Signs and symptoms

Melanomas can start with a change to normal skin. This may look like a dark area or an abnormal new mole. You should check your skin regularly and speak to your GP if you notice any changes.

Other melanomas develop in a mole or freckle that you already have. It can be difficult to tell the difference between a melanoma and a normal-looking mole.

The ABCDE list helps you know what to look for:

  • A – Asymmetrical moles – irregular in shape
  • B – Border of a mole – blurred or has jagged edges
  • C – Colour of a mole – if a mole has more than one colour
  • D – Diameter (width) – irregular moles are usually larger than 7mm
  • E – Evolving – melanoma moles often change (evolve).

If you notice any of these signs, or if you have any marks on your skin or a mole that tingles or bleeds, you should visit your doctor straight away.

Symptoms of melanoma

About half of all melanomas start with a change in previously normal-looking skin. This usually looks like a dark area or an abnormal new mole that changes over weeks or months. Other melanomas develop from a mole that you already have.

It can be difficult to tell the difference between a melanoma and a normal mole. The following checklist is known as the ABCDE list. It helps explain what to look for.

Photographs are from the website of the National Cancer Institute (cancer.gov).

A – Asymmetry

Most melanomas are likely to be irregular or asymmetrical. Ordinary moles are usually symmetrical (both halves look the same).

Photographs showing melanoma symptom A - asymmetry
Photographs showing melanoma symptom A - asymmetry

The left photograph shows a melanoma with an asymmetrical shape. The right photograph shows a normal mole with no asymmetry.

B – Border

Melanomas are more likely to have a blurred or irregular border with jagged edges. Ordinary moles usually have a well-defined, smooth-edged border. 

Photographs showing melanoma symptom B - border.
Photographs showing melanoma symptom B - border.

The left photograph shows a melanoma with an irregular border. The right photograph shows a normal mole with a clear border.

C – Colour

Melanomas tend to be more than one colour. They may have different shades, such as brown mixed with a black, red, pink, white or bluish tint. Normal moles tend to be one shade of brown.

Photographs showing melanoma symptom C - colour.
Photographs showing melanoma symptom C - colour.

The left photograph shows a melanoma with colour difference. The right photograph shows a normal mole with no colour difference.

D – Diameter (width)

Melanomas are usually more than 6mm wide. Normal moles are not usually bigger than the blunt end of a pencil.

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 change. But it is recommended that people with large moles get them checked by a dermatologist.

Photographs showing melanoma symptom D - diameter.
Photographs showing melanoma symptom D - diameter.

The left photograph shows a melanoma with diameter change. The right photograph shows a normal mole with no change in diameter.

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.


When to see a doctor

Visit your doctor straight away if you have:

  • any of the ABCDE signs
  • 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.

A good time to check your skin is after a bath or shower. Make sure you have plenty of light. Use a full-length mirror and a small hand held mirror for areas that are hard to see. This will get easier with time, as you become more familiar with your skin and what your moles normally look like.

You can ask your partner, a relative or friend to look at your back, neck and parts of your skin that are hard to see. You could also take pictures of your moles so you can see if there are any changes over time. Checking for these signs is very important, as melanoma can usually be cured if it is found at an early stage.

I noticed a slight change in the mole. The results showed it was a melanoma. They congratulated me on spotting it and I think myself very lucky. I think only by reading about the signs of cancer on website like Macmillan’s, I was able to spot it very early.

Jessica

Back to Understanding melanoma

Cancer and cell types

Cancers are grouped into types. Types of cancer often behave and respond to treatments in different ways.

How is it treated?

There are five main types of cancer treatment. You may receive one, or a combination of treatments, depending on your cancer type.

The skin

The skin is divided into two main layers - the outer layer (epidermis), and a layer underneath (dermis).

What is melanoma?

Melanoma is a type of skin cancer. It develops from cells in the skin called melanocytes.

Why do cancers come back?

Sometimes, tiny cancer cells are left behind after cancer treatment. These can divide to form a new tumour.