There are a number of signs you can look for to tell a benign mole from a malignant mole, which is often how the skin cancer melanoma starts. A relatively large mole may be indicative of a problem, as can one that has irregularities in color. Look for moles that are asymmetrical in shape, and that have irregular borders or where the color from the mole appears to spread into the surrounding skin. Another sign to look for is if the mole's characteristics change over time. Malignant moles may also display symptoms a normal mole will not, like itching, scaling, or bleeding.
It is fairly common for a cancerous mole to be larger than any other moles you might have. While it is possible for a benign mole to be quite large, it is probably best to have a doctor check any that you have. A good basic standard is to question any mole that is larger than 6 millimeters across.
Another common quality of malignant moles is color irregularity. This means you will see several different shades of color, often ranging from red to brown to black, within the mole. In contrast, benign moles are typically just one color throughout.
If you have a cancerous mole, it may be asymmetrical. This means that the shape of one side of the mole will be different from the shape of the other, and if you were to draw a line down the middle of it these differences would be very obvious. In addition to this, the borders of the mole might appear irregular. They may be notched or scalloped rather than smooth, and can even have areas of pigment outside of the main body of the mole. Instead of being distinct from the surrounding skin, the edges of the mole may not be clearly delineated and the pigment may appear to blur or seep into it.
A malignant mole tends to change fairly rapidly, so watch for lesions with shifting characteristics. This can mean it grows bigger or changes shape or color. If you have a mole that you see changing in appearance, or that develops symptoms like oozing or bleeding, have it examined by a doctor as soon as possible.
The final way to spot a malignant mole is to look for abnormal symptoms. Benign moles do not typically become scaly or crusty. They do not usually seep or bleed, nor do they cause pain or itching. Any of these symptoms should be a sign to get your mole examined.
