The ABCDE rule is a useful way to notice potentially concerning moles, but it does not identify every melanoma. Some melanomas are small, relatively symmetrical, one colour, pink, red or skin-coloured. Others may simply look different from your other moles or change over time.
The most important message is straightforward: if a lesion is new, changing or clearly different from the rest, it is worth having it assessed. A lesion does not need to tick every ABCDE box before it deserves attention.¹˒²
What are the early signs of melanoma?
Early melanoma may appear as a new spot, a changing mole or a lesion that looks unlike the rest of your skin markings. The change may involve size, shape, colour, surface, height or sensation. It may also be a spot that repeatedly bleeds, crusts, itches or does not behave like your other moles.¹˒²
No single visual sign can diagnose melanoma. Many harmless lesions can be irregular, raised, itchy or pigmented. However, noticing a difference early and arranging professional assessment is important because melanoma is more treatable when found at an earlier stage.²
The ABCDE rule: useful, but not complete
The traditional ABCDE rule is a memory aid for recognising features that may need assessment:
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A — Asymmetry: one half does not match the other.
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B — Border: edges are uneven, scalloped, notched or poorly defined.
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C — Colour: there are different shades or uneven areas of colour.
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D — Diameter: the lesion is larger than about 6 mm, or it is smaller but growing.
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E — Evolution: the spot is changing over time.¹
ABCDE is not a diagnostic test and should not be treated as a complete checklist. Some melanomas are smaller than 6 mm. Some have fairly regular borders. Some are predominantly pink, red or skin-coloured rather than brown or black. Some early melanomas do not show obvious asymmetry or multiple colours.¹˒³
Of the ABCDE features, evolution is often particularly important. A lesion that is new or visibly changing can be more informative than a single photograph or one visual feature at a single point in time.²˒⁴
What is the ugly duckling sign?
The ugly duckling sign means a spot looks noticeably different from a person’s other moles.
Most people’s moles follow a general pattern. They may be mostly flat, mostly raised, mostly brown, mostly round or share a similar overall appearance. A lesion that clearly stands apart from that pattern—the one that looks like it does not belong—may deserve closer assessment, even if it does not obviously meet the classic ABCDE criteria.⁵
For example, if you have many small, similar brown moles and one new pink, dark, raised or irregular spot appears, that lesion may be an ugly duckling. The sign is not proof of melanoma, but it is a helpful reason to seek assessment.
Why change over time matters
Change is one of the most useful warning signs because melanomas can evolve in ways that are difficult to judge from a single glance. A lesion may become larger, darker, lighter, more raised, more uneven, more symptomatic or simply different from how it looked previously.¹˒²
Changes worth noting include:
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an increase in size;
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a new or changing shape;
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new colour variation;
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becoming darker, lighter, redder or pinker;
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becoming raised or developing a thicker area;
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new itching, tenderness, bleeding or crusting;
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a new lesion appearing in adulthood;
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a lesion that changes on photographs or mole-mapping images.
Melanoma can develop within an existing mole, but it can also arise as a completely new lesion. In fact, many melanomas develop de novo, meaning they begin as a new spot rather than from a pre-existing mole.⁶
This is why it is important to notice new lesions as well as changes in moles you have had for years.
Can melanoma be small?
Yes. Melanoma can be smaller than 6 mm in diameter. The “D” in ABCDE is intended as a prompt, not a safety threshold. A small lesion that is changing, unlike your other moles, pink, firm, newly raised or otherwise concerning, can still need medical assessment.¹˒⁶
In a study of 312 melanomas, 27.6% were 5 mm or smaller when assessed with dermoscopy, and 44.2% of these small melanomas were invasive. Small melanomas were often identified because they were new or changing.⁶
Do not wait for a spot to become large before seeking advice. Size is only one clue; change and difference often matter more.
Can melanoma be pink or skin-coloured?
Yes. Not every melanoma is brown or black. Some melanomas contain little visible pigment and may appear pink, red, pale, skin-coloured or as a shiny patch. These are often described as amelanotic or hypomelanotic melanomas.³˒⁷
Because they do not look like the classic dark mole, pink or skin-coloured melanomas can be harder to recognise. They may be mistaken for a pimple, insect bite, eczema patch, scar, sore or harmless raised bump.³˒⁷
A pink, red or skin-coloured lesion should be assessed if it is new, enlarging, persistently raised, bleeding, crusting, sore, itchy or otherwise changing. This does not mean every pink spot is melanoma. It means colour alone should not provide reassurance.
