Brenda Spriggs, MD, MPH, MBA
Both melanoma and age spots can cause brown lesions on the skin. It is very important to differentiate these two skin conditions. While age spots can be a cosmetic nuisance, they are harmless. Melanoma, however, can be deadly. In fact, melanoma is the most dangerous form of skin cancer. Although melanoma and age spots share some common features, there are some distinguishing characteristics.
A 2016 report from the American Cancer Society reports that melanoma accounts for only 1 percent of all skin cancers in the U.S. but is responsible for the overwhelming majority of skin cancer deaths. Melanoma occurs when the pigment cells, or melanocytes, in the skin become cancerous. Skin lesions due to melanoma may be raised or flat and are often dark brown or black. However, color variation within the lesion is very common with melanoma. This can include variable shades of brown, black, red, blue and even white. Other common characteristics of melanoma include:
-- asymmetry, meaning one half doesn't mirror the other half
-- irregular or poorly defined borders
-- size larger than 6 mm, or about the size of a pencil eraser
-- change in shape, color and/or size over time
Melanoma can develop at any age in adults, although the risk increases with advancing age. It occurs rarely in young children, but can develop in adolescents. Melanomas may arise in a preexisting mole or develop anew. Unlike age spots, melanomas often itch, bleed easily or are tender.
Age spots -- also known as liver spots or solar lentigines -- are linked to aging and exposure to ultraviolet (UV) radiation from the sun or tanning bed use. These noncancerous, pigmented patches form on UV-exposed areas of the skin, such as the face, upper back, shoulders, backs of the hands and forearms. Age spots develop when skin damage caused by UV radiation caused increased proliferation of melanocytes and other cells in the superficial layer of the skin. A brownish pigment called melanin produced by the melanocytes accumulates in the upper layer of the skin leading to age spots. Age spots typically make their initial appearance in middle-aged adults, and tend to gradually increase in size and number over the years as a person ages.
Like freckles, solar lentigines are characteristically flat and multiple spots tend to occur together in an affected area. Unlike freckles, however, age spots do not fade. They are most commonly light brown, but can be dark brown or black. In contrast to melanoma skin lesions, age spots are characteristically uniform in color. They can be round, oval or irregular in shape. However, they have distinct borders and remain relatively stable in appearance over time, though they may enlarge very slowly over a period of years. Unlike melanoma skin lesions, age spots do not cause any symptoms.
People with fair skin and those who have a history of heavy sun exposure are at increased risk for age spots, melanoma and other forms of skin cancer. To prevent sun-related skin damage, the American Academy of Dermatology advises daily use of sunscreen with an SPF of 30 or higher, even on cloudy days. Be sure to choose a sunscreen that provides specific protection for both UVA and UVB, two types of damaging ultraviolet radiation from the sun. Wearing protective clothing and minimizing time outside when the sun is most powerful -- between 10 a.m. and 2 p.m., is recommended as well.
Age spots do not require treatment, although it's possible to treat them cosmetically with fading creams or laser treatments. If melanoma is diagnosed before it has spread to other organs, it is highly curable. Melanoma must be surgically removed. Depending on the size of the lesion, melanoma can sometimes be removed in a dermatologist's office. If melanoma has invaded deep into the skin or spread to other organs, chemotherapy or radiation therapy may be necessary.
Warnings and Precautions
Age spots are not cancerous, but they do indicate UV skin damage, a major risk factor for skin cancer. As such, people with age spots should keep an eye out for other potentially cancerous skin growths. If you have multiple moles or age spots, it's a good idea to have an annual skin exam. If you notice a mole or spot on your skin that looks unusual or has changed in appearance, see your doctor as soon as possible. Early diagnosis and treatment can be life-saving.
Reviewed by: Tina M. St. John, M.D.