Skin Cancer: Symptoms, Causes, Stages, Diagnosis, Treatment and Early Warning Signs

Skin cancer is one of the most common types of cancer, but it is also one of the cancers that can often be noticed early because it develops on the skin. A new growth, changing mole, persistent sore, unusual patch or bleeding spot may be the first clue that something needs medical attention.

The good news is that many skin cancers are highly treatable when detected early. However, not all skin cancers behave in the same way. Basal cell carcinoma and squamous cell carcinoma are common and generally grow more slowly, while melanoma is less common but has a greater ability to spread to other parts of the body.

Knowing what to look for can make a real difference. Regularly examining your skin, protecting it from excessive ultraviolet (UV) exposure and getting suspicious changes checked by a doctor are important parts of skin cancer awareness.

What is skin cancer?

Skin cancer develops when abnormal cells in the skin begin growing uncontrollably. The three major types are basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and melanoma. There are also less common forms, including Merkel cell carcinoma.

BCC and SCC are collectively often referred to as non-melanoma skin cancers. They are usually associated with cumulative UV exposure and commonly develop on sun-exposed skin.

Melanoma begins in melanocytes, the cells responsible for producing melanin. Although melanoma accounts for a much smaller proportion of skin cancer cases than BCC or SCC, it is more likely to invade deeper tissues and spread to distant organs. The National Cancer Institute notes that most deaths from skin cancer are caused by melanoma.

How does skin cancer start?

Skin cancer starts when changes occur in the DNA of skin cells, causing them to grow and divide abnormally. UV radiation from sunlight, sunlamps and tanning beds is a major contributor, although UV exposure is not the only factor involved.

Repeated sun exposure and sunburn can gradually damage skin cells. Over time, accumulated damage can contribute to cancerous changes.

Other factors that can increase risk include:

• Fair or light skin
• Light-coloured eyes
• Blonde or red hair
• Freckled skin
• A history of repeated sunburn
• Regular or prolonged sun exposure
• Use of tanning beds
• Having many moles or atypical moles
• A family history of melanoma or other skin cancers
• Previous skin cancer
• A weakened immune system
• Certain inherited conditions

However, skin cancer can affect people of every skin tone. People with darker skin are less likely to develop some types of skin cancer, but when melanoma occurs, it may appear in less obvious areas such as the palms, soles and nail beds.

What does the beginning stage of skin cancer look like?

There is no single appearance that defines early skin cancer.

In its beginning stage, skin cancer may look like:

• A new mole or unusual spot
• A small shiny or pearly bump
• A rough or scaly patch
• A persistent sore that does not heal
• A spot that repeatedly crusts or bleeds
• A firm growth
• A mole that changes in size, shape or colour
• A dark streak under a fingernail or toenail
• A patch that looks noticeably different from other spots on your skin

An early melanoma may resemble an ordinary mole, which is why changes over time are important. The ABCDE rule can help identify suspicious pigmented lesions.

Importantly, not every unusual-looking spot is cancer. Eczema, warts, harmless moles, infections and many other skin conditions can look concerning. Only a medical evaluation can determine what a suspicious lesion actually is.

What symptoms are skin cancer?

Skin cancer symptoms vary according to the type.

Common warning signs include:

• A new growth on the skin
• A sore that does not heal
• A sore that heals and then returns
• A rough, scaly or crusted patch
• A shiny or pearly bump
• A firm, dome-shaped growth
• A mole that changes
• A spot that bleeds or oozes
• A lesion that becomes painful or tender
• Persistent itching around a skin growth
• A dark line or patch under a nail

Mayo Clinic also lists changes in the size, colour or appearance of a mole, as well as itching or pain around a skin growth, among possible signs of skin cancer.

One important point: skin cancer does not always cause symptoms. A lesion can be painless and still require investigation.

How does stage 1 skin cancer look like?

Stage 1 skin cancer does not have one specific visual appearance.

In melanoma, stage 1 means the cancer is still confined to the skin but has become invasive. Its appearance may still be a relatively small pigmented spot or mole with changes in asymmetry, border, colour or size.

Basal cell and squamous cell carcinomas have their own staging systems, and their appearance can vary depending on location and tumour characteristics.

This is why you cannot determine the stage of skin cancer simply by looking at it. Staging depends on pathology and, when necessary, additional investigations.

Is skin cancer itchy?

It can be. But itching alone does not mean that a spot is cancerous.

