Sun safety and skin cancer prevention

What is it?

Ultraviolet (UV) radiation is a type of radiation that cannot be seen or felt, reaches everyone from the sun, and may also come from artificial sources used in medicine, industry, sterilisation and cosmetics, according to WHO.

WHO says that the level of this radiation increases the higher the sun is in the sky, the closer the place is to the equator, and the higher the altitude, that reflection from water, sand and fresh snow increases exposure, and that clouds do not always block it.

Sunburn is redness of the skin caused by excessive exposure to UV radiation, whether from the sun or other sources, according to MedlinePlus.

There are two main types of skin cancer according to NCI: non-melanoma cancer (which includes squamous cell carcinoma and basal cell carcinoma), and melanoma, which is less common but grows and spreads faster and is harder to treat.

Why it matters

WHO says that excessive exposure to UV radiation causes acute harms such as DNA damage, sunburn, phototoxic skin reactions and photosensitivity, and immune suppression, which is a risk factor for cancer and may reactivate viruses such as those that cause cold sores.

The WHO states that chronic exposure may cause in the long term cutaneous melanoma (a life-threatening cancer), squamous cell carcinoma (less common and usually less dangerous), and basal cell carcinoma (slow-growing and often affecting older people), as well as premature skin ageing marked by loss of elasticity and slow wound healing (see also healthy ageing).

According to WHO's 2020 estimate, more than 1.5 million cases of skin cancer were diagnosed worldwide, and more than 120,000 deaths were recorded from it; of these, about 1.2 million cases were non-melanoma skin cancer and about 325,000 were melanoma, with about 64,000 deaths from non-melanoma and 57,000 from melanoma.

NCI says that skin cancer is the most common cancer in the United States, and that the non-melanoma type is the most common among its types.

UV radiation also harms the eye: WHO lists acute painful but usually reversible harms such as photokeratitis and photoconjunctivitis, and chronic harms such as cataract, pterygium, and cancers in and around the eye, and says the radiation may contribute to age-related macular degeneration. WHO estimates that about 15 million people worldwide have lost their sight due to cataract, and that about 10% of these cases may be attributable to UV radiation.

MedlinePlus says there is no such thing as a "healthy tan", and that the damage UV radiation does to skin cells can be permanent and contributes to skin cancer and premature skin ageing.

Key points

WHO and the CDC recommend sun protection when the UV Index is 3 or above.

According to the CDC, UV radiation is usually strongest in the continental United States between 10 a.m. and 4 p.m. daylight saving time (or 9 a.m. to 3 p.m. standard time), while MedlinePlus gives a similar peak between 10 a.m. and 2 p.m.; the exact hours vary with geographic location and season.

The CDC recommends using a broad-spectrum sunscreen with a sun protection factor (SPF) of 15 or higher, while MedlinePlus recommends SPF 30 or higher, reapplied every 2 hours or according to the label instructions and after swimming or sweating, even on cloudy days; choosing what suits your skin is discussed with your doctor or pharmacist.

WHO advises choosing wrap-around sunglasses that block 99 to 100% of UVA and UVB rays, and the CDC agrees on choosing glasses that block both types.

WHO says that the best way to protect against the sun is to seek shade and wear protective clothing rather than relying on sunscreen alone, and that sunscreen should not be used to prolong time spent in the sun.

However, NCI explains that protecting the skin and eyes from the sun has not been conclusively shown in studies to reduce the risk of skin cancer, but dermatology experts still advise sunscreen, reducing time of exposure, and wearing long sleeves, trousers, hats and sunglasses.

The CDC and WHO warn against artificial tanning beds and booths: the CDC says they do not protect against sunburn and that a "base tan" is a sign of skin damage, not health, and that any tan is a sign of injury, not good health; WHO says they increase the risk of skin cancer and that tanning should never be used to obtain vitamin D.

How to put it into practice

Seek shade: both WHO and the CDC advise staying in the shade, especially during peak hours.

Wear protective clothing: the sources recommend clothing that covers the arms and legs, and a wide-brimmed hat that shades the face, head, ears and neck; MedlinePlus states that light-coloured clothing reflects the sun's rays better.

Protect your eyes: choose wrap-around sunglasses that block UVA and UVB rays, according to WHO, the CDC and MedlinePlus.

Use sunscreen on skin not covered by clothing: choose a broad-spectrum product, apply it generously to all exposed skin including the ears and back of the neck, reapply periodically and after swimming or sweating, even on cloudy days, and use a lip balm containing sunscreen, according to the CDC and MedlinePlus. WHO reminds that sunscreen is an additional option and not a substitute for shade and clothing.

Check the UV index in your area and take protective measures when it reaches 3 or above, according to the CDC and WHO.

Avoid artificial tanning beds and booths altogether, according to the CDC and WHO.

When sunburn occurs: MedlinePlus advises showering or washing with cool water or applying cool, wet compresses, and avoiding products containing benzocaine or lidocaine because they may cause allergy or further irritate the burn. If there are no blisters a moisturiser may help (avoiding butter, petroleum jelly and oil-based products), and creams containing vitamins C and E may help limit cell damage.

