Melanomas can develop anywhere on your body, but most often develop in areas that have had exposure to the sun, such as your back, legs, arms and face. Melanoma can occur in areas that don't receive much sun exposure, such as the soles of your feet, palms of your hands and on fingernail beds.
The first melanoma symptoms often are:

• A change in an existing mole, or
• The development of a new, unusual-looking growth on your skin

But melanoma can also occur on otherwise normal-appearing skin.

Normal moles

Normal moles are generally a uniform color, such as tan, brown or black, with a distinct border separating the mole from your surrounding skin. They're oval or round in shape and about 1/4 inch, or 6 millimeters (mm), in diameter — the size of a pencil eraser.
Most people have between 10 and 40 moles. Many of these develop by age 20, although moles may change in appearance over time — some may even disappear with age. Some people may have one or more large (more than 1/2 inch, or 12 mm, in diameter), flat moles with irregular borders and a mixture of colors, including tan, brown, and either red or pink. Known medically as dysplastic nevi, these moles are much more likely to become cancerous (malignant) than normal moles are.

Unusual moles that may indicate melanoma

Characteristics of unusual moles that may indicate melanomas or other skin cancers follow the A-B-C-D-E guide developed by the American Academy of Dermatology:

• A is for asymmetrical shape. Look for moles with irregular shapes, such as two very different-looking halves.
• B is for irregular border. Look for moles with irregular, notched or scalloped borders — the characteristics of melanomas.
• C is for changes in color. Look for growths that have many colors or an uneven distribution of color.
• D is for diameter. Look for new growth in a mole larger than about 1/4 inch (6 millimeters).
• E is for evolving. Look for changes over time, such as a mole that grows in size or that changes color or shape. Moles may also evolve to develop new signs and symptoms, such as new itchiness or bleeding.

Other suspicious changes in a mole may include:

• Scaliness
• Itching
• Change in texture — for instance, becoming hard or lumpy
• Spreading of pigment from the mole into the surrounding skin
• Oozing or bleeding

Malignant moles vary greatly in appearance. Some may show all of the changes listed above, while others may have only one or two unusual characteristics.

Hidden melanomas
Melanomas can also develop in areas of your body that have little or no exposure to the sun, such as the spaces between your toes and on your palms, soles, scalp or genitals. These are sometimes referred to as hidden melanomas because they occur in places most people wouldn't think to check. When melanoma occurs in people with dark skin tones, it's more likely to occur in a hidden area.