Skin Cancer: Symptoms, Causes, Diagnosis & Treatment 

Introduction

Noticing a new mole, a changing spot on your skin, or a sore that does not heal can make you wonder whether it could be skin cancer.  

Skin cancer is a broad group of conditions in which cells and tissues in the skin grow abnormally¹.

Understanding what is skin cancer, skin cancer types, their symptoms, causes, and risk factors, as well as how they are diagnosed and treated, can help you recognise warning signs and aid in early stage skin cancer. Knowing how to protect your skin and when to seek medical advice can also support early detection and better outcomes. 

What Is Skin Cancer?

Skin cancer is a broad group of conditions in which cells and tissues in the skin grow abnormally. A majority of the skin cancer subtypes, such as melanoma, squamous cell carcinoma, and basal cell carcinoma are primarily caused by UV exposure¹. Among these, squamous cell cancer and basal cell cancer are the two most prevalent forms. They typically appear on the hands, arms, neck, head, and face. Melanoma is a less prevalent but more serious kind of skin cancer².

Types of Skin Cancer

The type of skin cancer depends on which type of skin cells become cancerous⁴.

• Squamous cell carcinoma (SCC): Squamous cell carcinoma starts in the squamous cells, which form the topmost layer of the skin.  
• Basal cell carcinoma (BCC): Basal cell carcinoma starts in the basal cells, which are located beneath the squamous cells.  
• Melanoma: It starts in melanocytes, the cells that produce melanin, the pigment responsible for skin colour. Melanoma is less common than basal and squamous cell carcinomas but causes more deaths because it can spread to other parts of the body. 

Signs and Symptoms of Skin Cancer

A change in the skin is the most common sign of skin cancer. Skin cancer symptoms include⁵.

• A new growth: A new growth on the skin may be a sign of skin cancer.  
• A sore that does not heal: A sore that does not heal, particularly one that is crusty or bleeds, can be a sign of basal cell carcinoma.  
• A different colour or textured skin patch: A scaly patch, a firm, skin- or red-coloured bump, or an open sore that bleeds may indicate a squamous cell carcinoma.  
• Changes in a mole or spot: Warning signs of melanoma include an asymmetrical shape, irregular border, uneven colour, a spot or mole with diameter larger than a pea, or a spot or mole that has changed in the previous few weeks to months. 

Causes of Skin Cancer

Skin cancer develops when abnormal changes in skin cells cause them to grow and multiply uncontrollably, with UV radiation being a major cause of many types of skin cancer^1,4. Various skin cancer causes include: 

• UV radiation exposure: Unprotected overexposure to the sun’s ultraviolet (UV) rays can damage the DNA of skin cells and contribute to skin cancer^1,6.
• Artificial UV radiation: Unprotected UV exposure from tanning beds and lamps can damage skin cell DNA and contribute to skin cancer^4,6.
• DNA mutations: Skin cancer can develop when mutations accumulate in the DNA, the basic genetic material of skin cells and promote abnormal cell growth when triggered by factors such as inflammation^1,6. 
• Environmental chemicals: Exposure to certain toxic chemicals can also contribute to skin cancer, including cancer developing in areas not usually exposed to sunlight^1,6. 

Risk Factors for Skin Cancer

Several factors, such as the following, can increase the risk of developing skin cancer: 

• Exposure to UV rays: People with exposure to UV radiation have increased risk of developing skin cancer⁶.
• Fair skin: People with lighter skin have a higher risk of skin cancer^6,7.
• Gender: Basal and squamous cell carcinomas are more common in men than in women⁶.
• Older age: The risk of non-melanoma skin cancer increases with age^1,6.
• Many or unusual moles: Having many, large, or irregular looking moles increases the risk of skin cancer^6,7.
• Weakened immune system: People with weakened immunity are more likely to develop skin cancer^1,6. 
• Living at higher altitudes or in a sunny climate: People living in a sunny climate or at higher altitudes are at increased risk of skin cancer⁶.
• Personal or family history: A personal history of previously having skin cancer or having a parent or sibling with skin cancer increases the risk for skin cancer^1,6.
• Previous radiation treatment: Radiation treatment can increase the risk of skin cancer in the previously treated area^1,6.
• Skin that burns easily, or light-coloured eyes or hair: Characteristics such as skin that burns or freckles easily in the sun, green or blue eyes and red or blond hair, are associated with a higher risk⁷.

Complications of Skin Cancer

Possible complications of skin cancer include¹:

• Local spread: Skin cancer can invade nearby tissues, causing tissue damage and pain.  
• Spread to other parts of the body: Skin cancer may spread to the brain, lungs, lymph nodes, or other areas of the skin.  
• Infection: Skin cancer lesions, particularly ulcerated ones, may become infected.  
• Scarring and tissue damage: Skin cancer may cause scarring, tissue destruction, disfigurement, or physical disability.  
• Pain, itching, or bleeding: Skin cancer may cause pain, itching, bleeding, or discomfort.  
• Recurrence: Skin cancer may return after treatment. 
• Emotional effects: Skin cancer may be associated with anxiety, depression, distress, or fear. 

Diagnosis of Skin Cancer

Skin cancer is diagnosed by examining suspicious skin changes and, when needed, examining a skin sample under a microscope¹.