Some skin cancers can itch, bleed, become painful or feel tender. Melanoma, for example, may sometimes itch or become painful, particularly as it changes or becomes more advanced.

Persistent itching becomes more concerning when it occurs alongside a visible change such as:

• A growing spot
• A changing mole
• Bleeding
• Crusting
• A non-healing sore
• A new unusual growth

If a spot continues to change, it is better to have it assessed rather than assuming it is simply an itchy rash.

How to identify skin cancer early?

Early detection starts with knowing what is normal for your skin.

Look for anything new, unusual or changing. For moles and pigmented spots, use the ABCDE approach:

A – Asymmetry: One half does not resemble the other.

B – Border: The edges are irregular, jagged, scalloped or poorly defined.

C – Colour: The lesion contains multiple colours or develops an unusual colour.

D – Diameter: Melanomas are often larger than 6 mm when diagnosed, although they can be smaller.

E – Evolving: The spot changes in size, shape, colour or appearance over time.

The E for evolving is particularly important. A spot that looks different from your other moles or changes over weeks or months deserves attention.

Also remember that skin cancer can occur without following the classic ABCDE pattern. A persistent sore, scaly patch or new growth can also warrant medical assessment.

How to check for skin cancer at home?

A monthly skin self-check can help you notice changes early.

Stand in front of a full-length mirror and examine the front and back of your body. Then check both sides with your arms raised.

Do not forget less obvious areas:

• Scalp
• Behind the ears
• Neck
• Back
• Underarms
• Arms and forearms
• Palms
• Between fingers
• Fingernails
• Legs
• Between the toes
• Soles of the feet
• Toenails
• Buttocks
• Genital area

Use a hand mirror or ask someone you trust to help examine areas that are difficult to see. Taking photographs of moles can also help you compare them over time.

People with darker skin should pay particular attention to the palms, soles, fingers, toes and nail beds, because melanoma can occur in these areas and may be overlooked.

A home skin check is useful for finding changes, not diagnosing cancer. If something looks suspicious, a dermatologist or other qualified doctor should examine it.

Where is most skin cancer found?

Most skin cancers develop on areas that receive substantial sun exposure, including:

• Face
• Scalp
• Ears
• Neck
• Lips
• Arms
• Back of the hands
• Legs

Mayo Clinic notes that the scalp, face, lips and ears are among the common locations.

However, skin cancer can also occur in areas that receive little or no sunlight. This includes the palms, soles, genital area and skin beneath or around the nails. This is particularly important for people with darker skin.

What age is skin cancer common?

The risk of skin cancer generally increases with age because UV-related skin damage accumulates over many years. However, skin cancer can occur at almost any age.

Melanoma is also seen in younger adults. According to the American Cancer Society, the average age at melanoma diagnosis is around 67, but melanoma can occur in people younger than 30 and is among the more common cancers in younger adults.

So, age should never be used as a reason to ignore a suspicious skin change.

Is skin cancer a serious cancer?

It can be, but the seriousness depends greatly on the type and stage.

Basal cell carcinoma usually grows slowly and rarely spreads to distant parts of the body, although untreated BCC can grow deeply and damage surrounding tissue.

Squamous cell carcinoma can also be highly treatable when detected early but has a greater potential to spread than BCC.

Melanoma is particularly concerning because it can invade deeper tissues and metastasise. The earlier melanoma is detected, the better the chances of successful treatment.

Does skin cancer spread quickly?

Some skin cancers spread very slowly, while others can spread more aggressively.

BCC rarely spreads to distant organs, although it can cause significant local destruction if ignored.

SCC can sometimes spread to nearby lymph nodes or other parts of the body, particularly when it has high-risk features.

Melanoma can spread beyond the original skin lesion to lymph nodes and distant organs. The speed of progression varies from person to person and depends on tumour biology, thickness, ulceration, location and stage.

Therefore, there is no single answer to how quickly skin cancer spreads. A suspicious lesion should be evaluated rather than waiting to see what happens.

How do doctors confirm skin cancer?

A doctor usually begins with a detailed examination of the suspicious area and may use a dermatoscope, which provides a magnified view of the skin.

However, looking at a lesion is not enough to definitively diagnose skin cancer.

A skin biopsy is required for confirmation. During a biopsy, the doctor removes part or all of the suspicious tissue and sends it to a laboratory. A pathologist examines the tissue under a microscope to determine whether cancer cells are present and, if so, what type of cancer it is.

