Liver spots--also called age spots or solar lentigines--are brown, irregular patches on the skin. They are most common on sun-exposed areas, including the shoulders, back, arms, forehead, cheeks, nose and the backs of the hands. Age spots range from roughly the size of the head of a pin up to 1 inch. They are painless, do not itch and are not elevated above the skin surface. Despite their name, liver spots have nothing to do with the liver. They are the result of increased skin pigmentation typically caused by exposure to the sun or other ultraviolet light.
Increased Melanocytes and Melanin
The skin contains cells called melanocytes, which produce the substance melanin. Melanin is the brown pigment that gives the skin its color. People with darker skin have more melanin than those with lighter skin. Age spots appear because of an increased number of melanocytes and their increased production of melanin in the affected areas of the skin. The expansion of melanocyte populations and the accumulation of melanin occur over many years. Age spots typically begin to appear around age 40.
Sun Exposure
Over time, sun exposure damages the melanocytes. This damage causes the melanocytes to increase melanin production, eventually leading to age spots. In a 2009 study published in the journal "Experimental Dermatology," Dr. N. Chen and colleagues reported exposure to ultraviolet B light (UVB) stimulates secretion of a chemical that increases melanin production in experimental models. Researchers continue to study the exact mechanisms by which UV exposure leads to age spots and other sun-induced skin damage.
Sun Lamps and Tanning Beds
Commercial sun lamps and tanning beds emit UV light, thereby exposing the skin to the same potentially damaging radiation as is present in sunlight. Since sun exposure is known to cause age spots, regular use of sun lamps and tanning beds have the potential to cause the same process.
Advancing Age
Advancing age itself is a contributing cause to the development of liver spots. As the skin ages, it produces more pigment, which contributes to age spots. The contributing role of time to the development of age spots is borne out by the fact that more lesions appear as a person ages. Although age spots have no adverse effects on health, they may cause emotional distress because of their effects on appearance. A 2009 review article in the journal "American Family Physician" reported that laser therapy, local freezing, chemical peels and topical medications can effectively remove or fade age spots.
References
- Mayo Clinic: Age Spots (Liver Spots), Causes
- University of Maryland Medical Center: Liver Spots
- American Osteopathic College of Dermatology: Lentigines
- American Family Physician: Common Pigmentation Disorders
- "Experimental Dermatology"; The Role of Keratinocyte Growth Factor in Melanogenesis: A Possible Mechanism for the Initiation of Solar Lentigines; N. Chen, et al; September 2009
