Sun exposure affects the skin throughout a person’s lifetime. The sun emits an invisible form of radiation called ultraviolet (UV) radiation, which can damage the skin. There are three types of UV rays: ultraviolet A (UVA), ultraviolet B (UVB) and ultraviolet C (UVC). UVA rays are the most abundant rays at the earth’s surface, whereas UVB rays are the most harmful. UVC rays are especially damaging to the skin. However, they are completely absorbed by the ozone layer (the protective layer in the earth’s atmosphere) and never reach the surface of the earth.

UV radiation interacts with the skin and causes it to produce melanin, the pigment that gives skin its color. When the darker colored melanin reaches the top layer of the skin, it results in a “suntan.” Eventually, the UV rays will cause the skin to burn. Sunburn is often accompanied by redness, swelling and pain in the affected region(s).

Some people tan very easily and rarely burn, whereas others burn very easily and rarely develop a tan. A variety of factors determine whether an individual tans or burns after sun exposure, including skin type, amount of recent sun exposure and time of year.

No one is immune from the risk of sun damage. However some individuals are more likely to sustain damage than others, including people with fair skin and light-colored eyes, individuals with many moles, birthmarks or freckles and those with a family history of skin cancer.

Excessive sun exposure over time can be harmful to the skin because the sun emits an invisible form of radiation called ultraviolet (UV) radiation. The UV rays present in sunlight can penetrate the skin and alter the structure of its cells. The ultraviolet radiation received from sun exposure is also present in the light exposure received from sun lamps and tanning beds.

The three types of UV radiation include:

• Ultraviolet A (UVA). The most abundant source of solar radiation at the surface of the earth, UVA rays can penetrate beyond the surface of the skin (epidermis) to the middle layer of skin (dermis).
  
  

  

• Ultraviolet B (UVB). These rays are less plentiful at the earth’s surface than UVA rays because the ozone layer (the protective layer in the earth’s atmosphere) absorbs a large portion of UVB rays. UVB rays penetrate only the epidermal skin layer. However, they are the most harmful form of ultraviolet radiation.
  
  
• Ultraviolet C (UVC). Although these solar rays would be especially harmful to the skin, they are completely absorbed by the ozone layer and never reach the earth’s surface.

UV rays are not only present on bright, sunny days. They are emitted on cloudy and hazy days as well. In addition, UV rays reflect off surfaces such as water, sand, concrete and snow.

When UV rays penetrate the epidermis, their energy interacts with cells called melanocytes to produce a colored substance called melanin. Melanin produces the darker coloring of skin. The new melanin eventually travels toward the surface of the skin to protect it from UV rays and the skin becomes darker, or tans. Some physicians believe that tanning is the skin’s response to injury because it occurs after UV rays from the sun have damaged and killed some skin cells.

Eventually, the UV rays will cause the skin to burn. Sunburn is often accompanied by redness, swelling and pain in the affected region(s). If the sunburn is particularly severe, the damaged skin may peel away and be replaced by new skin cells. Although sunburn symptoms diminish over time, the resulting skin damage will remain. Severe sunburn can even alter some of the genetic structure of skin cells. This may lead them to create new cells that are damaged, which may eventually lead to skin cancer.

Some individuals tan very easily and rarely burn, whereas others burn with minimal sun exposure and rarely tan. Numerous factors determine whether a person tans or burns after sun exposure. These include skin type, amount of recent sun exposure, time of year and sun strength. The American Academy of Dermatology (AAD) and the U. S. Food and Drug Administration (FDA) use a six-level scale to classify an individual’s susceptibility to sunburn:

Brief, unprotected sun exposure (10 to 15 minutes on the face, hands, arms or back twice a week) can be beneficial because it helps the body produce vitamin D. This nutrient is essential for the maintenance of healthy bones and teeth. However, the AAD urges people to practice sun protection and seek vitamin D through diet instead. Vitamin D can be found in many foods, including fortified milk and breakfast cereals, eggs, mushrooms, herring and salmon.

Although everyone is at risk for sun damage, the following factors increase an individual’s likelihood of sustaining damage, particularly skin cancer:

• Fair skin
• Light-colored eyes
• Light-colored hair
• Lack of sunscreen protection
• Having had one or more serious sunburns
• Many moles, birthmarks or freckles
• Playing or working outdoors
• Frequent sun exposure during childhood
• Personal or family history of skin cancer
• Frequent tanning or use of sun lamps or tanning beds
• Living in a tropical or subtropical climate
• Living at high altitudes

Taking certain medications, including specific forms of antibiotics, nonsteroidal anti-inflammatory drugs, tricyclic antidepressants, diuretics, sulfonylureas and immunosuppressants, can also increase the risk of sun damage by increasing photosensitivity (sun sensitivity) and burning.

