Skin cancer: warning signs, sun safety and when to get checked

Most skin cancers are linked to ultraviolet light, which comes from the sun and from sunbeds, and the CDC says daily sun protection lowers the risk. Knowing what to look for and how to protect your skin matters. This article uses information from the NHS and the US Centers for Disease Control and Prevention (CDC).

1. Introduction

The NHS describes melanoma as a more serious skin cancer that often begins as a new mole or a change in an existing mole, while the other common types, basal cell and squamous cell cancers, usually appear as a growth or unusual patch on the skin ^{[1, 3]}. The CDC says that most skin cancers result from too much ultraviolet (UV) exposure from the sun and from tanning beds ^[6].

2. Causes and risk factors

The NHS says UV light is the most common cause of melanoma. It is more common in older people, but younger people can also develop it ^[2]. The NHS lists these risk factors ^[2]:

• Pale skin that burns easily
• Red or blonde hair, or blue or green eyes
• Many freckles or moles
• Significant sun exposure, especially frequent sunburn
• Frequent sunbed use
• A family history of skin cancer, or a previous skin cancer

People with brown or black skin have a lower risk but can still get melanoma. In these people it most often appears on the soles of the feet, the palms of the hands or under a nail ^[2].

3. Warning signs

Moles and melanoma

The NHS says to check your skin regularly, using a mirror or asking someone to look at areas you cannot see. Compared with a usual mole, melanoma is more likely to have ^[1]:

• an uneven shape, with two halves that look different or uneven edges
• two or more colours
• a larger size, often more than 6 millimetres across, although early melanomas can be smaller
• changes over time in size, shape or colour
• swelling, soreness, bleeding, itching or crusting

Rarer types can affect the eyes, the soles of the feet, the palms of the hands or the genitals ^[1].

Other skin cancers

Non-melanoma skin cancers such as basal and squamous cell cancers commonly appear on the head, face, ears, neck, shoulders, back, hands and lower legs. They can look like raised smooth growths, rough or crusty growths, flat discoloured patches, or dry, crusty patches that may itch. Colours may look darker on brown or black skin ^[3].

4. Diagnosis

A doctor will ask about your health, family history and any past skin cancer, and will look at the area. The area may be photographed and sent to a dermatologist, a doctor who specialises in skin. You may be referred urgently for tests or to a hospital specialist. The NHS notes that an urgent referral does not definitely mean you have cancer ^[1].

5. Treatment

Treatment depends on where the cancer is, whether it has spread and your general health, and your care team decides what is right for you ^[4]. For melanoma the NHS describes ^[4]:

• Surgery, the main treatment, especially when found early, which removes the melanoma with a margin of healthy skin
• Radiotherapy, which uses radiation to shrink large melanomas or ease symptoms
• Targeted medicines and immunotherapy, which aim to slow or kill cancer cells or help the immune system do so, for melanomas that cannot be removed or have spread
• Chemotherapy, sometimes used for advanced melanoma
• Palliative care, to control symptoms and provide support when the cancer cannot be controlled

Regular check-ups take place during and after treatment ^[4].

6. Prevention and sun safety

There is no safe or healthy way to get a tan, according to the NHS ^[5]. The CDC says a suntan is a sign of skin injury, and a base tan does not protect against sunburn ^[6]. Both sources recommend a combination of measures ^{[5, 6]}:

1. Spend time in the shade, especially during the strongest sun, which in the UK is between 11am and 3pm from March to October ^[5] and in the continental US is 10 a.m. to 4 p.m. daylight saving time ^[6]. Check the UV index and take care when it is 3 or higher ^{[5, 6]}.
2. Cover up with a wide-brimmed hat, long sleeves and trousers or skirts, and wear sunglasses that block UV rays ^{[5, 6]}.
3. Use broad-spectrum sunscreen, which protects against both UVB and UVA rays. The NHS recommends at least SPF 30 with at least 4-star UVA protection, and the CDC recommends at least SPF 15 ^{[5, 6]}.
4. Apply plenty. The NHS says most people use too little, and advises reapplying about every two hours and after swimming, sweating or towel drying ^[5].
5. Avoid sunbeds and tanning booths ^[6].

Sunscreen alone is not enough, so use it together with shade and clothing ^[5]. UV rays reach you on cloudy and cool days and reflect off water, sand, cement and snow ^[6].

7. Special groups

Children's skin is more sensitive, and repeated sun exposure in childhood can lead to skin cancer later in life. The NHS advises keeping babies under 6 months out of strong direct sun and covering children with clothing, shade and sunscreen ^[5]. The NHS says people with brown or black skin have a lower skin cancer risk because of natural UV protection, but they can still burn and get skin cancer ^[5].

If you get sunburn, the NHS suggests cooling the skin with water, using a soothing aftersun, and staying out of the sun until redness has gone. Seek medical help if you feel unwell, the skin swells badly or blisters form ^[5].

8. When to see a doctor

The NHS advises seeing a GP, a family doctor, if ^{[1, 3]}:

• a mole has changed in size, shape or colour, or is painful, itchy, inflamed, bleeding or crusty
• a new or unusual skin mark has not gone away after a few weeks, including on the palms or soles
• there is a dark area under a nail that was not caused by an injury
• a skin growth is getting bigger or has changed in colour or texture
• an area of skin hurts, itches, bleeds, crusts or scabs for more than 4 weeks

In an emergency, call your local emergency number (112 in India, 911 in the United States).

9. Conclusion

Skin cancer is mainly linked to UV light, and finding it early can make treatment easier. Regular skin checks, prompt medical advice about changing moles or non-healing skin areas, and consistent sun safety are the most useful steps. Your doctor decides on tests and treatment.