Toolbox - the ABCDE criteria for pigmented skin lesions
Dermatology specialists Dr Veronique Bataille and Dr Samantha Anthony provide a guide to using the ABCDE criteria in primary care.
The ABCDE criteria represent a method used to evaluate pigmented (melanocytic) skin lesions in order to aid the detection of malignant melanoma.
When to use it
The presence of any of the ABCDE features should raise suspicion of a melanoma.
It can be used to assess a single mole at the time of presentation, as well as for the monitoring of longstanding or multiple moles for changes over time, which may indicate transformation to a melanoma.
It is helpful to use when considering whether to refer a patient on the urgent skin cancer two week wait pathway, with or without the use of other assessment tools. The tool can be used by both clinicians and patients and the simple acronym can quickly and easily be taught to patients for self-monitoring of their moles.
The ABCDE criteria
A: Asymmetry – is the mole oval/round or is it an odd shape? If divided in half, is the mole a mirror image of itself in both halves?
B: Border irregularity – is the outline smooth or ragged/blurred/notched?
C: Colour change or variability – is the colour of the mole even all the way through?
Does the mole contain shades of black/dark brown/grey/blue/white/red in whole or part?
D: Diameter greater than 6mm or change in diameter – is the mole larger than the others or atypical in appearance? Has the mole grown?
E: Evolution/Elevation – is the mole changing over time in size, shape or colour? Is it becoming raised?
There is no score and all points in the list are regarded as suspicious – not all of them will be malignant melanomas but these criteria can help in selecting suspicious lesions. For elevation you need evolution – change over time – so this will not mean that all raised moles will need referral if they do not change.
The ABCD criteria, first introduced in 1985 and expanded to ABCDE in 2004, was introduced to aid non-experts’ diagnosis of pigmented lesions, and over the years has been promoted widely.1,2
Although it is a very useful global tool which highlights important features found in melanoma, there are important considerations when using the criteria:
- The ABCDE criteria are not very specific. Distinguishing true melanocytic lesions from other pigmented lesions such as benign seborrhoeic keratoses can be difficult.3 Indeed, some benign naevi can display some or all of the criteria and can change in an innocent way, presenting a challenge to distinguish from a true melanoma
- Relying on the ABCDE alone may result in overlooking small or early melanomas which may lack these criteria4
- There is relatively low sensitivity of clinical diagnoses of melanoma even among dermatologists and melanomas may be missed without other strategies to enhance recognition5,6
Additional helpful adjuncts to support assessment with the ABCDE tool:
- Photographs – for clinicians, combining dermoscopy and photographs (with and without dermoscopy) will increase the chance of detecting malignant change in lesions over time. Benign moles can change but these changes occur over many years. Photography is also helpful for patients to self-monitor for changs
- Measurements of the lesion
Other useful points to consider when assessing/monitoring a pigmented lesion:
- Bleeding/ulceration/itching – although these are late signs, and melanoma should ideally be picked up earlier. Itching is not a very specific sign this may be a temporary feature in benign moles
- A check at three months is useful to identify stability or change in a longstanding mole. Patients can be advised to self-monitor monthly – remember patients with atypical mole syndrome have a 10 times increased risk of melanoma
Are there any other tools for assessing melanoma risk?
- The “ugly duckling” concept states that within the same individual a melanoma will stand out as having a pattern different from that of their other moles.7 Patients with atypical mole syndrome (more than 50 moles, with three or more being atypical) have large atypical naevi which can score highly on the ABCDE criteria, but the moles are largely stable and only need monitoring. The “ugly duckling” sign is especially useful in these patients
- The Glasgow 7-point checklist describes three major and four minor criteria for assessment of moles and consideration of urgent referral for suspected skin cancer.8 A score of 3 points or more is suspicious:
Major features (2 points each)
- change in size
- irregular shape
- irregular colour
Minor features (1 point each)
- largest diameter 7mm or more
- change in sensation
The 7-point checklist is missing asymmetry, which is a crucial sign, and the minor features are not that specific so the checklist is not used as much as the ABCDE criteria. When present, these minor features are often seen far too late in melanoma and melanomas should be picked up earlier.
- Amelanotic (non-pigmented) melanoma can be mistaken for pyogenic granuloma. Pyogenic granuloma usually grows much faster (over a few weeks) than amelanotic melanoma (a few months). Always send for histology and avoid cauterising or freezing without sending for anlaysis. Refer urgently if usual pyogenic granuloma treatments are not effective
- Nails – subungual melanoma. These have specific diagnostic criteria
- Melanoma is extremely rare in non-caucasians, but in this group they can be found on the palms, soles and subungual
- Melanoma on the palms and soles are rare but beware of red ulcerated non-healing lesions on the sole. They are often mistaken for common ulcers and viral warts and therefore diagnosis can be delayed
- Nodular melanoma can be completely symmetrical but often very darkly pigmented, or red (amelanotic). Dermoscopy is helpful to differentiate from pyogenic granuloma and haemangioma
- Sites that are difficult to self-monitor. Where possible involvement of a partner can lead to earlier detection
- Family history of melanoma, pancreatic cancer, or a strong family history of different types of cancers in first or second degree relatives can point to a strong susceptibility to developing melanoma. Atypical mole syndrome may also be a marker of risk
- Melanoma is very rare before puberty so consider other diagnoses when faced with a pigmented lesion in a child
Dr Veronique Bataille is a consultant dermatologist at West Hertfordshire NHS Hospitals Trust, honorary senior clinical research fellow at King’s College London, honorary clinical lecturer at the University of Hertfordshire and in private practice in Hertfordshire and London.
Dr Samantha Anthony is an associate specialist in dermatology at West Hertfordshire NHS Hospitals Trust and honorary clinical lecturer at the University of Hertfordshire.
- Friedman RJ, Rigel DS, Kopf AW. (1985) Early detection of malignant melanoma: the role of physician examination and self-examination of the skin. CA: a cancer journal for clinicians, 35 (3); 130-151
- Abbasi NR, Shaw HM, Rigel DS et al. (2004) Early diagnosis of cutaneous melanoma: revisiting the ABCD criteria. JAMA, 292 (22); 2771-2776
- Aldridge RB, Zanotto M, Ballerini L et al. (2011) Novice identification of melanoma: not quite as straightforward as the ABCDs. Acta dermato-venereologica, 91 (2); 125-130
- Bono A, Bartoli C, Moglia D et al. (1999) Small melanomas: a clinical study on 270 consecutive cases of cutaneous melanoma. Melanoma research, 9 (6); 583-586
- Grin CM, Kopf AW, Welkovich B et al. (1990) Accuracy in the clinical diagnosis of malignant melanoma. Archives of dermatology, 126 (6); 763-766
- Scope A, Marghoob A. (2007) The “Ugly Duckling” sign: an early melanoma recognition tool for clinicians and the public. The Melanoma Letter, 25(3); 1-3
- Grob JJ, Bonerandi JJ. (1998) The ‘ugly duckling’ sign: identification of the common characteristics of naevi in an individual as a basis for melanoma screening. Archives ofdermatology, 134 (1); 103-104
- Mackie R. (1990) Clinical recognition of early invasive malignant melanoma. BMJ, 301 (6759); 1005-1006
Marsden J, Newton-Bishop JA, Burrows L et al. (2010) Guidelines for management of cutaneous melanoma. British Journal of Dermatology, 163; 238-256