Depending on the suspected cancer, further tests may be needed to determine whether it has spread and to establish its stage.

How is skin cancer treated?

Treatment depends on the type, size, location, depth and stage of the cancer.

Possible treatments include:

• Surgical excision
• Mohs surgery
• Curettage and electrosurgery
• Cryotherapy for selected lesions
• Prescription topical treatments for certain superficial cancers
• Radiation therapy
• Immunotherapy
• Targeted therapy
• Other systemic treatments for advanced disease

For many early skin cancers, surgery can completely remove the cancer and may be the only treatment required.

Advanced melanoma may require immunotherapy, targeted therapy, surgery, radiation or combinations of treatments depending on the individual situation.

Can skin cancer be fully removed?

Yes, many skin cancers can be completely removed, particularly when they are diagnosed early.

The goal of treatment for localized skin cancer is usually complete removal of the cancer while preserving as much healthy tissue as possible.

After surgical removal, the tissue and surrounding margins may be examined under a microscope to check whether cancer cells remain. If the margins are clear, treatment may be complete.

However, no doctor can guarantee that every skin cancer will be permanently cured. Some cancers can recur, and melanoma that has spread requires more complex treatment.

Is skin cancer 100% curable?

No cancer can honestly be described as 100% curable in every patient.

That said, many skin cancers have an excellent prognosis when detected and treated early. Cleveland Clinic notes that nearly all skin cancers can be cured when treated before they have a chance to spread.

For melanoma, current SEER data show a five-year relative survival of 100% for localized melanoma, although survival falls when melanoma has spread regionally or distantly.

These figures are population statistics, not predictions for an individual patient.

How does stage 4 skin cancer look like?

There is no specific appearance that tells you a skin cancer is stage 4.

Stage 4 means the cancer has spread to distant parts of the body. In melanoma, this can include distant lymph nodes, lungs, liver, brain, bones, soft tissues or other organs.

The original skin lesion may appear as a changing mole, dark growth, lump, bleeding lesion or other abnormal spot. There may also be additional symptoms caused by metastatic disease, depending on where the cancer has spread.

Importantly, you cannot diagnose stage 4 skin cancer from the appearance of the skin alone. Imaging, biopsies and other tests may be needed.

Can I survive stage 4 skin cancer?

Yes. Stage 4 skin cancer is serious, but survival is possible, and treatment has improved significantly.

For metastatic melanoma, treatment may include immunotherapy and targeted therapy, among other approaches.

Current SEER statistics show a five-year relative survival of approximately 34% for melanoma with distant spread, although survival statistics vary according to the stage definition, time period, treatments available and individual characteristics.

A person diagnosed with stage 4 melanoma should therefore not assume that the diagnosis means there is no treatment available.

Can skin cancer cause death?

Yes, skin cancer can cause death, particularly when an aggressive cancer such as melanoma spreads to distant organs.

The good news is that deaths from melanoma have declined with advances in treatment, including modern immunotherapies and targeted treatments.

This is one reason early detection matters so much. A suspicious lesion that is found while still localized can often be treated far more successfully than cancer that has already metastasised.

How long will a person live with skin cancer?

There is no single life expectancy for someone with skin cancer.

Prognosis depends on:

• Type of skin cancer
• Stage at diagnosis
• Tumour thickness and depth
• Whether lymph nodes are involved
• Whether distant organs are involved
• Location of the cancer
• Overall health
• Response to treatment
• Whether the cancer returns

For example, localized melanoma has a much more favourable prognosis than metastatic melanoma. SEER reports five-year relative survival of 100% for localized melanoma, compared with 34% for distant-stage melanoma in its current dataset.

These numbers should not be interpreted as an individual’s expected lifespan. Your treating specialist can provide a more meaningful assessment based on your pathology and staging results.

When should you see a doctor?

Make an appointment if you notice:

• A new or unusual skin growth
• A mole that changes
• A spot that keeps getting bigger
• A lesion with several colours
• An irregular border
• A sore that does not heal
• Repeated bleeding or crusting
• A persistent itchy or painful lesion
• A dark streak under a nail
• A new unusual mark on the palm or sole

You do not need to wait until a spot becomes painful. Many early skin cancers are painless.

How can skin cancer be prevented?

You cannot eliminate every risk, but you can reduce UV-related risk considerably.