It is recommended that individuals have regular physical examinations by a dermatologist to detect or determine the risk of skin cancer and other damage.

The effects of sun exposure are cumulative, meaning that damage from the sun accumulates over time. Sun lamps and tanning beds can also produce similar skin damage. Too much sun over time can result in the following:

• Sunburn. Excessive acute sun exposure may result in sunburn, which is characterized by redness of the skin that may be accompanied by dryness, swelling, pain or tenderness, blistering, nausea and/or fever.
  
  
• Premature aging. Excessive sun exposure over time can lead to skin changes known as photoaging. Individuals who sunbathe regularly often show signs of photoaging prior to 30 years of age, whereas individuals with less sun exposure typically exhibit changes at 40 years of age or older. These photoaging changes may include:
  
  
  • Weakening of the skin’s connective tissues (solar elastosis), which results in reduced strength and elasticity
    
    
  • Thinning and increased transparency of the skin
    
    
  • Deep wrinkles
    
    
  • Rough, dry skin
    
    
  • Uneven pigmentation
    
    
  • Fine, red veins on the nose, cheeks and ears
    
    
  • Freckles (mainly on the face)
    
    
  • Macules or solar lentigines (also called age or liver spots) on the upper back, chest, arms, back of hands and face
    
    
  • Dark brown lesions on the lips (labial lentigos)
    
    
• Purpura. Excessive sun exposure can cause a person to bruise more easily.
  
  
• Comedones. Exposure to the sun may lead to the formation of blackheads and whiteheads in sun damaged areas.
  
  
• Benign skin tumors. Excessive sun exposure can also result in the formation of several types of skin lesions. Seborrheic keratoses are tan, brown or black lesions that vary in size and have a waxy appearance and are noncancerous.  Actinic, or solar keratoses, are patches that range from brown to dark pink in color and appear rough and scaly. Actinic keratoses are often considered precancerous.
  
  
• Skin cancer. According to the U.S. Centers for Disease Control and Prevention (CDC), excessive sun exposure (including severe sunburns) over time appears to be the most significant environmental factor in the development of skin cancer. It affects one out of every five Americans, according to the Environmental Protection Agency (EPA). This disease typically affects the areas that receive the most sun exposure, including the face, ears, neck, forearms and hands. There are two main types of skin cancer:
  
  
• • Non-melanoma skin cancer. Far more common and much less dangerous than melanoma skin cancer. The two most common forms include:
    
    
  • • Basal cell carcinoma. A tumor that typically appears as a small, fleshy, shiny nodule on an exposed area of the body. It grows slowly and rarely spreads (metastasizes) to other regions of the body. However, this type of tumor can severely damage surrounding skin.
      
      
    • Squamous cell carcinoma. A tumor that usually appears on the ears, face, mouth or lips as a scaly, red patch or nodule. Left untreated, this type of tumor can metastasize to other regions of the body and may be fatal.
      
      
  • Melanoma skin cancer. A tumor that normally appears suddenly as a dark patch or mole with irregular edges. Sometimes a melanoma is multicolored with shades of white, blue or red. Left untreated, it can metastasize to other regions of the body and may be fatal. According to the American Academy of Dermatology (AAD), melanoma is the most common type of cancer among women between the ages of 25 and 29. Approximately every 68 minutes, one person in the United States dies from melanoma.
    

Individuals who suspect they have skin cancer should immediately contact a dermatologist. All types of skin cancer are curable if detected early.

• Sun sensitivity (photosensitivity). For some individuals, exposure to the sun may result in an allergic reaction. Signs of sun allergy may include bumps on the skin, hives, blisters or blotchy, red areas. Certain cosmetics, perfumes and medications may also make individuals sensitive to sun exposure.
  
  
• Immunological problems. Regardless of an individual’s susceptibility to sunburns, sun exposure can suppress the immune system and increase an individual’s vulnerability to infection and cancers. Diseases that affect the immune system (e.g., herpes simplex virus, lupus) can become worse with exposure to sun.
  
  
• Eye damage. Excessive exposure to ultraviolet (UV) radiation may burn the cornea of the eye and increase the risk of developing a cataract (condition in which the lens of the eye becomes cloudy). It may also cause macular degeneration, the deterioration of part of the retina of the eye, which may result in blindness.