Symptoms that may matter
Melanoma is often painless, especially early on. However, symptoms can sometimes be a useful prompt to seek assessment.
Pay attention to a lesion that:
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bleeds without obvious injury;
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repeatedly crusts, breaks down or ulcerates;
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persistently itches;
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becomes tender or painful;
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repeatedly becomes inflamed;
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feels different from your other moles; or
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does not heal as expected.¹˒²
These symptoms can occur in harmless lesions and other skin conditions. They do not diagnose melanoma by themselves. But when they occur in a new, changing or unusual spot, they are worth discussing with a qualified medical practitioner.
What about nodular melanoma and the EFG rule?
Nodular melanoma can behave differently from the flatter, irregular pigmented lesions people commonly associate with melanoma. It may not follow the traditional ABCDE pattern.¹˒⁸
A helpful additional memory aid is EFG:
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E — Elevated: raised above the surrounding skin.
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F — Firm: feels firm to touch.
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G — Growing: enlarges progressively over weeks or months.¹˒⁸
Nodular melanomas may be rounder, more symmetrical and more evenly coloured than other melanomas. They can be brown, black, pink, red or skin-coloured. They may eventually bleed, crust or ulcerate.⁸
EFG is not a self-diagnostic test. It is another reminder not to dismiss a new, firm and persistently growing lump simply because it does not have an irregular border or several colours.
Where can melanoma appear?
Melanoma can occur on skin that receives a lot of sun exposure, but it can also appear in less obvious locations. This includes the scalp, back, lower legs, soles of the feet, palms of the hands, between the toes and beneath or around the nails.²˒³
Melanoma on the palms or soles is sometimes described as acral melanoma. “Acral” simply means the outer parts of the body, particularly the palms and soles. These locations should not be ignored simply because they are not routinely sun-exposed.
Under or around a nail, a concerning change might include a new or widening dark band, pigment spreading onto surrounding skin, nail distortion or a persistent change that does not fit a simple injury.³
You do not need to examine every area with anxiety. The practical approach is to remain generally familiar with your skin, ask a partner or family member to help with hard-to-see areas such as the scalp and back where appropriate, and seek assessment for a concerning new or changing spot.
Can melanoma look like a normal mole?
Sometimes. Some melanomas can look deceptively ordinary, especially early. They may be small, fairly symmetrical, one colour or similar to a harmless mole at first glance.⁶
This is why the lesion’s story matters. A mole that has always been stable may be less concerning than a new lesion in adulthood that continues to change. A spot that looks different from your own usual pattern may also warrant attention, even if it would not look alarming in isolation.²˒⁵
Professional assessment adds information that the naked eye cannot always provide.
How dermoscopy helps assess suspicious moles
Dermoscopy is a close-up skin examination using magnification and specialised light. It allows clinicians to see structures, colours and patterns within a lesion that are not visible to the naked eye.⁹
Dermoscopy can improve diagnostic assessment when used by trained clinicians, but it does not replace biopsy when tissue diagnosis is required.⁹˒¹⁰
If a lesion is suspicious, clinicians may recommend biopsy rather than observation or additional imaging. Patients should not delay assessment in the hope that imaging will avoid the need for a biopsy. The right next step depends on how the lesion appears, how it has changed and the overall clinical context.
How mole mapping can help identify change
Total body photography and digital mole mapping create a baseline record of the skin. At later appointments, photographs can be compared with earlier images to identify new lesions or visible changes in existing moles.²˒¹¹
This can be especially useful for people with many moles, atypical moles or a previous melanoma, where remembering every lesion by eye is difficult. Total body photography may be combined with sequential digital dermoscopy, which enables side-by-side comparison of selected lesions over time.²˒¹¹
Mole mapping does not independently diagnose melanoma and does not replace a clinical examination. It is a tool that can make change easier to detect and document.
When may optical biopsy be useful?