• Medical history and skin examination: A doctor reviews the clinical history and examines suspicious lesions, including their size, shape, colour, texture, borders, and recent changes^1,8. 
• Dermoscopy: Dermoscopy is a non-invasive examination of a lesion using a special magnifying lens, helping doctors see features that may not be visible to the naked eye. It can help improve the detection of skin cancer and identify it at an earlier stage^1,9. 
• Skin biopsy: If a skin area looks abnormal or suspicious, a biopsy may be performed. The removed tissue is examined under a microscope by a pathologist to check for cancer cells⁸.
• Further tests: If cancer has been diagnosed, imaging such as CT, ultrasound, PET scan, and other evaluations may be used to determine whether it has spread and how far, including staging of skin cancer⁸.

Treatment of Skin Cancer

Treatment depends on the type and stage of skin cancer, the size and location of the tumour, and the person’s overall health⁸. Skin cancer treatment involves⁸:

• Surgery: The cancer is removed surgically, including excisional surgery in which the tumour and some surrounding healthy tissue are removed. 
• Mohs surgery: In this treatment, the tumour is removed layer by layer, with each layer examined under a microscope until no cancer cells remain. 
• Curettage and electrodesiccation: The tumour is scraped away, and an electrical current is used to destroy remaining cancer cells. 
• Cryosurgery: Liquid nitrogen is used to freeze and destroy abnormal tissue. 
• Radiation therapy: High energy radiation is used to kill cancer cells. 
• Medicines: Some skin cancers may be treated with medicines applied to the skin, chemotherapy, targeted therapy, or immunotherapy, depending on the type and stage. 

Prevention of Skin Cancer

Some of the tips to prevent skin cancer include¹⁰:

• Limit sun exposure: Reducing exposure to sunlight is one of the most important ways to protect your skin. Avoid the sun between 10 a.m. and 2 p.m., when UV exposure is at its peak.  
• Use sunscreen: Apply sunscreen to exposed skin when outdoors and reapply every two hours. Use sunscreen that provides broad spectrum protection against UVA and UVB rays. 
• Wear protective clothing: Use a wide brimmed hat, sunglasses, and protective clothing when outdoors. 
• Avoid tanning beds: Artificial UV sources such as tanning beds and sun lamps can increase skin cancer risk. 
• Check your skin: Check for unusual spots, growths, or suspicious moles regularly and consult a doctor if you notice a change in appearance of your existing spots or moles. 

When to Consult a Doctor?

You should seek medical advice if you notice a new or changing skin lesion, particularly one that looks different from your other moles or if its history is concerning. Early evaluation is important to help detect skin cancer early and prevent complications. If a lesion is suspicious, further evaluation such as dermoscopy or a skin biopsy may be needed^1,9.

Also Read: Black Spots on Skin: Causes, Types, Treatment & Prevention

Conclusion

Skin cancer can often be treated successfully when it is diagnosed and treated early. Being familiar with changes in your skin, protecting yourself from UV exposure, and having suspicious or changing spots checked by a dermatologist can support early detection. If you notice a new, changing, or unusual skin lesion, do not ignore it; seek medical advice for appropriate evaluation and treatment. 

Frequently Asked Questions (FAQs)

References

1. Sathe NC, Zito PM. Skin Cancer. In: StatPearls. StatPearls Publishing; 2026. Accessed August 14, 2026. http://www.ncbi.nlm.nih.gov/books/NBK441949/ 

2. Skin Cancer. Accessed August 14, 2026. https://medlineplus.gov/skincancer.html 

3. Skin Cancer: Facts and Stats. Office of Student Life. January 4, 2023. Accessed August 14, 2026. https://geiselmed.dartmouth.edu/students/student-wellness-resources/sun-safety-and-skin-cancer-prevention/skin-cancer-facts-and-stats/ 

4. CDC. Skin Cancer Basics. Skin Cancer. July 6, 2026. Accessed August 14, 2026. https://www.cdc.gov/skin-cancer/about/index.html 

5. CDC. Symptoms of Skin Cancer. Skin Cancer. July 6, 2026. Accessed August 14, 2026. https://www.cdc.gov/skin-cancer/symptoms/index.html 

6. Skin Cancer. Accessed August 14, 2026. https://medschool.cuanschutz.edu/colorado-cancer-center/for-patients-families/cancers-we-treat/skin-cancer 

7. CDC. Skin Cancer Risk Factors. Skin Cancer. July 6, 2026. Accessed August 14, 2026. https://www.cdc.gov/skin-cancer/risk-factors/index.html 

8. Skin Cancer Treatment – NCI. February 10, 2026. Accessed August 14, 2026. https://www.cancer.gov/types/skin/patient/skin-treatment-pdq 

9. Sonthalia S, Yumeen S, Kaliyadan F. Dermoscopy Overview and Extradiagnostic Applications. In: StatPearls. StatPearls Publishing; 2026. Accessed August 21, 2026. http://www.ncbi.nlm.nih.gov/books/NBK537131/ 

10. Skin Cancer. Harvard Health. February 27, 2023. Accessed August 14, 2026. https://www.health.harvard.edu/topics/skin-cancer 

11. CDC. Preventing Sunburn. Skin Cancer. July 6, 2026. Accessed August 21, 2026. https://www.cdc.gov/skin-cancer/prevention/sunburn.html 

12. Common Cancer Myths and Misconceptions – NCI. January 18, 2023. Accessed August 14, 2026. https://www.cancer.gov/about-cancer/causes-prevention/risk/myths 

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