Skin Cancer: Causes & Symptoms You Shouldn’t Ignore

When it comes to skin health, early detection can make all the difference –  and that’s especially true for skin cancer. It remains one of the most common forms of cancer in the UK, and while many types are highly treatable when caught early, they can become dangerous if left unaddressed. Unfortunately, we often see patients who delay seeking help because they’re unsure what to look for or assume a suspicious mark is harmless.

From our experience treating skin cancer in a clinical setting, we know how vital it is to recognise the warning signs and understand the common causes. Awareness leads to early diagnosis – and that leads to better outcomes. Whether you’re concerned about a mole, a patch of dry skin that won’t heal, or a sudden change in pigmentation, it’s important to take your concerns seriously.

In this post, we’re sharing expert insights on what causes skin cancer, how to identify potential symptoms, and when it’s time to seek professional advice. If you have any doubts, we always recommend booking a consultation with one of our dermatologists – we’re here to help.

 

What Causes Skin Cancer?

Skin cancer develops when skin cells are damaged and begin to grow abnormally. The most common cause of this damage is ultraviolet (UV) radiation – primarily from the sun, but also from artificial sources such as tanning beds.

Over time, repeated or intense UV exposure can alter the DNA in skin cells, which leads to mutations and uncontrolled growth. While the body normally repairs minor DNA damage, long-term exposure can overwhelm this process, especially in people with fair skin or a history of sunburn.

Although UV radiation is the leading cause, there are other contributing factors as well:

• Genetics: A family history of skin cancer may increase your risk.
• Skin Type: Fair-skinned individuals are more susceptible to sun damage.
  
• Moles or Atypical Lesions: Having many moles, especially dysplastic (unusual-looking) ones, can be a risk factor.
  
• Weakened Immune System: Immunosuppression  –  whether from illness or medication  –  can increase your vulnerability.
  
• Exposure to Toxins or Radiation: Certain chemicals and environmental exposures may also play a role.
  
  

It’s important to note that skin cancer doesn’t just affect people who sunbathe. Even those who are rarely outdoors can develop it  –  especially if they’ve had intense sun exposure in the past or use sunbeds.

The Different Types of Skin Cancer

We typically see three main types of skin cancer in clinical practice:

1. Basal Cell Carcinoma (BCC)

This is the most common form of skin cancer and also the least likely to spread. BCC often appears as a pearly or waxy bump, a flat flesh-coloured or brown scar-like lesion, or a sore that doesn’t heal. It usually develops in sun-exposed areas such as the face, neck, or scalp.

2. Squamous Cell Carcinoma (SCC)

SCC tends to develop in areas that have had chronic sun exposure and may present as a firm, red nodule or a flat lesion with a scaly, crusted surface. While still treatable, SCC can grow deeper and spread to other areas of the body if left untreated.

3. Melanoma

Melanoma is less common but far more serious. It arises from the pigment-producing cells (melanocytes) and often develops in or near an existing mole. Melanoma can appear anywhere on the body, not just in sun-exposed areas, and is more likely to spread if not caught early.

 

What Are the Symptoms of Skin Cancer?

Skin cancer symptoms can vary depending on the type, but the most common signs to look out for include:

• A new growth or lesion that appears suddenly and continues to grow
  
  
• A sore that doesn’t heal or keeps reopening
  
  
• A lump that bleeds, oozes, or crusts over
  
  
• A patch of red, scaly or rough skin, especially if it itches or is tender
  
  
• A mole that changes in size, shape, or colour
  
  
• A dark streak under a nail, which may be a sign of melanoma
  
  

We always advise paying attention to the ABCDE rule for moles:

• A – Asymmetry
  
  
• B – Border irregularity
  
  
• C – Colour changes
  
  
• D – Diameter greater than 6mm
  
  
• E – Evolving shape, size or symptoms (such as bleeding or itching)
  
  

If you notice any of these changes, particularly over a period of weeks, it’s important to have it checked by a dermatologist. Skin cancer symptoms often mimic benign conditions at first  –  but only a trained eye can reliably tell the difference.

 

Early Diagnosis is Essential

The earlier skin cancer is diagnosed, the easier and more effective the treatment. In our clinic, we use dermatoscopy and biopsy techniques to assess suspicious lesions and ensure an accurate diagnosis.

This allows us to distinguish between harmless moles, pre-cancerous growths, and confirmed malignancies  –  helping you get the right treatment as quickly as possible. In most cases, early-stage skin cancers can be removed with minor surgical procedures, and regular follow-ups will help ensure that no further changes go unnoticed.

The importance of early intervention cannot be overstated. For example:

• Basal cell carcinomas rarely spread but can cause disfigurement if left to grow.
  
  
• Squamous cell carcinomas can become invasive if ignored.
  
  
• Melanomas have a much higher risk of spreading, but are highly treatable when caught early.

If you’re worried about any skin changes, don’t delay. Our skin cancer clinic in London offers expert assessment and management from experienced consultant dermatologists.

 

How Can You Reduce Your Risk?

Prevention starts with protecting your skin from UV radiation  –  but it doesn’t end there. Based on our clinical experience, we recommend the following steps:

• Wear broad-spectrum SPF 30 or higher every day, even in winter.
  
  
• Avoid sunbeds, which emit concentrated UV radiation.
  
  
• Cover up with clothing, hats, and sunglasses during prolonged outdoor exposure.
  
  
• Check your skin regularly, especially areas that are hard to see  –  or ask a partner for help.
  
  
• Book an annual skin check if you have a personal or family history of skin cancer.
  
  

We also advise patients to watch out for actinic keratoses  –  these are rough, scaly patches that can be a precursor to squamous cell carcinoma. These are treatable, but best addressed early.

 

Frequently Asked Questions

Is skin cancer always caused by sun exposure?

Most cases are linked to UV radiation, but not all. Genetics, immune health, and exposure to certain chemicals can also increase your risk.

What does skin cancer look like at the start?

It can look like a spot, mole, or sore that doesn’t heal. Some types appear flat and scaly; others are raised and shiny. Any change should be examined by a dermatologist.

Can darker skin tones get skin cancer?

Yes. Although the risk is lower, people with darker skin can still develop skin cancer, especially acral lentiginous melanoma, which often appears on the palms, soles, or under nails.

Is a mole always a melanoma?

No. Most moles are benign. However, if a mole changes in size, colour, shape or becomes itchy or painful, it’s best to have it assessed.

How do I book a skin check?

You can book an appointment with one of our consultants by visiting our skin cancer services page or contacting our team directly.

 

Prioritise Your Skin Health

Skin cancer can be easy to overlook  –  especially in its early stages  –  but prompt attention makes all the difference. If you’ve noticed something unusual on your skin or simply want peace of mind, we’re here to support you with thorough assessment, personalised care and evidence-based treatment.

Visit our skin cancer clinic to learn more about how we help patients manage skin concerns with expertise, discretion and compassion.