When a lesion remains diagnostically uncertain after clinical examination and dermoscopy, reflectance confocal microscopy—also called RCM or optical biopsy—may provide additional non-invasive information in selected cases.¹²
RCM uses a low-power laser to create highly magnified images of structures within living skin, at approximately cellular-level resolution. No tissue is removed. It may help clinicians obtain more information about some lesions that are difficult to classify through examination and dermoscopy alone.¹²
Not every lesion is suitable for RCM, and RCM is not used routinely for every mole. A highly suspicious melanoma should not be delayed for RCM. If tissue diagnosis is clinically required, surgical biopsy remains necessary.¹⁰˒¹²
How Skintel fits into early melanoma assessment
Skintel is a diagnostic skin imaging service. Its workflow includes full-body scanning or body mapping, high-magnification assessment of selected lesions, optical biopsy using reflectance confocal microscopy where clinically appropriate, and review by accredited skin cancer doctors. A report with follow-up recommendations is then provided.¹³
The imaging process involves melanographers, who guide patients through the imaging assessment, and accredited skin cancer doctors, who review the images and findings.¹³˒¹⁴
For selected patients, total body photography, digital dermoscopy and image comparison can help document the skin and assess lesions requiring closer attention. Where a lesion remains uncertain after examination and dermoscopy, RCM may provide additional non-invasive diagnostic information.
Skintel does not treat skin cancers. If a lesion requires biopsy, excision or other treatment, this is managed by the patient’s treating or referring clinician.
When should you get a mole checked?
Arrange medical assessment if you notice:
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a new lesion that continues to change;
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a mole changing in size, shape, colour or height;
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an ugly duckling lesion that looks different from your other moles;
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unexplained bleeding, crusting or ulceration;
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a pink, red or skin-coloured lesion that is changing;
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a small lesion that is evolving;
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a new firm and growing lump; or
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any lesion that concerns you, even if it does not fit the ABCDE rule.¹˒²
You do not need to decide whether a lesion is melanoma before booking an appointment. The purpose of professional assessment is to investigate a concern properly.
Concerned about a new or changing mole?
If you have noticed a new, changing or unusual lesion, a comprehensive skin imaging assessment may help document the skin and support clinician-led evaluation of lesions needing closer attention.
To arrange an assessment, Book a skin check at Skintel.
Medical safety disclaimer
This article provides general information only and cannot diagnose melanoma. The ABCDE rule, ugly duckling sign and other warning signs are prompts to seek assessment, not diagnostic tests. If you notice a new, changing, bleeding, painful or otherwise concerning lesion, arrange prompt assessment with a qualified medical practitioner. Do not delay because a lesion does not fit the classic ABCDE criteria.
Frequently Asked Questions
What are the first signs of melanoma?
The first sign of melanoma is often a new spot or a change in an existing mole.¹ Look for a lesion that grows, changes shape or colour, becomes raised, bleeds, crusts, itches, hurts or looks noticeably different from your other moles. These changes do not prove melanoma, but they are good reasons to arrange professional assessment rather than waiting to see whether the lesion settles.
Can melanoma be small?
Yes. Melanoma can be smaller than 6 mm.¹˒⁶ Diameter is only one part of assessment, and a small lesion that is new, changing, firm, raised, pink or unlike your other moles can still be important. Do not wait for a spot to become large before having it assessed. Change over time is often more useful than size alone.
Can melanoma be pink or skin-coloured?
Yes. Some melanomas have little visible pigment and may appear pink, red, pale or skin-coloured.³˒⁷ These lesions can be harder to recognise because they do not look like the classic dark mole. A pink or skin-coloured spot that is new, changing, persistently raised, bleeding, crusting or sore should be assessed by a qualified medical practitioner.
Can melanoma look like a normal mole?
Yes. Some early melanomas can be small, relatively symmetrical or one colour, and may not look alarming in isolation.⁶ This is why change and the ugly duckling sign are important. A lesion that is new in adulthood, evolves over time or looks unlike your other moles may need assessment even if it does not seem to meet the ABCDE criteria.
What is the ugly duckling sign?
The ugly duckling sign means that a lesion looks noticeably different from your other moles.⁵ Most people have a personal mole pattern, and a spot that clearly stands out may deserve closer assessment. It does not prove melanoma, but it is a useful warning sign—particularly when the lesion is new or changing.
Is a changing mole always melanoma?
No. Many moles and other skin lesions can change for benign reasons. But a changing mole should not be dismissed, because evolution is one of the most useful clues in early melanoma assessment.¹˒² Arrange a professional review if a lesion is changing in size, shape, colour, height, surface or symptoms, particularly if it looks different from your other moles.
