Skin Pigmentation

Sun Exposure and Pigmentation Conditions

It's common knowledge that too much sun exposure is not a good thing. No one wants to end up with leathery, snake-like skin. But that's only one side effect of letting UV rays attack your body.

The three most common forms of skin cancer can be traced to sun damage, and all three are on the rise. Basal cell carcinoma is the most common nonmelanoma skin cancer and the most treatable form, but if it's left untreated too long, it can cause damage to nearby tissue and bone. Basal cell is also the most likely skin cancer to recur. Squamous cell carcinoma is second most common form of nonmelanoma skin cancer, and it is completely curable when caught and treated. Melanoma, the most dangerous of the skin cancers, affects the melanocytes. It, too, is curable when caught early, but can be deadly when left untreated [source: Mayo Clinic].

Other skin pigmentation conditions are more cosmetic in nature. Age spots, also known as solar lentigos, can be traced directly to sun exposure. While they are not dangerous in themselves, age spots can indicate a risk of skin cancer. Rough, scaly, discolored patches of skin that don't go away may be actinic keratoses, or solar keratoses. As the name implies, they also arise from exposure to too much sun. Sometimes, these patches can evolve into squamous cell carcinoma.

Skin pigmentation may be an adaptation to a past migration, but in a way, humans must continue to adapt -- this time by making sure we take in only the appropriate amount of sunlight, regardless of our skin color.

For more information about sun exposure and your skin, read on to the following page.

Related HowStuffWorks Articles


  • American Academy of Dermatology. "Dermatologists Shed Light on Common Pigmentation Problems and Solutions in Skin of Color." (Accessed 8/10/09)
  • American Vitiligo Research Foundation. "Vitiligo Signs and Symptoms." (Accessed 7/30/09)
  • Cleveland Clinic. "Abnormal Skin Pigmentation." (Accessed 8/10/09)
  • Dreifus, Claudia. "A Conversation With Nina G. Jablonski: Always Revealing, Human Skin Is an Anthropologist's Map." New York Times. January 9, 2007. (Accessed 8/10/09)
  • Gadsby, Patricia. "The Inuit Paradox: How Can People Who Gorge on Fat and Rarely See a Vegetable Be Healthier Than We Are?" Discover. October 1, 2004. (Accessed 8/10/09)
  • Mayo Clinic. "Skin Cancer." (Accessed 8/10/09)
  • MedicineNet. "Definition of Melanin." (Accessed 8/9/09)
  • Mighall, Robert. "A History of Tanning." The Times. April 25, 2008. (Accessed 8/10/09)
  • National Geographic. "Skin: The Body's Protective Cover." (Accessed 8/10/09)
  • National Institutes of Health's Office of Dietary Supplements. "Dietary Supplement Fact Sheet: Vitamin D." (Accessed 8/10/09)
  • University of Maryland Medical Center. "Anatomy of the Skin" (Accessed 8/9/09)
  • USA Today. "Your Health: Skin Color Matters in the Vitamin D Debate." (Accessed 8/10/09)
  • Webster's Online Dictionary. "Melanin" (Accessed 8/10/09)
  • YourSkinDoctor. "Hyperpigmentation" (Accessed 8/9/09)