Age spots, also known as liver spots or solar lentigines, are flat, brown, gray, or black spots that typically appear on sun-exposed areas of the skin. They are most common in adults over 50, but younger people can also get them if they spend a lot of time in the sun. Age spots are caused by an excess production of melanin, the pigment that gives skin its color. Factors such as prolonged sun exposure, aging, and genetic predisposition can contribute to their development.