What is a key characteristic of abnormal moles when utilizing the ABCDE rule?

In the ABCDE rule for assessing moles, a key characteristic of abnormal moles is irregular border. This aspect indicates that the edges of the mole are not smooth or are uneven, often appearing scalloped or notched. Irregular borders can be a warning sign of potential melanoma or other skin cancers, distinguishing problematic moles from benign ones, which generally have well-defined, even borders.

The other characteristics mentioned in the choices contribute to the overall assessment of moles but do not align with the definition of abnormality in the same manner. For example, color uniformity signifies that a mole has a consistent color, which is typically a sign of a benign mole. Similarly, a diameter less than 5 mm is characteristic of most non-cancerous moles, as larger diameters—typically over 6 mm—are more concerning. Lastly, symmetry refers to how evenly a mole is shaped; symmetrical moles are usually signs of normality, while asymmetrical moles raise concerns. Overall, the feature of an irregular border in a mole is a prominent indicator of potential abnormalities when utilizing the ABCDE rule.