Although much of the damage sun causes to the skin is not reversible, there are treatments available to improve the skin’s appearance. Topical treatments are available to address mild to moderate sun damage. More severely damaged skin may require cosmetic surgery procedures, such as chemical peels, dermabrasion or facial skin rejuvenation. Lasers and photofacials can also be used to treat sun damage.

Protection from the sun’s ultraviolet (UV) rays is important year round, not merely during the summer months. The following steps may be taken to reduce the risk of damage from sun exposure:

• Limit sun exposure. The rays of the sun are the strongest, and thus cause the most damage, between the hours of 10:00 a.m. and 4:00 p.m. People should plan their outdoor activities for early morning or late afternoon. If it is not possible to avoid sun exposure during peak hours, individuals should attempt to seek shade under a tree, beach umbrella or tent, especially during the summer months and/or in regions with high altitudes. Individuals may also benefit from limiting use of sun lamps and tanning beds, which emit UV rays and can produce skin damage comparable to that caused by excessive sun exposure. Infants younger than 6 months should be kept out of all direct sunlight.
  
  
• Cover up. When spending time outdoors cannot be avoided, protective clothing such as a long-sleeved shirt and pants can help prevent sun damage. Many sun-protective garments have a label that lists the ultraviolet protection factor (UPF) value. The highest UPF value is 50+, which only allows 1/50^th of the sun’s radiation to penetrate the garment. Tightly woven clothing blocks out the sun and prevents damage more effectively than garments that are loosely woven. Darker colors may offer more protection than lighter shades. Wet clothing loses some of its protective ability.
  
  
• Wear a hat. Wide-brimmed hats protect the ears, neck, eyes, forehead, nose and scalp. A baseball cap or visor covers the scalp and forehead, but offers little or no protection for the ears and neck.
  
  
• Use sunscreen. Frequently apply sunscreen with a sun protection factor (SPF) of at least 15. If a person typically burns in 10 minutes, an SPF of 15 will protect them 15 times longer, or for 150 minutes. It is important to follow the directions on the sunscreen's label, including when to reapply, and to check the product’s expiration date. SPF ratings refer only to UVB protection. Individuals should be sure to choose a broad-spectrum sunscreen that includes protection against both UVA and UVB. Sunscreen should be applied 20 minutes before going outside and reapplied after swimming or sweating. Children should begin wearing sunscreen at 6 months of age.
  
  
• Wear UV-absorbent sunglasses. Sunglasses protect against cataracts and ocular melanoma. Even inexpensive sunglasses can be effective. Look for ones that block 99 to 100 percent of UVA and UVB radiation. Wrap-around or close-fitting sunglasses offer the best protection because they shade the sides of the eyes as well.
  
  
• Check the UV index. Developed by the Environmental Protection Agency (EPA) and National Weather Service, the UV index forecasts the expected strength of UV radiation on a given day and indicates the level of caution people should use when playing, exercising or working outdoors. Exposure levels are predicted on a scale of 0 to 11+, where 0 indicates minimal risk of overexposure and 11+ indicates maximum risk of overexposure. The UV index is calculated one day in advance and accounts for such factors as cloud coverage and local conditions that affect the quantity of UV radiation. Expected risk of overexposure is calculated for an individual with Type II skin. Therefore, adjustments may be necessary for people with other skin types.
  
  
• Check personal care products and medications. Some products, including cosmetics, perfumes and a number of prescription drugs, can increase a person’s photosensitivity, placing them at increased risk of sun damage. Patients can discuss the risks associated with medications and other products with their physician or pharmacist.
  
  
• Regular physical examinations. Routine examinations by a dermatologist qualified to diagnose skin conditions – including skin cancer – are recommended for individuals with all levels of sun exposure. In between clinical exams, monthly self-examinations are recommended.

Parents should begin teaching their children about sun safety at an early age. Regularly applying sunscreen to a child can help them develop good sun habits they will continue to use for the rest of their lives.

Preparing questions in advance can help patients to have more meaningful discussions with their physicians. Patients may wish to ask their doctors the following questions about sun exposure:

1. Is tanning safe for someone with my skin type?
   
   
2. How can I protect my skin from sun damage?
   
   
3. What SPF should my sunscreen contain?
   
   
4. Am I at risk for skin cancer?
   
   
5. Am I at risk for premature aging?
   
   
6. Do any of my current medications put me at increased risk for sun damage?
   
   
7. Can you show me how to perform self-examinations of the skin?
   
   
8. How often should I perform self-examinations of my skin?
   
   
9. Will staying out of the sun increase my risk of vitamin D deficiency? Should I take supplements or make changes to my diet?
   
   
10. Are there any steps I can take to reverse the damage I have already caused my skin?