Signs and Symptoms of Melanoma Skin Cancer

Unusual moles, sores, lumps, blemishes, markings, or changes in the way an area of the skin looks or feels may be a sign of melanoma or another type of skin cancer, or a warning that it might occur.

Possible signs and symptoms of melanoma

• The most important warning sign of melanoma is a new spot on the skin or a spot that is changing in size, shape, or color.
• Another important sign is a spot that looks different from all of the other spots on your skin. (This is sometimes known as "the ugly duckling sign.")

If you have one of these warning signs, have your skin checked by a doctor.

What should a normal mole look like?

Most people have moles, and almost all moles are harmless. A normal mole is:

• Usually an evenly colored brown, tan, or black spot on the skin
• Either flat or raised
• Round or oval
• Generally smaller than 6 millimeters (about ¼ inch) across (about the width of a pencil eraser)

Some moles can be present at birth, but most appear during childhood or young adulthood. New moles that appear later in life should be checked by a doctor.

Once a mole has developed, it will usually stay the same size, shape, and color for many years. Some moles may eventually fade away.

It’s important to recognize changes in a mole's size, shape, color, or texture. These changes could suggest a melanoma is developing.

The ABCDE rule for signs of melanoma

The ABCDE rule is another guide to the usual signs of melanoma. Be on the lookout and tell your doctor about spots that have any of the following features:

• A is for Asymmetry: One half of a mole or birthmark does not match the other.
• B is for Border: The edges are irregular, ragged, notched, or blurred.
• C is for Color: The color is not the same all over and may include different shades of brown or black, or sometimes with patches of pink, red, white, or blue.
• D is for Diameter: The spot is larger than 6 millimeters across (about ¼ inch – the size of a pencil eraser), although melanomas can sometimes be smaller than this.
• E is for Evolving: The mole is changing in size, shape, or color.

Some melanomas don’t fit these rules. It’s important to tell your doctor about any changes or new spots on your skin, or growths that look different from the rest of your moles.

Other signs of melanoma on the skin

Other warning signs are:

• A sore that doesn’t heal
• Spread of pigment from the border of a spot into surrounding skin
• Redness or a new swelling beyond the border of the mole
• Change in sensation, such as itchiness, tenderness, or pain
• Change in the surface of a mole – scaliness, oozing, bleeding, or the appearance of a lump or bump

Be sure to show your doctor any areas that concern you. It’s sometimes hard to tell the difference between melanoma and an ordinary mole, even for doctors, so it’s important to show your doctor any mole that you are unsure of.

Signs of hidden melanoma

While most melanomas start on sun-exposed skin, a small portion of melanomas start in places that aren't exposed to the sun. These might look different from melanomas on the skin. For example:

• Under a fingernail or toenail (acral melanoma): May appear as a dark line or streak in the nail.
• On the palms or soles (acral melanoma): May appear as a dark, irregular areas.
• In the eye (uveal melanoma): May appear as a dark spot in the colored part of the eye (iris).
• In the mouth, nose, and genitals (mucosal melanoma): May develop as dark spots or irregular areas in these tissues.

It’s important to show a doctor anything that concerns you in these areas as well.