The first sign of melanoma is often a change in a mole, or the appearance of a new mole. The ABCDE rule can help you tell a normal mole from one that might be melanoma. The ABCDE rule is:

• Asymmetry. One half of the mole does not match the other half.
• Border irregularity. The edges of the mole are ragged or irregular.
• Color. The mole has different colors in it. It may be tan, brown, black, red, or other colors. Or it may have areas that seem to have lost color.
• Diameter. The mole is bigger than 6 millimeters across, about the size of a pencil eraser. But some melanomas can be smaller.
• Evolving. A mole changes in size, shape, or color.

Other signs and symptoms that may be melanoma include:

• A mole that itches or is sore.
• A mole that oozes, bleeds, or becomes crusty.
• A mole that looks different from your other moles.
• A sore that doesn't heal.
• A mole or sore that becomes red or swells at its edges or beyond.

Become familiar with the way your moles look so you will know if they're changing. Take note of any new moles that appear on your skin.

Most moles are not melanomas. But it's important to see your doctor if you have moles or other spots on your skin with the features above. Also see your doctor if you are worried about a spot on your skin for some other reason. Your doctor will examine the mole and do testing on it to find out if it is cancer.