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Causes and prevention - Skin cancer (non-melanoma)

Most skin cancer is caused by ultraviolet (UV) light damaging the DNA in skin cells. The main source of UV light is sunlight.

Sunlight contains 3 types of UV light:

  • ultraviolet A (UVA)
  • ultraviolet B (UVB)
  • ultraviolet C (UVC)

UVA and UVB damage skin over time, making it more likely for skin cancers to develop. UVC is filtered out by the atmosphere so does not harm our skin.

Artificial sources of UV light, such as sunlamps and tanning beds, also increase your risk of developing skin cancer.

Who is at risk of getting non-melanoma skin cancer

You are at a higher risk of getting non-melanoma skin cancer if you:

  • had non-melanoma skin cancer before
  • have fair skin that does not tan easily
  • got sunburnt often over years
  • were in the sun a lot over years - for example, an outdoor worker or you lived in a sunny country
  • have many moles or freckles
  • have irregular-shaped moles
  • used sunlamps and sunbeds
  • take medicine that suppresses your immune system
  • have a condition that suppresses your immune system, such as HIV
  • are 65 or older
  • have a family history of skin cancer

In most cases, non-melanoma skin cancer does not run in families. But research shows that in some families more people than usual get it.

Preventing non-melanoma skin cancer

It's not always possible to prevent non-melanoma skin cancer. But you can reduce your risk of getting it.

What you can do to reduce your risk

Follow the SunSmart 5S rule: slip, slop, slap, seek and slide

  • Slip on clothes that covers your skin such as long sleeves and collared t-shirts.
  • Slop on broad spectrum (UVA/UVB) sunscreen on exposed skin, using factor 30+ for adults, 50+ for children and reapply regularly.
  • Slap on a wide-brimmed hat to protect your face, ears and neck.
  • Slide on wraparound sunglasses with UV protection to protect your eyes.
  • Seek shade especially if outdoors between 11am and 3pm - and always use a sunshade on a child’s buggy.


  • do not use sunbeds

  • do not try to get a suntan

  • do not get sunburnt

Check the UV index

The UV index tells you how strong the sun’s UV rays are each day.

You need to protect your skin when the UV index is 3 or above.

In Ireland, UV is usually 3 or above from April to September, even when it is cloudy. UV is usually strongest between 11am and 3pm.

Check the UV index on Met Éireann

Check for skin changes

Checking your skin for signs of skin cancer can help you get an early diagnosis. Skin cancer is highly treatable if found early.

Page last reviewed: 20 September 2023
Next review due: 20 September 2026