You know sunburn when it happens: red, painful skin that feels hot to the touch. Sunburn usually appears within a few hours after sun exposure and may take from several days to several weeks to fade.

What is it?

You know sunburn when it happens: red, painful skin that feels hot to the touch. Sunburn usually appears within a few hours after sun exposure and may take from several days to several weeks to fade.

Intense sun exposure that results in sunburn increases your risk of certain complications and related skin diseases. These include dry, wrinkled skin; liver spots; actinic keratoses; and skin cancer, including melanoma.

You can prevent sunburn and the related skin conditions by protecting your skin whenever you're outdoors, even on cloudy days. If you do get sunburn, several home remedies and treatments can relieve your pain and speed the healing of your skin.

Symptoms

Signs and symptoms of sunburn include:

  • Pinkness or redness
  • Skin that feels warm or hot to the touch
  • Pain or tenderness
  • Swelling
  • Small fluid-filled blisters, which may break
  • Headache, fever and fatigue if sunburn covers a large area

Any part of your body, including your earlobes, scalp and lips, can burn. Your eyes, which are extremely sensitive to the sun's ultraviolet light, can also burn. Sunburned eyes may feel painful or gritty.

Signs and symptoms of sunburn usually appear within a few hours after sun exposure. But it may take a day or more to know the full extent and severity of sunburn.

Within a few days, your body starts to heal itself by "peeling" the top layer of damaged skin. After peeling, your skin may temporarily have an irregular color and pattern. Depending on the severity, it may take several days or more for the sunburn to heal.

Causes

Sunburns are caused by exposure to too much ultraviolet (UV) light. UV radiation is a wavelength of sunlight in a range too short for the human eye to see. UV light is divided into three wavelength bands — ultraviolet A (UVA), ultraviolet B (UVB) and ultraviolet C (UVC). Only UVA and UVB rays reach the earth. Commercial tanning lamps and tanning beds also produce UV light and can cause sunburn.

When you're exposed to UV light, your skin accelerates its production of melanin. Melanin is the dark pigment in the epidermis that gives your skin its normal color. The extra melanin — produced to protect the skin's deeper layers — creates the darker color of a "tan." A suntan is actually your body's way of blocking the UV rays to prevent sunburn and other skin damage. But the protection only goes so far. The amount of melanin a person produces is determined genetically, and many people simply can't produce enough melanin to protect the skin well. Eventually, UV light causes the skin to burn, bringing pain, redness and swelling.

You can get sunburn on hazy or cloudy days. As much as 90 percent of UV rays pass through clouds. UV rays can also reflect off snow, ice, sand, water and other reflective surfaces, burning your skin as severely as direct sunlight.

Risk factors

People with fair skin are more likely to sunburn than are people with dark skin. That's because people with darker skin have more melanin, which offers some protection from sunburn but not from UV-induced skin damage.

Skin color is determined by the number, distribution and type of pigment-producing cells (melanocytes) in the skin. Dermatologists refer to the degrees of pigmentation in skin as "skin types." Skin types range from very little pigment (type 1) to very darkly pigmented (type 6). How easily you burn depends on your skin type and how light or dark your skin is.

Classification of skin types

       Skin type        Skin color                                Reaction to sun exposure

  • Type 1        Pale white skin                        Always burns, never tans
  • Type 2        White skin                               Burns easily, tans minimally
  • Type 3        White skin                               Burns minimally, tans slowly
  • Type 4         Light brown or olive skin       Burns minimally, tans easily
  • Type 5         Brown skin                             Rarely burns, tans easily and darkly
  • Type 6         Dark brown or black skin       Rarely burns, always tans, deeply pigmented

Regardless of your skin type, the sun's energy penetrates deeply into the skin and damages DNA of skin cells. This damage may ultimately lead to skin cancer, including melanoma. Even people with type 5 or 6 skin can develop skin cancer, often on the palms, fingers or other more lightly pigmented areas of their bodies.

In addition to skin type, living in a sunny or high-altitude climate increases your risk of sunburn. People who live in sunny, warm climates are exposed to more sunlight than are people who live in colder climates. In addition, living at higher elevations, where the sunlight is strongest, exposes you to more radiation and increases your chances of sunburn and skin damage.

Complications

Intense sun exposure that results in sunburn increases your risk of certain complications and related skin diseases. These include infection, premature aging of your skin and skin cancer.

Infection

Ruptured blisters make you more susceptible to bacterial infection. See your doctor if you notice signs or symptoms of infection, which include pain, redness, swelling or oozing.

Photoaging

Sun exposure and repeated sunburns accelerate the aging process of skin, making you appear older than you are. Skin changes caused by the sun are called photoaging. The results of photoaging include:

  • Weakening of connective tissues, which reduces the skin's strength and elasticity
  • Thinner, more translucent-looking skin
  • Deep wrinkles
  • Dry, rough skin
  • Fine red veins on your cheeks, nose and ears
  • Freckles, mostly on your face and shoulders
  • Large brown lesions (macules) on your face, back of hands, arms, chest and upper back (solar lentigines, or liver spots)
  • White macules on the lower legs and arms

Actinic keratoses

Also known as solar keratoses, actinic keratoses appear as rough, scaly areas in sun-exposed areas. They vary in color from whitish, pink or flesh-colored to brown-to-dark-brown patches. They're most commonly found on the face, ears, lower arms and backs of the hands of fair-skinned people whose skin has been damaged by the sun. Actinic keratoses are considered precancerous, as many evolve into skin cancer.

Skin cancer

Sun exposure that's intense enough to cause sunburn can also damage the DNA of skin cells. This damage sometimes leads to skin cancer. Skin cancer develops mainly on areas of skin exposed most to sunlight, including your scalp, face, lips, ears, neck, chest, arms and hands, and on the legs in women.

Some types of skin cancer appear as a small growth or as a sore that bleeds, crusts over, heals and then reopens. In the case of melanoma, an existing mole may change or a new, suspicious-looking mole may develop. Other types of melanoma develop in areas of long-term sun exposure and start as dark flat spots that slowly darken and enlarge, known as lentigo maligna.

See your doctor if you notice a new skin growth, a bothersome change in your skin, a change in the appearance or texture of a mole, or a sore that doesn't heal.

References

 

Eye damage

The sun can also burn your eyes. UV light damages the retina, a thin layer of tissue that lines the back inner wall of your eyeball. Burning your eyes can also damage the lens, a clear structure inside your eye that changes shape to help focus objects. This can lead to progressive clouding of the lens (cataracts).

Diagnosis

Your doctor is likely to conduct a thorough physical exam and to ask questions about your symptoms, UV exposure and sunburn history.

If you experience sunburns or skin reactions after relatively minor exposures to sunlight, your doctor may recommend phototesting. During phototesting, small areas of your skin are exposed to measured amounts of UVA and UVB light to try to reproduce the problem. If your skin reacts to the UV radiation, you're considered sensitive to sunlight (photosensitive).

References

http://www.medicinenet.com/sunburn_and_sun_poisoning/article.htm

http://www.mayoclinic.org/diseases-conditions/sunburn/basics/definition/con-20031065

http://www.emedicinehealth.com/sunburn/article_em.htm

http://www.nhs.uk/Conditions/Sunburn/Pages/Introduction.aspx