10 Symptoms of Melanoma

4. Diameter

Healthy moles are generally small and flat. They do not cause pain, itching, or any other sensation. In general, moles larger than about a quarter-inch — the size of a pencil eraser — could indicate a melanoma if other characteristics, like the edges and color shade, are also problematic. A large birthmark does not mean melanoma, but if it begins to develop an irregular border or different color, or lose its symmetry, a doctor should investigate. However, smaller moles can be problematic as well, which is why watching for various signs and alarming changes is important.