The Best Tan is NO Tan

Human skin becomes damaged with a person's first exposure to sunlight as a baby and grows more damaged with each subsequent exposure, says Deborah Coody, M.S., R.N., C.P.N.P., a former cancer prevention specialist who now staffs the Health Services Clinic at The University of Texas-Houston Medical School.

There are three main types of skin cancer (the first two account for 90 percent of skin cancers):

• Basal cell carcinoma, which rarely metastasizes to vital organs but can destroy surrounding tissue, sometimes leading to the loss of an eye, ear or nose;
  
  
• Squamous cell carcinoma, a malignant tumor of the epidermis (the top layer of skin) which can invade the lower layer of skin and invade the lymph nodes, as well;
  
  
• Malignant melanoma is originally confined to the epidermis and then invades the lower layer and other organs.

Excessive sun exposure is the cause of at least 90 percent of all skin cancers, she says. However, if precautions are started early in life, almost all skin cancers can be prevented.

A number of environmental factors affect how much ultraviolet light reaches a person's skin:

• The thickness of ozone layer in the stratosphere
  
  
• Geographic latitude - the closer a person lives to the equator, the closer and more intense the sun's rays;
  
  
• For every 1,000 feet above sea level, radiation increases 4-5 percent;
  
  
• Exposure in tanning booths and salons;
  
  
• Skin type (there are six types, determined by a person's reaction to noonday sun in June following an exposure of 20-30 minutes at sea level) is also a factor.
  
  
• People with type I (the least resistant to UV rays) are very fair, often have freckles, light-colored eyes, and blond or reddish hair, tan poorly, burn easily and severely and then peel.
  
  
• Those with type II skin are fair with blue, green, gray or brown eyes and blond, red, or brown hair. They tan minimally or lightly, usually get a painful burn easily.
  
  
• The unexposed skin of type III people is white and they usually have brown hair and eyes, tanning gradually and burning moderately.
  
  
• Type IV-unexposed skin is white or light brown, dark hair and eyes (ethnic backgrounds from the Mediterranean, Asia and people of Hispanic descent). They burn minimally and tan well with first exposure.
  
  
• Type V-unexposed skin is brown (American Indian, East Indian, Hispanic backgrounds). They tan easily and profusely, rarely burn.
  
  
• Type VI-unexposed skin is black (African and American blacks, Australian and South Indian Aborigines). Their skin is deeply pigmented and it never burns.

Since the sun's UV rays are strongest between 10 a.m. and 4 p.m., exposure should be limited or avoided at these times. However, if you have to be outdoors, the American Cancer Society recommends following these preventative steps:

• Cover as much skin as possible with a hat that shades the face, neck and ears.
  
  
• Wear a long-sleeved shirt and long pants.
  
  
• Use a sunscreen of 15 SPF or higher (check with a pediatric specialist about the appropriate sunscreen strength to apply to infants or young children).

Early detection is critical for successful treatment. Practice skin self-exam regularly and have any suspicious lesions evaluated promptly by a physician. Use the ABCD rule to assess any skin growth or change for the possibility of skin cancer:

• A-Asymmetry, one half of the mole does not match the other half
  
  
• B-Border irregularity, the edges are ragged, notched or blurred
  
  
• C-Color, the pigmentation is not uniform with variable degrees of tan, brown or black
  
  
• D-Diameter greater than 6 millimeters, any sudden or progressive increase in size is of particular concern.

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©2006 Texas Medical Center

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