Can melanoma appear suddenly?
Melanoma can appear as a completely new lesion rather than developing from a mole you have had for years.⁶ A new spot in adulthood that continues to change is worth having assessed. It may not have appeared “overnight” biologically, but it can become noticeable over a relatively short period. Do not only monitor existing moles; stay aware of new persistent spots as well.
Can melanoma occur under a nail?
Yes. Melanoma can occur beneath or around a nail. A new or widening dark band, pigment extending to surrounding skin, nail distortion or a persistent change that does not fit a simple injury should be assessed.³ Nail changes are not automatically melanoma, but they should not be ignored when they are new, changing or unexplained.
Does melanoma always follow the ABCDE rule?
No. Some melanomas, including nodular and desmoplastic melanomas, may not follow ABCD features.¹ They may be pink, skin-coloured, firm, raised and growing. The EFG reminder—elevated, firm and growing—can help prompt assessment of these lesions, but no checklist can diagnose melanoma. If a lesion is new, changing or different from the rest, have it assessed.
When should I get a mole checked?
Get a mole checked promptly if it is new, changing, bleeding, painful, persistently itchy, crusting, ulcerated or noticeably unlike your other moles.¹˒² You should also seek assessment for a small evolving lesion or a new pink, red or skin-coloured spot. It is appropriate to book an assessment whenever you are concerned, even if the lesion does not fit a checklist.
Conclusion
The ABCDE rule remains useful, but melanoma does not always look like an irregular dark mole larger than 6 mm. Some melanomas are small, pink or skin-coloured, relatively symmetrical or different only because they are changing over time.
Knowing your usual mole pattern, noticing ugly ducklings and taking new or evolving lesions seriously can help you seek assessment sooner. If a lesion is new, changing or looks different from the rest, it is worth having checked.
References
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Cancer Council Australia. Signs and symptoms of melanoma. Sydney: Cancer Council Australia; 2025.
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Mar VJ, Soyer HP, Button-Sloan A, Fishburn P, Gyorki DE, Hardy M, et al. Diagnosis and management of cutaneous melanoma. Aust J Gen Pract. 2020;49(11):733-739.
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Menzies SW, Kreusch J, Byth K, Pizzichetta MA, Marghoob A, Braun R, et al. Dermoscopic evaluation of amelanotic and hypomelanotic melanoma. Arch Dermatol. 2008;144(9):1120-1127.
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Kittler H, Pehamberger H, Wolff K, Binder M. Diagnostic accuracy of dermoscopy. Lancet Oncol. 2002;3(3):159-165.
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Grob JJ, Bonerandi JJ. The “ugly duckling” sign: identification of the common characteristics of nevi in an individual as a basis for melanoma screening. Arch Dermatol. 1998;134(1):103-104.
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Carrera C, Marchetti MA, Dusza SW, et al. Dermoscopic features and screening strategies for the detection of small-diameter melanomas. Clin Exp Dermatol. 2022;47(12):2147-2155.
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Menzies SW, Kreusch J, Byth K, Pizzichetta MA, Marghoob A, Braun R, et al. Dermoscopic evaluation of amelanotic and hypomelanotic melanoma. Arch Dermatol. 2008;144(9):1120-1127.
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Kelly JW. Nodular melanoma: how current approaches to early detection are failing. J Drugs Dermatol. 2005;4(6):790-793.
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Kittler H, Pehamberger H, Wolff K, Binder M. Diagnostic accuracy of dermoscopy. Lancet Oncol. 2002;3(3):159-165.
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Dinnes J, Deeks JJ, Chuchu N, et al. Visual inspection and dermoscopy, alone or in combination, for diagnosing keratinocyte skin cancers in adults. Cochrane Database Syst Rev. 2018;12(12):CD011901.
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Ji-Xu A, Dinnes J, Matin RN. Total body photography for the diagnosis of cutaneous melanoma in adults: a systematic review and meta-analysis. Br J Dermatol. 2021;185(2):302-312.
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Dinnes J, Bamber J, Chuchu N, et al. Reflectance confocal microscopy for diagnosing cutaneous melanoma in adults. Cochrane Database Syst Rev. 2018;12(12):CD013190.
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Skintel. The Skintel skin check. Melbourne: Skintel; accessed 2026 Sep 6.
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Skintel. About us. Melbourne: Skintel; accessed 2026 Sep 6.
