Signs and Symptoms of Melanoma Skin Cancer

Unusual moles, sores, lumps, markings, or changes in how your skin looks or feels might be a sign of melanoma or another type of skin cancer, or a warning that it might occur.

What does a normal mole look like?

Most people with light skin tones 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
• Usually smaller than 6 mm across, about the width of a pencil eraser

Some moles might be present at birth, but most appear during childhood or young adulthood. 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 might eventually fade away.

Atypical moles (dysplastic nevi) look a little like normal moles but have some features of melanoma. They are often larger than other moles and have an abnormal shape or color.

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

Key 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 the other spots on your skin. This is sometimes known as “the ugly duckling sign.”

The ABCDE rule for signs of melanoma

The ABCDE rule is another guide that can help you decide if you need to see a doctor to check whether a spot might be melanoma.

• A is for Asymmetry: One half of a mole 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 might include different shades of brown, black, pink, red, white, or blue.
• D is for Diameter: The spot is larger than 6 mm (the size of a pencil eraser) across, although melanomas can sometimes be smaller than this.
• E is for Evolving: The mole is changing in size, shape, or color.

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 on your skin that concern you. It’s sometimes hard to tell the difference between melanoma and an ordinary mole, so it’s important to show your doctor any mole that you are unsure of.

Signs of melanoma in harder-to-find areas

Although 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.

• Under a fingernail or toenail (acral melanoma): Might appear as a dark line or streak in the nail.
• On the palms or soles (acral melanoma): Might appear as a dark, irregular area.
• In the mouth, nose, or genitals (mucosal melanoma): Might develop as a dark spot or irregular area.
• In the eye (ocular melanoma): Might appear as a dark spot in the colored part of the eye (iris).

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