Melanin determines skin and hair color. It also is present in the skin in varying degrees, depending on how often a population has been exposed to the sun in the past. Melanin can be found in the pupils or irises of the eyes and areas of the brain.
There are different types of melanin, including eumelanin, pheomelanin and neuromelanin. Eumelanin is found in the hair, skin and dark areas around the nipples. It also provides black and brown pigment to the hair, skin and eyes, particularly among the black populations. Hair is blonde when eumelanin is only present in small amounts.
Pheomelanin is found in the hair and skin as well. It provides pink and red colors and is the main pigment in red-haired individuals. Pheomelanin is not as protective against cancer caused by ultraviolet radiation as eumelanin.
Neuromelanin is found in different areas of the brain. Losing this melanin can cause many neurological disorders.
Skin pigmentation disorders affect skin color. The cells that make melanin can become damaged or unhealthy, which can affect melanin production. Too much melanin causes the skin to get darker; pregnancy, Addison’s disease and sun exposure can all cause this to happen. Too little melanin causes the skin to get lighter, which can be caused by vitiligo. Albinism is a genetic condition in which a person may have no skin color, lighter than normal skin color or patchy skin color. Infections, blisters or burns can also cause lighter skin.