Freckles are flat, rounded spots on the skin that typically range in size from that of a pinhead to about 0.25 inches (about 0.6 cm) in diameter. Most freckles are consistent in color, but they can appear differently according to a person's skin tone. Freckles are usually slightly darker than the surrounding skin and can be yellow, light brown, red, dark brown or black in color. Back freckles are caused when the skin on the back contains excessive amounts of melanin, which the skin produces after exposure to the sun.
Melanin is a skin pigment that determines a person's skin tone. The pigment is produced by melanocytes cells, which also determine a person's hair and eye color. After exposure to the sun's ultraviolet rays, the outer layer of the skin thickens, and the melanocytes cells rapidly produce melanin. When the body distributes melanin unevenly in the skin, a freckle essentially appears. Although most freckles are circular, some can be uneven and can exceed more than 0.5 inches (1.27 cm) in diameter.
Spots on the body that commonly produce freckles are those that are most frequently exposed to sunlight, including the back, shoulders, nose and arms. Individuals who acquire back freckles generally have fair skin and have had too much exposure to the sun's ultraviolet rays. Although genetics play a large part in the amount of freckles that a person possesses, sunlight and ultraviolet rays can increase the amount of melanin that the body produces. Back freckles are nothing more than abnormally heavy deposits of melanin and generally do not represent a health risk.
Heredity plays a large part in the way a person reacts to sun exposure. Individuals who have light skin generally produce more melanin to protect the skin from exposure. On the other hand, individuals who have dark complexions usually are less sensitive to the sun's ultraviolet rays because of excessive amounts of melanin already in the skin, and they do not produce freckles as frequently as people who have fair complexions. Individuals who have evident back freckles typically are light skinned, have red or blond hair and have light-colored eyes.
It is important for individuals who have excessive amounts of back freckles to take precautions to protect from future damage to the skin. Avoiding the sun between peak hours and wearing sun-protective clothing can prevent the production of additional freckles on the back. For individuals who must expose their backs to the sun, wearing sunscreen can protect the skin from unnecessary exposure and diminish the chances of producing additional back freckles.