Detecting melanoma

Photo of a dermatologist inspecting someone’s skin

In order to detect melanoma 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 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 skin abnormalities. 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 mole 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. Keeping a record of things like the size of suspicious-looking moles or taking pictures of them can make it easier to tell later on whether they have changed.

It can be difficult to know what kind of changes could be 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.

Where can melanoma develop and what does it look like?

Melanoma sometimes develops inside an older mole, but it is often an entirely new skin growth. It can occur anywhere on your body, even in places hardly ever reached by sunlight: on your scalp, in the genital area or beneath your toenails or fingernails. Commonly affected areas include the chest and back in men, and the lower legs in women.

Photo: Melanoma may look like this

Melanoma typically looks like a flat, dark, irregularly colored spot on the skin. 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.

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 6 mm in diameter).

The following ABCDE checklist can help you tell if a mole has become cancerous:

Asymmetry: The mole has an uneven (asymmetrical) shape. It often has one or more raised areas and is flatter elsewhere.
Border: The mole has an irregular border (edge), and may appear ragged, blurred or notched.
Color: The mole changes color. It may be several different colors, or an unusual color such as white, blue or red.
Diameter: The diameter is greater than 6 mm (wider than an average-sized pencil).
Evolving: The mole 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. 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 6 mm.

If you have a lot of moles and aren’t sure how to best keep track of them all, it might help to use the “ugly duckling” method. “Ugly ducklings” are moles that stand 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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Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften (AWMF), Deutsche Krebsgesellschaft (DKG), Deutsche Krebshilfe (DKH). S3-Leitlinie Prävention von Hautkrebs. AWMF-Registernr.: 032-052OL. 2021.

Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften (AWMF), Deutsche Krebsgesellschaft (DKG), Deutsche Krebshilfe (DKH). S3-Leitlinie zur Diagnostik, Therapie und Nachsorge des Melanoms. AWMF-Registernr.: 032-024OL. 2020.

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National Institute for Health and Clinical Excellence (NICE). Melanoma: assessment and management (NICE Guidelines; No. 14). 2015.

Rivers JK. Is there more than one road to melanoma? Lancet 2004; 363(9410): 728-730.

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Walter FM, Birt L, Cavers D et al. 'This isn't what mine looked like': a qualitative study of symptom appraisal and help seeking in people recently diagnosed with melanoma. BMJ Open 2014; 4(7): e005566.

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. 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 July 5, 2022

Next planned update: 2025


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

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