For blisters, MedlinePlus advises dry dressings to reduce the risk of infection, and not picking at or peeling blisters. It states that over-the-counter pain relievers such as ibuprofen or paracetamol (acetaminophen) may ease discomfort, with a warning against giving aspirin to children, and that cortisone creams may reduce inflammation. Choosing what suits your condition is decided by the doctor or pharmacist.

Wear loose cotton clothing and drink enough water while recovering from sunburn, according to MedlinePlus.

Special groups

Children: WHO says that children and adolescents are more vulnerable because of the structure of their skin and eyes, that childhood sunburn raises the risk of skin cancer later, and that more radiation reaches the retina of their eyes; it advises encouraging them to follow the same protective measures while enjoying outdoor activities. MedlinePlus describes them, along with infants, as very sensitive to sunburn.

People with fair skin, eyes and hair: the CDC states that risk factors for skin cancer include naturally light skin, skin that burns, freckles, reddens easily or is painful in the sun, blue or green eyes, and blond or red hair. WHO says that people with fair skin burn more easily and are at higher risk, although people with dark skin can also develop skin cancer. MedlinePlus states that very fair skin may burn in under 15 minutes of midday sun, whereas dark skin tolerates the same exposure for hours.

Outdoor workers: WHO says they are more exposed to the sun's rays and that this raises their risk of non-melanoma skin cancer.

People with a personal or family history of skin cancer or a large number of moles: the CDC, NCI and WHO list these among the risk factors, as well as people taking medicines that may increase sensitivity to light (such as some antibiotics like doxycycline and tetracycline according to MedlinePlus) or with weakened immunity (such as those who have had organ transplants and take immunosuppressive medicines according to NCI), or conditions that increase skin sensitivity to the sun such as lupus according to MedlinePlus. Discuss with your doctor the effect of any medicine you take on your sun sensitivity, without stopping it on your own.

People with very limited sun exposure: WHO advises people living in institutional care or who do not leave their homes, people with dark skin at high latitudes, and those who cover all of their skin when outdoors for religious or cultural reasons, to consider oral vitamin D supplements; this is a decision to discuss with the doctor.

Risks and cautions

Symptoms of sunburn according to MedlinePlus: redness, pain and warmth in the skin, which may appear within hours with the full effect developing over 24 hours or more, and pain peaks between 6 and 48 hours after exposure; blisters may appear after hours or days, and the skin peels after several days.

"Sun poisoning": MedlinePlus states that severe reactions to sunburn may include fever, chills, nausea or a rash.

Types of skin cancer: WHO and NCI explain that melanoma is less common but the most dangerous and grows and spreads quickly, whereas squamous cell carcinoma and basal cell carcinoma are more common, although basal cell carcinoma is slow-growing and often affects older people.

Signs that call for an examination by a dermatologist according to MedlinePlus: any suspicious mark on the skin or change in its appearance, and for moles specifically five features that are advised to be watched: asymmetry, irregular borders, multiple colours, large diameter, and elevation above the skin surface.

Eye risks: WHO lists photokeratitis and photoconjunctivitis as acute, painful but usually reversible harms, and cataract, pterygium and cancers of the eye and surrounding area as chronic harms, with possible contribution of the radiation to age-related macular degeneration.

Risks of artificial tanning: the CDC says tanning beds do not protect against sunburn and that a "base tan" is a sign of skin damage, and tanning may cause severe burns and other injuries; WHO stresses that it raises the risk of skin cancer, and that a number of countries restrict or ban it.

Trade-offs regarding prevention: NCI states that sunscreen may sometimes cause allergic skin reactions and may lower vitamin D levels, and may lead some people to stay longer in the sun thinking they are fully protected; avoiding the sun completely may also be associated with mood disorders, sleep problems, high blood pressure and disturbed vitamin D metabolism. It adds that sun protection of the skin has not been shown to protect specifically against UV-induced melanoma, although sunscreens prevent sunburn and actinic keratosis, which can develop into squamous cell carcinoma.

Limits of this information

The exact hours of peak UV radiation differ slightly between sources (10 a.m. to 4 p.m. according to the CDC for the continental United States, and 10 a.m. to 2 p.m. according to MedlinePlus), and actually depend on latitude, season, altitude and your country's time zone; the best practical reference is the local UV index if available.

Recommendations on sun protection factor (SPF) and how often to reapply differ between the sources of this page (15 or higher according to the CDC, and 30 or higher with reapplication every 2 hours according to MedlinePlus); choosing the product and level of protection that suits your skin and region is decided by your doctor or pharmacist.

The sources of this page do not give specific figures on skin cancer rates in the Gulf region or Arab countries, nor national Gulf recommendations on sun protection or vitamin D supplements; the figures cited here are global (WHO) or American (CDC, NCI and MedlinePlus) and may not apply in detail to every country.

This page does not cover the types or amounts of vitamin D supplements or the treatment of skin cancer; it is limited to prevention and general information about sunburn, and what suits your individual condition is decided by your doctor.

The information on children and outdoor workers here comes mainly from WHO.

Common questions