Ultraviolet (UV) radiation is a type of natural energy from the sun. Scientists know that prolonged exposure to UV rays increases a person’s risk of getting skin cancer.
Sunlight is essential for human health. When it hits a person’s skin, it triggers a reaction that makes vitamin D. Vitamin D helps with calcium absorption and bone growth.
However, UV rays can damage the skin. According to the Centers for Disease Control and Prevention (CDC), most skin cancers are the result of overexposure to UV rays from the sun, tanning beds, or sun lamps.
Here, we explain how UV radiation can damage the skin. We also highlight steps people can take to reduce their risk and explain what symptoms to look out for.
What is UV Radiation?
UV radiation is a type of energy from the sun. According to the United States Environmental Protection Agency, there are three types of UV rays:
- Ultraviolet A, or UVA: This type makes up most of the UV radiation on Earth. These rays cause skin aging and can damage a person’s eyes
- Ultraviolet B, or UVB: These rays cause sunburn and can damage skin cells’ DNA. UVB rays are responsible for most skin cancers.
- Ultraviolet C, or UVC: The earth’s atmosphere blocks these rays. However, scientists can recreate them. Their uses include UV sanitizing light bulbs and arc welding torches.
How does UV radiation cause cancer?
Prolonged UV exposure can cause cancer. The damage builds up over time.
According to the American Cancer Society (ACS), UV rays can damage skin cells’ DNA. Damaged DNA can make cells grow and reproduce uncontrollably, leading to cancer.
Skin cancers start in the top layers of the skin. The names of various types of skin cancer reflect the cells they affect. These include:
- squamous cell carcinoma
- basal cell carcinoma
- melanoma
Basal cell carcinoma is the most common type of skin cancer. It usually occurs on a person’s arms, head, or neck — parts of the body that many people expose to sunlight. However, basal cell carcinoma can form anywhere on the body.
Squamous cell carcinomas also develop on areas of exposed skin. The face, neck, arms, chest, rim of the ear, and back are common sites.
Melanomas begin in cells called melanocytes. When UV rays hit a person’s skin, they stimulate these cells to make melanin. Melanin is the skin’s pigment, and increased amounts darken or tan the skin.
When to see a Medical Provider
Not all skin cancers look alike. However, a new mole or a sore that will not heal can be a symptom of skin cancer. If you are concerned about skin changes, you should consult a dermatologist.
We recommend following the ABCDE rule when checking unusual blemishes or moles for symptoms of melanoma:
- A for asymmetry: The shape of one half is not the same as the other half.
- B for border: The border is ragged, notched, or blurred. The pigment may spread and be noticeable in the surrounding skin.
- C for color: The coloring differs from one area to the next, with shades of black, brown, and tan. Some areas may also appear white, gray, red, pink, or blue.
- D for diameter: The marking has changed size — it is particularly of concern if it has gotten bigger. Most melanomas are larger than 6 millimeters or 1/4 inch wide, which is about the width of a pencil eraser. However, they can be smaller than this.
- E for evolving: The marking changes shape, size, or color over a couple of weeks or months.
