Detecting melanoma

Photo of a dermatologist inspecting someone’s skin

In order to detect melanoma skin cancer early on, you can either check your skin for abnormalities yourself or have a doctor examine it. Skin cancer can be treated more effectively if it is detected early on, before it spreads to other parts of the body.

The older you get, the more your skin changes, and new moles or age spots (also known as liver spots or solar lentigines) may develop. This is a normal part of aging. So some people decide to wait and keep an eye on any unusual spots or patches of skin. Others want to know right away if something is wrong, and go to a doctor to have it checked out. But it is only rarely a serious disease like cancer.

People who have been diagnosed with melanoma say that the affected spot or patch of skin changed in size, shape or color before. Carefully checking your skin on a regular basis is a good way to notice any changes.

A full-body check involves inspecting every square inch of your skin, including the skin between your toes, on the soles of your feet, your ears, scalp, back, bottom and in your genital area. When checking parts of your body that are hard for you to see, it can be helpful to use a mirror or ask someone to help. That can be useful when checking your scalp, too – especially if you have very thick hair. Noting down the size of abnormal areas of skin or taking photos can make it easier to see whether they've changed the next time you check (either together with your doctor or using a special app).

It may be difficult to know what kind of changes are dangerous. If you think that something on your skin might be abnormal, and if it doesn't go away within 4 to 8 weeks, it's best to see a doctor. It can be harder to recognize melanoma on dark skin or very dark skin than on lighter skin.

Where can melanoma develop and what does it look like?

Melanoma sometimes develops inside an existing mole, but it is very often an entirely new skin growth.

In people with light skin, commonly affected areas include the chest and back in men, and the lower legs in women. But melanoma can occur anywhere on your body – even in places hardly ever reached by sunlight, like your scalp, genital area or beneath your toenails or fingernails.

On light skin, melanoma typically looks like a flat, dark, irregularly colored spot or patch. It may be brown or black, bluish, reddish or – in rare cases – even white or partly skin-colored. Sometimes melanomas appear as slightly raised brownish-black bumps.

Older people may develop a pre-cancerous condition called lentigo maligna. This appears as brown to dark-brown patches of skin with irregular color. The patches are most often found on skin that is frequently exposed to sunlight.

Melanoma skin cancer may look like this on light skin:

Illustration: Melanoma skin cancer on the knee (light skin)
Illustration: Melanoma skin cancer on the neck (light skin)
Illustration: Melanoma skin cancer on the chest (light skin)
Illustration: Melanoma skin cancer on the shoulder (light skin)
Illustration: Melanoma skin cancer on the cheek (light skin)

On dark skin or very dark skin, it’s often harder to recognize melanoma. Sometimes it just looks like a somewhat darker spot on dark skin, so it might not stand out as much. But it may be colorless, pink or red instead. It also typically develops on other parts of the body than it does in people with light skin. For example,

  • the soles of the feet or the skin between the toes,
  • the palms of the hands or the skin under the nails,
  • the eyes or mouth, and
  • the genitals.

What's more, people with dark skin often have harmless dark stripes or patches that are hard to tell apart from melanoma. These are especially common under the nails, on the lips and inside the mouth.

Melanoma skin cancer may look like this on dark skin:

Illustration: Melanoma skin cancer under the foot (dark skin)
Illustration: Melanoma skin cancer on a finger (dark skin)

What is the ABCDE rule about and what is the “ugly duckling” rule?

Healthy moles are usually round or oval in shape and tend to be only one color. They normally aren't very big (less than 5 millimeters in diameter).

The following ABCDE checklist can help to tell melanoma apart from a normal mole:

Asymmetry: The spot or patch has an uneven (asymmetrical) shape. It often has one or more raised areas and is flatter elsewhere.
Border: It has an irregular border (edge) that is frayed, fuzzy or jagged.
Color: The spot or patch changes color. It may be several different colors, or an unusual color such as white, blue or red.
Diameter: The diameter is greater than 5 millimeters (wider than an average-sized pencil).
Evolving: The patch or spot is changing: It might bleed, leak fluid, itch or crust over. Changes in size, shape, color or the surface are possible, and the mole may become raised.

The ABCDE rule helps to recognize melanoma, regardless of the color of your skin. But not all criteria apply to every melanoma: For instance, if it starts growing on normal skin (not in an existing mole), it often has a smaller diameter than 5 millimeters.

If you have a lot of moles and aren’t sure how to best keep track of them all, it might help to look out for an “ugly duckling” that stands out from the crowd. This can make it easier to spot abnormal changes in the skin.

In Germany, statutory health insurers cover the costs of skin cancer every two years in people aged 35 and over.

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Bendick C. Besonderheiten der nichtweißen Haut. In: Braun-Falco's Dermatologie, Venerologie und Allergologie. Berlin: Springer; 2017.

Dadzie OE, Petit A, Alexis AF. Ethnic Dermatology: Principles and Practice. Hoboken: Wiley-Blackwell; 2013.

Gloster HM, Neal K. Skin cancer in skin of color. J Am Acad Dermatol 2006; 55(5): 741-760; quiz 761-744.

Hogue L, Harvey VM. Basal Cell Carcinoma, Squamous Cell Carcinoma, and Cutaneous Melanoma in Skin of Color Patients. Dermatol Clin 2019; 37(4): 519-526.

Jackson BA. Nonmelanoma skin cancer in persons of color. Semin Cutan Med Surg 2009; 28(2): 93-95.

IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. informedhealth.org can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

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Updated on February 21, 2024

Next planned update: 2027

Publisher:

Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

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