Sunburn is damage to the skin occurring as a result of exposure to the sun's ultraviolet (UV) rays. Sunburn is usually noticeable within three hours after exposure and results in red, painful skin that may feel warm to the touch. The condition generally takes several days to heal and may result in blistering or peeling of the skin. Sun exposure, especially repeated experiences of sunburn, can lead to certain diseases of the skin including skin cancer.
Sunburn, which occurs after exposure to the sun's UV rays, most often results in first-degree burning of the skin. In first-degree sunburn, pain, redness, and some swelling may be experienced, and the skin may feel warm when touched. The symptoms of second-degree sunburn may result after more prolonged sun exposure and when negligible or no sunscreen has been used to prevent sun damage. The symptoms of second-degree sunburn include the symptoms of first degree (pain, redness, swelling, hot to the touch) wherein the symptoms are more severe and include blistering of the skin. In seconddegree sunburn, deeper layers of the skin including nerve endings have been damaged. This degree of sunburn takes longer to heal than first-degree burning.
Sunburn is used to describe a condition resulting in exposure to the sun's natural UV rays, or to artificial UV rays experienced after exposure to sunbed tanning lamps. Sunbeds are artificial tanning devices that may offer a supposedly faster, safer alternative to more dangerous natural sunlight; however, research indicates that the UV radiation exposure acquired from sunbed tanning still leads to skin damage, and can contribute to skin cancer.
Sometimes the term “sun poisoning” is used, however the sun does not actually poison the skin. Sun poisoning refers to a very severe case of sunburn in which overexposure to ultraviolet radiation causes all the symptoms of sunburn (redness, pain, swelling, warmth, blistering) along with fever, chills, headache, nausea, and/or dizziness. Dehydration is also a common factor in severe cases of sunburn, or “sun poisoning.”
Beyond pain, redness, swelling, warmth-to-the-touch, and blistering, UV radiation can lead to other physical complications. Repeated UV exposure leads to aging, spotting, and wrinkling of the skin, known as photoaging. Skin spots—also called age spots, liver spots, or solar lentigines—result after years of prolonged ultraviolet light exposure when the melanin of the epidermis becomes clustered together, or is produced by skin cells in high concentrations.
A condition known as actinic keratosis—or solar keratosis—may arise after repeated sun or UV exposure. An actinic keratosis is a rough, dry, scaly, or warty patch of skin usually appearing on the face, hands, arms, or shoulders—areas of the body most exposed to the sun. An actinic keratosis usually begins as a small spot or patch and generally takes several years to develop. These patches are usually treated as precancerous, however, as they frequently result in malignancy.
Damage to the eyes is a complication of exposure to ultraviolet light, either by sunlight or tanning beds or bulbs. Inflammation to the cornea, known as photokeratitis, and inflammation to the conjunctiva, called photoconjunctivitis, may result. These conditions are usually temporary and can easily be prevented with protective eyewear such as UV-filtered sunglasses.
Another consequence of UV radiation overexposure on the eyes is pterygium, a condition in which thickened conjunctiva grows from the inner side of the eyeball usually covering part of the cornea. The mass of conjunctiva is usually fleshy and creamy in nature and results in inhibited vision.
Overexposure to ultraviolet radiation has been linked to immune suppression. Low doses of UV-B exposure can compromise the immunological response of animals and humans, and excessive UV-B exposure can lead to overall immunological suppression. When immunity is compromised by ultraviolet radiation, the skin's ability to respond to allergic triggers and other compromising factors are limited. People with the herpes simplex virus experience a greater number of outbreaks of cold sores after exposure to UV radiation.
The leading cause of skin cancer is exposure to UV radiation, especially a history of repeated or prolonged exposures. Sun overexposure in childhood and adolescence is linked to the occurrence of skin cancer later in life. The World Health Organization reports that one in three diagnosed cancers is a skin cancer; the most fatal of these is malignant melanoma.
Skin cancers are classified under two types: melanomas and nonmelanomas. Melanomas are formed when changes occur to melanocytes—cells of the epidermis responsible for the production of melanin. Basal cell carcinoma is linked to ultraviolet radiation and is a nonmelanoma. It is the most common form of skin cancer in the U.S., where, according to the American Cancer Society, 75% of all cases of skin cancer are basal cell carcinomas.
The majority of basal cell carcinomas occur on areas of the skin that commonly receive sun exposure— the face, neck, forearms, shoulders, tops of the hands, or scalp. These skin cancers are slow-growing and painless and develop in the epidermis, or top cell layer of the skin. Basal cell carcinomas may appear as a new skin growth that does not heal or that bleeds frequently or easily.
At one time basal cell carcinomas were common in people over age 40, but now they are appearing in younger people. People with fair skin, light-colored eyes (blue or green), blonde or red hair, or who are frequently exposed to x-ray radiation may be at a higher risk for these skin cancers. Basal cell skin cancer rarely metastasizes; however, if left too long untreated, it may spread into surrounding tissue or even bone.
Another type of nonmelanoma skin cancer that is linked to UV radiation exposure is squamous cell carcinoma. In its earliest stages, squamous cell carcinoma is called Bowen's disease, or squamous cell in situ. In this stage, it has not yet spread to surrounding tissues. Actinic keratosis is a flaky, patchy, or warty skin lesion that can also lead to squamous cell carcinoma.
Melanoma is the most dangerous form of skin cancer and accounts for the leading cause of death among diseases of the skin. Melanomas are formed when changes occur to melanocytes—cells of the epidermis responsible for the production of melanin. Melanomas may occur in normal-appearing skin or in moles or other skin areas that have changed shape or appearance over time. More infrequently, melanomas can appear in the iris of the eye, the retina, or other areas inside the body. People most at risk for melanomas are the same individuals as those at risk for nonmelanomas, but all people can get this or other types of skin cancer.
Once sunburn has occurred, there is no treatment that can successfully remedy it, but there are measures that can be taken to help soothe the discomfort and help the healing process.
It is important to remember that peeling skin may still be sensitive and to treat it gently. Attempting to rush the peeling process may cause tearing of new skin and may lead to infection. Also, blisters should be left alone or covered in gauze. Attempting to break or squeeze blisters interferes with the body's natural healing process and may lead to infection.
Basal cell carcinomas are treated most frequently by types of surgical excision, or they may be frozen or irradiated. Squamous cell cancers are treated in the same manner as basal cell carcinomas; however, Bowen's disease—early-stage squamous cells—may be treated with photodynamic therapy, wherein a combination of photosensitizing medication and a light therapy are used to kill cancer cells.
Whenever going outdoors, summer or winter, one should protect skin from ultraviolet radiation with the use of protective sunscreen of at least a factor of 15, although a sun protection factor (SPF) of 30 or above is recommended. When going outdoors, apply sunscreen liberally and often to all areas of the body, especially those areas that will be in direct sunlight. Wear protective sunglasses—those shades with UV filtering. Limit the amount of time you will spend in sunlight, and stick to the shade whenever possible. Avoid tanning beds, as the ultraviolet radiation from the bulbs in these beds does contribute to skin damage like burning, aging, and wrinkling, as well as all types of skin cancer.
See also Dehydration .
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Julie Jordan Avritt