Pigmentation is a term that describes an object's coloring. When used in regard to people, it typically refers to the color of an individual's skin. Your particular skin pigmentation results from the combined effects of your genetic heritage and your everyday environment. In some cases, abnormalities in your pigmentation may indicate the presence of an underlying skin disorder.
Melanin
The primary factor in determining your skin's pigmentation is a substance called melanin, which your skin produces in specialized cells called melanocytes. Individuals with darker skin produce more melanin than individuals with lighter skin. In addition to coloring your skin, melanin helps provide your body with protection from harmful rays contained within sunlight. The relative presence of melanin also helps determine the color of your hair and the irises in your eyes.
Additional Pigmentation Factors
In addition to melanin, your skin's pigmentation is determined by several other factors. Oxygen-rich hemoglobin in your blood cells produces a red pigmentation, while oxygen-depleted hemoglobin produces a blue pigmentation. You also derive a degree of yellow pigmentation from foods in your diet that contain substances called carotenoids. In addition to these factors and the genetic limitations of basic melanin production, your skin's pigmentation depends on the amount of sun exposure you receive and the ways in which your skin reacts to sunlight's ultraviolet radiation.
Birthmarks
You can be born with a variety of skin pigmentation disorders called birthmarks. Common types of birthmarks include light-brown café-au-lait spots, bluish Mongolian spots, red macular stains and congenital moles, which range in color from pale to dark brown. You may also have birthmarks, such as reddish hemangiomas and port wine stains, that result from abnormalities in the development or composition of the blood vessels beneath your skin. In some cases, these abnormalities can pose significant risks to your health, according to the Cleveland Clinic. Port wine stains on your skin can also indicate the presence of certain rare medical disorders.
Other Skin Disorders
A number of other disorders can also trigger changes in your skin pigmentation. In the inherited disorder called albinism, lack of melanin production triggers a distinct lack of pigmentation in your skin, hair and eyes. In individuals with an autoimmune disorder called vitiligo, elements of the immune system mistakenly attack melanin-producing melanocytes, leading to the formation of smooth, white patches of skin. Individuals with the skin disorder called melasma typically develop brown or tan patches of skin on their noses, foreheads, cheeks, chins or upper lips.
Considerations
Unusual increases in your melanin output can result from either an increase in the amount of melanocytes in your skin or from increased production in your existing melanocytes, the New Zealand Dermatological Society notes. Additional potential factors in the development of unusually dark skin pigmentation include pregnancy and the presence of an adrenal gland disorder called Addison's disease. Additional factors that can trigger unusual skin lightening include the effects of burns, blisters or infectious diseases.
