Most people have moles, freckles, and other marks on their skin. Many remain unchanged for years, but it is helpful to become familiar with how your skin normally looks so that you can notice something new, unusual, or changing.
The ABCDE guide is a simple way to remember several visible characteristics associated with melanoma. It does not provide a diagnosis, and not every melanoma follows the ABCDE pattern, but it can help you recognize changes that should be discussed with a healthcare professional.
A — Asymmetry
Asymmetry means that one half of a mole or mark does not match the other. A common mole is often relatively balanced in shape, while a concerning mark may have two noticeably different halves.
When reviewing a mark, imagine drawing a line through its centre. Consider whether the two sides are similar in shape, colour, and overall appearance.
B — Border
Look at the outer edge of the mark. Common moles often have smoother, more clearly defined borders. A border that appears irregular, blurred, jagged, scalloped, or poorly defined may deserve closer attention.
A clear photograph can help you review the border and determine whether its shape appears to be changing.
C — Colour
A common mole is often a consistent colour throughout. A mark containing several colours or uneven areas of pigmentation may be more concerning. These variations can include different shades of brown or black and, in some cases, areas of red, white, pink, or blue.
Colour can be particularly difficult to compare between photos because it may appear different under warm indoor lighting, bright sunlight, shadows, or camera filters.
D — Diameter
Diameter refers to the width of the mark. Melanomas are often larger than approximately 6 millimetres when identified, but they can also be smaller. Size should therefore be considered alongside the other ABCDE characteristics rather than used as a firm cutoff.
Including a measurement reference in a photograph can make it easier to compare the apparent size of a mark over time.
E — Evolution
Evolution means change. A mark may be evolving if its size, shape, colour, height, texture, or overall appearance changes over time. New symptoms—such as itching, discomfort, bleeding, crusting, or swelling—should also be brought to the attention of a healthcare professional.
Evolution can be one of the most difficult characteristics to assess from memory alone. Gradual changes may be hard to recall weeks or months later, which is why a dated timeline of photographs can be useful.
Why Consistent Photos Matter
Photos can help create a visual record, but meaningful comparison requires consistency. Changes in lighting, camera distance, viewing angle, focus, and image scale can make the same mark look different from one photo to the next.
Try to photograph the same area from a similar position and under similar lighting conditions. Avoid beauty filters, strong shadows, and digital zoom. Record the date and location of the mark so that future images can be organized correctly.
Dermamark is a skin photo tracking sticker designed to provide a consistent reference in every image. Simply place it around a mark, take a smartphone photo, and build a clearer visual timeline to review over time or share with a healthcare professional.
When to Seek Professional Advice
The ABCDE guide and personal photographs can support skin awareness, but they cannot determine whether a mark is harmless or concerning. Contact a qualified healthcare professional when you notice a new or changing mark, a spot that looks different from your others, or symptoms such as persistent itching, bleeding, crusting, or soreness.
For more information, visit the American Academy of Dermatology’s guide to the ABCDEs of melanoma, the American Cancer Society’s melanoma signs and symptoms page, or the Canadian Cancer Society’s melanoma information centre.
Dermamark is intended to support personal photo tracking and record keeping. It does not diagnose, screen for, prevent, or rule out skin cancer and is not a substitute for examination by a qualified healthcare professional.