What are the signs and symptoms of melanoma?

Melanoma is a cancer that usually starts in the skin. A change in the shape, colour or size of a mole is usually the first sign of melanoma. A melanoma can start either:

  • as a new mole
  • in a mole you already have.

Most melanomas start with a new, abnormal-looking mole on your skin. This usually looks like a dark area, although melanomas can have more than one colour. Other melanomas develop from a mole you already have that changes over weeks or months.

It can be difficult to tell the difference between a melanoma and a normal mole. With moles or other skin changes, it is a good idea to learn to recognise any new or changing areas on your skin. This helps you to recognise what is sometimes called the ‘ugly duckling’ sign. This is a mole that stands out because it looks different to other moles. Always ask your GP to check anything that looks different or unusual.

The ABCDE check list explains what to look for when checking moles or other skin changes.

A – Asymmetry

Most melanomas are likely to be uneven or irregular in shape (asymmetrical). Ordinary moles are usually more even and both halves look mostly the same (symmetrical).

Melanoma with assymetric shape

A melanoma, which has an asymmetrical shape.
Image: Melanoma with asymmetrical shape

B – Border

The edges around a melanoma (border) are more likely to be uneven, irregular or jagged. Ordinary moles usually have a clear, smooth-edged border.

Melanoma with irregular border

A melanoma with an irregular shaped border and edge
Image: Melanoma with irregular border

C – Colour

Melanomas are usually more than one colour. They may have different shades, such as brown mixed with a black, red, pink, white or blue tint. Normal moles usually only have shades of brown.

If you have red or fair hair and pale skin, the melanoma may only be red or pink with no brown. This is called amelanotic melanoma. It is much less common.

Melanoma with colour difference

A melanoma with different colours and some black areas
Image: Melanoma with a colour difference

D – Diameter (width)

Melanomas are usually more than 6mm wide. Normal moles are usually about the size of the blunt end of a pencil, or smaller.

If you have lots of large moles, some of them may be larger than 5mm in diameter. These are likely to have been there for years without changing. But it is recommended that people with lots of moles or bigger moles get them checked by a dermatologist. This is important if you have had changes to moles in the past.

E – Evolving (changing)

Look for changes in the size, shape or colour of a mole. The change in shape can include the area becoming raised or dome-shaped. Or, if the mole is flat, it may stay that way but become wider.

If you have black or brown skin

If you have black or brown skin, it can be harder to see the signs of melanoma. Black and Asian people have a lower risk of melanoma. But this does not mean you have no risk. It is still important to be aware of skin changes that may be linked to a skin cancer.

Acral lentiginous melanoma is an uncommon type of melanoma. But it is more common in Black and Asian people. It usually develops in areas of skin that get little sun exposure, such as:

  • the palms of the hands
  • soles of the feet
  • nail areas, for example under the fingernails or toenails.

Look for anything new, changing or unusual on both sun-exposed and sun-protected areas of the body.

When to see a doctor

Visit your GP straight away if you have:

  • any of the ABCDE signs or the ‘ugly duckling’ sign (see above)
  • any unusual marks on the skin that last for more than a few weeks
  • a mole that tingles or itches
  • a mole that develops a crust or bleeds
  • something growing under a nail, or a new dark-coloured stripe along part of the nail.

Checking your skin

Checking your skin is very important. Early melanoma is usually cured with treatment. If you have any possible signs or symptoms of melanoma or other skin cancer, see your GP straight away.

By regularly checking your skin, you get to know where your moles, birth marks, and other marks are. This gets easier as you become more familiar with your skin and what your moles normally look like. You will then notice any changes or new signs or symptoms.

Here are some tips:

  • use the ABCDE guide to help you
  • a good time to check could be after a shower or bath
  • make sure you have plenty of light
  • use a full-length mirror and a small handheld mirror for hard-to-see areas
  • ask a relative or friend to check your back, neck and other hard-to-see areas
  • check areas that are not exposed to the sun, such as genitals, fingernails, toenails, palms of hands and soles of feet
  • use a comb or a blow dryer to move your hair so that you can see better when checking your scalp
  • keep notes or take pictures of your moles so you can notice changes quickly.

We understand that showing any symptoms of what could be melanoma is worrying. The most important thing is to speak to your GP as soon as possible. We're also here if you need someone to talk to. You can:

About our information

  • References

    Below is a sample of the sources used in our melanoma information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk

    Michielin O, van Akkooi ACJ, Ascierto PA, et al. Cutaneous melanoma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Annals of Oncology. 2019; 30, 12, 1884-1901 [accessed May 2022].

    Michielin O, van Akkooi ACJ, Ascierto PA, et al. ESMO consensus conference recommendations on the management of locoregional melanoma: under the auspices of the ESMO Guidelines Committee. Annals of Oncology. 2020; 31, 11, 1449-1461 [accessed May 2022].

    Peach H, Board R, Cook M, et al. Current role of sentinel lymph node biopsy in the management of cutaneous melanoma: A UK consensus statement. Journal of Plastic, Reconstructive & Aesthetic Surgery. 2020; 73, 1, 36-42 [accessed May 2022].

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editor, Dr Samra Turajlic, Consultant Medical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

The language we use

We want everyone affected by cancer to feel our information is written for them.

We want our information to be as clear as possible. To do this, we try to:

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We use gender-inclusive language and talk to our readers as ‘you’ so that everyone feels included. Where clinically necessary we use the terms ‘men’ and ‘women’ or ‘male’ and ‘female’. For example, we do so when talking about parts of the body or mentioning statistics or research about who is affected.

You can read more about how we produce our information here.

Date reviewed

Reviewed: 01 October 2022
Next review: 01 October 2025
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

This means it is easy to use, up-to-date and based on the latest evidence. Learn more about how we produce our information.