoma is another strong risk factor. People who spent years working outdoors, or who had many sunburns in childhood, should also check their skin regularly.
Darker skin types are not immune. Melanoma in people with darker skin often appears on the soles of the feet or under the nails. A dark streak under a nail that is new or widening needs to be checked. So does a changing spot on the sole of the foot.
Children rarely develop melanoma, but the habits formed in childhood shape lifetime risk. Sunburn in early life adds to later risk, so sun protection for children is worth the effort. Parents who notice a changing mole on a child can raise it at a children's health appointment at Dandenong Doctors.
Protecting your skin from new damage
Knowing the warning signs is most useful when you pair it with prevention. Sunscreen of SPF 50 or higher, reapplied every two hours outdoors, lowers the UV that reaches your skin. A broad-brimmed hat protects the face and ears, which are common sites of skin cancer. In Victoria, sun protection is needed whenever the UV index reaches 3 or above.
How to check your own skin
A monthly self-check takes about ten minutes. Choose a room with good light and use a full-length mirror together with a hand mirror. Start at your scalp and work down, looking at the front of your body and then your back. Do not forget the soles of your feet and the spaces between your toes.
Ask a partner or family member to check areas you cannot see, such as your scalp and the back of your neck. Photos help a great deal. A dated photo of each mole you want to watch makes change much easier to spot. Take new photos in the same light and from the same distance each time.
Keep a simple record of anything new. Note where the spot is and when you first saw it. If a spot matches any letter of the ABCDE rule, or if it stands out from your other moles, book a GP appointment. Waiting to see what happens is rarely the right choice with a changing spot.
Using the rule with a partner or family member
Two sets of eyes find more than one. A partner can check your back and scalp each month, and you can do the same for them. Agree on a simple routine, such as the first weekend of each month, so the check becomes a habit. Share any photos you take, so both of you can compare them over time.
What happens when you see a GP
The GP examines the spot with a dermatoscope and usually checks the rest of your skin at the same visit. The article on what happens during a full skin check walks through each step of that examination. If the spot looks suspicious, the GP will usually recommend removing it for testing.
Suspected melanomas are generally removed whole, with a small margin of normal skin, so the pathologist can measure their depth. The guide to skin lesion and mole removal in Dandenong explains how the procedure works and what recovery involves. If the result confirms melanoma, the GP will arrange referral to a specialist for further treatment.
Regular checks with a GP add to your own monitoring. Information on skin cancer checks in Dandenong covers who should book and how often. A skin check can also be planned alongside other health screening that you are due for. Details of the skin cancer check service are on the clinic website.
The ABCDE rule works because it turns a vague worry into specific questions you can ask about a spot. It will never replace a doctor's examination, but it can prompt you to book one sooner. The mole that has changed since last summer is the one to show a GP now.