First, for a successful self-exam, you obviously need to know what you're looking for. As a general rule, to spot either melanomas or non-melanoma skin cancers (such as basal cell carcinoma and squamous cell carcinoma), take note of any new moles or growths, and any existing growths that begin to grow or change significantly in any other way. Lesions that change, itch, bleed, or don't heal are also alarm signals.
It is so vital to catch melanoma, the deadliest form of skin cancer, early that physicians have developed two specific strategies for early recognition of the disease: the ABCDEs and the Ugly Duckling sign.
B - Border
The borders of an early melanoma tend to be uneven. The edges may be scalloped or notched.
Having a variety of colors is another warning signal. A number of different shades of brown, tan or black could appear. A melanoma may also become red, blue or some other color.
D - Diameter
Melanomas usually are larger in diameter than the size of the eraser on your pencil (1/4 inch or 6 mm), but they may sometimes be smaller when first detected.