Practical steps include:

• Use a broad-spectrum sunscreen with SPF 30 or higher.
• Reapply sunscreen as directed, particularly during prolonged outdoor exposure.
• Wear protective clothing and a wide-brimmed hat.
• Use sunglasses that provide UV protection.
• Seek shade when the sun is strongest.
• Avoid tanning beds and artificial tanning lamps.
• Avoid deliberate tanning and repeated sunburn.
• Check your skin regularly.
• Get suspicious or changing lesions examined promptly.

UV radiation can damage skin regardless of whether you visibly burn, so sun protection is relevant for all skin tones.

Frequently asked questions about skin cancer

What does the beginning stage of skin cancer look like?

It can appear as a new growth, persistent sore, rough patch, unusual bump or changing mole. Early melanoma may resemble an ordinary mole but show changes in asymmetry, border, colour, diameter or evolution.

What symptoms are skin cancer?

Common symptoms include a new growth, changing mole, non-healing sore, rough or scaly patch, bleeding, crusting, itching or pain. Some skin cancers have no symptoms at all.

Is skin cancer a serious cancer?

It can be. BCC and many SCCs are highly treatable, especially when caught early. Melanoma is more likely to spread and can be life-threatening when advanced.

How to identify skin cancer early?

Perform regular skin self-checks and look for new, changing or unusual spots. Use the ABCDE rule for suspicious moles and have concerning changes examined by a dermatologist.

Is skin cancer 100% curable?

No cancer is 100% curable in every person. However, many skin cancers, particularly those found early, can be completely treated.

How does stage 4 skin cancer look like?

There is no specific visual appearance of stage 4 skin cancer. Stage 4 refers to cancer that has spread to distant parts of the body, so staging cannot be determined simply by looking at a skin lesion.

How to check for skin cancer at home?

Examine your entire skin, including the scalp, ears, back, palms, soles, nails and areas that are difficult to see. Take photographs of suspicious moles to monitor changes, but consult a doctor for diagnosis.

How does skin cancer start?

It begins when abnormal skin cells acquire changes that allow them to grow uncontrollably. UV radiation is an important cause, although genetics, immune status and other factors also contribute.

Is skin cancer itchy?

It can be, but itching is not specific to skin cancer. An itchy spot that also changes, bleeds, grows or fails to heal should be examined.

Can skin cancer cause death?

Yes. Advanced skin cancer, particularly metastatic melanoma, can be fatal. Early diagnosis substantially improves the chances of successful treatment.

Where is most skin cancer found?

It is commonly found on sun-exposed areas such as the face, scalp, ears, neck, arms, hands and legs. Melanoma can also occur on the palms, soles and under the nails.

What age is skin cancer common?

Risk generally increases with age, but skin cancer can occur in younger adults and even children. Melanoma can occur in people under 30 as well.

How does stage 1 skin cancer look like?

Stage 1 melanoma may look like a relatively small changing mole or unusual pigmented lesion. However, stage cannot be determined by appearance alone and requires medical assessment.

How do doctors confirm skin cancer?

A suspicious lesion is examined clinically and may be assessed with dermoscopy. A skin biopsy examined under a microscope is required to confirm skin cancer.

Does skin cancer spread quickly?

It depends on the type. BCC generally grows slowly and rarely spreads, whereas melanoma can spread more readily. The risk and speed of spread vary between individual cancers.

Can skin cancer be fully removed?

Many localized skin cancers can be completely removed with appropriate treatment. Early detection makes complete treatment more likely.

How long will a person live with skin cancer?

There is no universal answer. Prognosis depends mainly on the cancer type, stage, spread, overall health and response to treatment.

Can I survive stage 4 skin cancer?

Yes. Stage 4 skin cancer is serious, but treatments such as immunotherapy and targeted therapy have changed the outlook for many people with advanced melanoma. Individual prognosis varies considerably.

Final thoughts

Skin cancer is not always dramatic or easy to recognise. Sometimes it begins as a tiny spot that looks like an ordinary mole, a rough patch, a shiny bump or a sore that simply refuses to heal.

That is why knowing your own skin is so important.

Regular self-examination, sensible sun protection and timely medical evaluation can help identify suspicious changes before they become more difficult to treat. And if you notice something unusual, do not try to diagnose it from a photograph or online image alone.

A dermatologist or qualified healthcare professional can examine the lesion and, when necessary, perform a biopsy to establish the diagnosis.

Early detection can make a significant difference in skin cancer treatment and outcomes.

This article is intended for general health education and does not replace examination or diagnosis by a qualified healthcare professional.