The early stages of melanoma appear as changes in color, size and shape of a mole, the American Cancer Society says. Often melanoma looks different from all other moles or marks on the skin. It is important to examine the skin closely every month to detect melanoma early.
The ABCDE rule is a guide to help people remember what to look for when conducting a monthly skin self-exam, the American Cancer Society explains. "A" stands for asymmetry. Any birthmark or mole that doesn't have matching sides if you divide it in half is asymmetric, which can be a warning sign. "B" is for borders, which are irregular, blurred or notched. "C" stands for color. In melanoma, moles are more than one color, including different shades of brown, black, blue and red. "D" stands for diameter, and moles larger than a pencil eraser could spell trouble. Finally, "E" stands for evolving: a mole or birthmark that is changing color, size or shape.
Other signs of melanoma include a sore that does not heal or a mole that has changes in height or how it feels, the American Cancer Society states. A mole that suddenly begins itching or hurting may be melanoma. Early treatment greatly reduces the survival rate of melanoma, and monthly self-exams are essential for early detection.