Mole Changes (ABCDE)

You may think that every large or dark mole is melanoma, or that a small mole cannot be cancerous. Most moles are harmless. What matters most is whether a mark is new, changing or noticeably different from your other marks. The ABCDE guide helps you notice change, but it cannot diagnose or exclude melanoma.

Most moles are harmless A mole is a collection of pigment producing cells within the skin. Normal moles may be flat or raised, brown, black, pink or skin coloured, smooth or slightly textured, present from childhood, or acquired gradually through early life. People naturally differ in the number, colour and appearance of their moles. A mole does not need to look identical to an illustration to be normal or abnormal. Melanoma is one type of skin cancer Melanoma develops from pigment producing cells called melanocytes. It may arise within an existing mole, as a new pigmented mark, as a less visibly pigmented or pink lesion, beneath a nail, on the palm or sole, or in less commonly exposed skin. Early assessment matters because melanoma is generally easier to treat when identified before it has grown more deeply. ABCDE is a memory aid The ABCDE guide helps you notice features associated with melanoma: A for Asymmetry, B for Border, C for Colour, D for Diameter, and E for Evolving. It is not a scoring system for self diagnosis. A benign mole may have one unusual feature, while a melanoma may not display every feature. A means asymmetry A symmetrical mole has broadly similar halves. Asymmetry means that one side differs from the other in shape, height, pattern or colour distribution. Do not expect perfect geometric symmetry. The question is whether the overall mark has become uneven or structurally irregular. B means border A usual mole often has a reasonably smooth and clearly defined edge. A concerning border may become irregular, ragged, notched, blurred, or unevenly spreading. A border that changes over time deserves particular attention. C means colour Many harmless moles have a consistent colour. A concerning lesion may show several shades of brown or black, uneven colour distribution, new darkening, new loss of pigment, pink, red, white, grey or blue areas, or colour spreading beyond the previous border. Colour must be judged against your usual skin and other moles. Melanoma is not always dark. D means diameter A diameter greater than about 6 millimetres is commonly included in ABCDE guides. However, many large moles are harmless, and some melanomas are smaller than 6 millimetres. Diameter alone cannot determine risk. Change in diameter may be more informative than a single measurement. E means evolving Evolving means changing over time. A mole may change in size, shape, colour, height, texture, sensation, surface, or bleeding or crusting. Evolution is particularly important because a stable unusual looking mole may be less concerning than a previously ordinary mole that is now changing. Notice the "ugly duckling" Most of your moles often share a broad family resemblance. A mark that looks distinctly different from all the others is sometimes called an ugly duckling. It may differ in darkness, shape, size, texture, location, or recent behaviour. This is not a diagnosis. It is a reason to look more carefully and seek assessment if the difference is new or unexplained. Symptoms can matter Arrange GP assessment for a mole that becomes painful, itchy, inflamed, bleeding, crusty, ulcerated, or persistently sore. An irritated mole can bleed after catching on clothing, but repeated spontaneous bleeding or surface change should not be dismissed. A new mark may require review See a GP if you develop a new unusual skin mark persisting for several weeks, a growing lump, a sore that does not heal, a scaly or crusted area that repeatedly breaks down. A new pigmented streak beneath a nail, pigment spreading onto the skin around a nail, or a persistent changing mark on a palm or sole. Not every skin cancer looks like a conventional mole. Nail changes should not be ignored A dark line beneath a nail may result from injury, bleeding beneath the nail, normal pigmentation, medicine effects, infection, or a pigmented lesion. Seek assessment when a dark mark has no clear injury explanation, widens, changes, involves one nail, extends onto surrounding skin, or persists as the nail grows. Check your skin systematically You can check your face and ears, scalp, neck, chest and abdomen, back, arms and hands, between fingers, legs and feet, soles, between toes, nails, and buttocks and genital skin where appropriate. Use mirrors or ask someone you trust to help with areas you cannot see. The purpose is to learn your normal pattern and detect change, not to inspect yourself constantly. Photographs can document change A clear photograph may help when taken in good, consistent lighting, the same distance is used, a ruler is placed beside the lesion without covering it, the date is recorded, and image privacy is protected. Do not wait for a second photograph before seeking help when a lesion is already changing, bleeding or otherwise concerning. Filters, magnification and phone cameras can alter colour. A photograph cannot replace examination. Apps cannot safely rule out melanoma Consumer apps may estimate whether a mark looks unusual. Their output should not be used to cancel a GP appointment, delay referral, diagnose melanoma, reassure you that a changing lesion is harmless, or decide to remove a lesion yourself. Do not cut, burn or freeze a mole yourself Home removal can cause bleeding, cause infection, leave a scar, partially remove the lesion, delay diagnosis, or destroy tissue needed for laboratory examination. A suspicious lesion should be assessed and, where appropriate, removed in a way that allows histological examination. A clinician uses more than ABCDE Your clinician may assess recent change, appearance compared with your other moles, personal and family skin previous cancer, sun and ultraviolet exposure, immune suppression, the lesion's surface, nail or mucosal involvement, and dermoscopic features. Dermoscopy uses a magnifying device and specialised illumination to examine structures not clearly visible to the naked eye. A weighted seven point checklist supports referral For suspicious pigmented lesions, clinicians may use a weighted seven point checklist. Major features score two points each: change in size, irregular shape, irregular colour. Minor features score one point each: diameter of 7 millimetres or more, inflammation, oozing, change in sensation. A score of three or more supports referral on a suspected cancer pathway. Dermoscopic suspicion or features of nodular melanoma may also prompt referral. This is a clinical tool, not a home diagnostic test. An urgent referral does not mean cancer is confirmed An urgent suspected cancer referral means that specialist assessment should not be delayed. The specialist may use dermoscopy, clinical photography, examination of the rest of the skin, excision biopsy, and histology. Many urgently referred lesions are benign. A diagnosis of melanoma requires examination of tissue by a pathology laboratory. Mole colour should be judged across skin tones Melanoma can occur in people of every skin colour. Changes may be harder to notice when public examples do not resemble your skin. Pay attention to new differences from your baseline, palms and soles, nails, less exposed areas, pink or non pigmented lesions, and texture and surface changes. A changing lesion should be assessed regardless of whether you consider your skin at high or low risk. Sun protection reduces future skin damage You can reduce ultraviolet exposure by seeking shade during strong sunlight, wearing protective clothing, wearing a suitable hat, using broad spectrum sunscreen, reapplying sunscreen as directed, avoiding deliberate sunburn, and avoiding sunbeds. Sun protection reduces risk but does not remove the need to assess a changing lesion.

A mole should be understood through comparison and change over time. A safe skin check asks whether the mark is new, whether its size, shape, colour or surface has changed, whether it stands out from your other moles, whether it is itching, painful, bleeding or crusting, and whether there is an unexplained dark mark under a nail. ABCDE is an awareness guide clinical referral decisions use professional assessment rather than one feature alone.