Skin cancer symptoms and what it looks like: a clear, kind guide

The short answer

The main skin cancer symptoms are a new mole, a change in an existing mole, or a spot or sore that will not heal. Most skin changes are harmless. But because skin cancer is highly treatable when caught early, anything new, changing, or lasting more than a few weeks is worth showing your GP.

In short

• Main symptoms: a new or changing mole, or a patch or sore that will not heal.
• Use the ABCDE rule for moles: Asymmetry, Border, Colour, Diameter, and Evolving or changing.
• Most skin cancer is caused by ultraviolet light, from the sun and sunbeds, so it is largely preventable.
• Two broad groups: common, very treatable non-melanoma skin cancer, and less common but more serious melanoma.
• General information, not medical advice. Show your GP anything new, changing, or that will not heal.

Around 86% of melanoma skin cancers in the UK are caused by too much ultraviolet light, which means most are preventable. Source: Cancer Research UK.

Counting non-melanoma types, skin cancer is the most commonly diagnosed cancer in the UK, and it is also one of the most preventable and, caught early, one of the most treatable. Knowing what to look for turns a vague worry into a simple habit. That is what this guide is for.

What are the symptoms of skin cancer?

Signs worth noticing include:

• A new mole, or a mole that changes in size, shape or colour
• A patch of skin, lump or sore that will not heal after a few weeks
• A spot that itches, bleeds, crusts or becomes scaly
• A shiny, pearly or waxy bump, often on the face or neck
• A sore or rough patch that keeps coming back in the same place

None of these means you definitely have skin cancer, and most turn out to be harmless. But your skin is easy to check and easy to show a doctor, so there is rarely a reason to wait.

What does skin cancer look like?

The ABCDE rule for moles:

• A is for Asymmetry, where one half of the mole does not match the other
• B is for Border, meaning edges that are ragged, blurred or uneven
• C is for Colour, with more than one shade, or new colours appearing
• D is for Diameter, as melanomas are often wider than 6mm, about a pencil rubber
• E is for Evolving, any change in size, shape, colour, or a mole that itches or bleeds

Non-melanoma skin cancers look different. A basal cell carcinoma is often a shiny or pearly bump, while a squamous cell carcinoma can be a firm, scaly or crusty patch, and both may bleed or fail to heal. If a spot ticks any of these boxes, show your GP rather than watching and waiting.

What are the main types of skin cancer?

• Non-melanoma skin cancer, mainly basal cell carcinoma and squamous cell carcinoma. These are very common, tend to grow slowly, and are usually cured with minor treatment.
• Melanoma, which develops in the pigment cells and can spread to other parts of the body if left. Found early, it is very often curable.

Because melanoma is the more serious of the two, much of the advice about checking moles is aimed at spotting it early, when treatment is simplest and most effective. It sits alongside the other cancer types we cover.

What causes skin cancer, and who is at higher risk?

• Ultraviolet exposure, from the sun and especially from sunbeds
• Fair skin that burns easily, freckles, or has red or fair hair
• A history of sunburn, particularly blistering sunburn in childhood
• Having many moles, or unusual moles
• A family or personal history of skin cancer
• A weakened immune system, for example after an organ transplant

People with darker skin get skin cancer less often, but can still develop it, sometimes in less sun-exposed areas such as the soles of the feet, so everyone benefits from knowing the signs.

When should I see my GP about a mole or spot?

Take a photo of anything you are unsure about, so you and your GP can see whether it changes. Your GP may examine it closely with a small magnifier, and if needed will refer you to a skin specialist. Finding skin cancer early usually means simpler treatment and an excellent outcome.

How is skin cancer diagnosed?

• A close examination of the spot, often with a dermatoscope
• A biopsy or excision, removing the area to examine it
• Measuring the depth of a melanoma, which helps predict its behaviour
• Further scans, only if there is a concern the cancer has spread

Most diagnoses happen quickly, and for many non-melanoma skin cancers the same procedure that confirms the diagnosis also removes the cancer completely.

What are the treatments for skin cancer?

• Surgery removes the cancer, and is the main treatment for both melanoma and non-melanoma skin cancer.
• Cryotherapy, creams or curettage can treat some small non-melanoma cancers without cutting.
• Radiotherapy is an option where surgery is difficult.
• Immunotherapy and targeted therapy have transformed the outlook for advanced melanoma in recent years.

For most people with early skin cancer, treatment is a short, minor procedure. Support is available at every step, from your team and from charities such as Macmillan, and our prevention guides share how to protect your skin afterwards.

What do the stages of melanoma mean?

Non-melanoma skin cancers are usually described by type and size rather than these stages, because they rarely spread. Whatever the stage, your team can explain what it means for you, which matters far more than the label.

How can I prevent skin cancer and check my skin?

Simple habits that help:

• Spend time in the shade, especially between 11am and 3pm from March to October.
• Cover up with clothing, a hat and sunglasses.
• Use sunscreen of at least SPF 30 with good UVA protection, and reapply it.
• Never use sunbeds.
• Check your skin every month or two, and show your GP anything new or changing.

No habit removes all risk, and no one who develops skin cancer is to blame. But sun safety and regular checks move the odds a long way, which is the whole idea behind our mission. If in doubt, get it checked, and you can contact us for pointers to trusted support.

Guides like this are free, medically reviewed, and paid for by supporters, not pharma. If yours was useful, there are many ways to help.