Definition of Skin - abnormally dark or light:

Skin that has turned darker or lighter than normal is usually not a sign of a serious medical condition.

See also: Skin color, patchy

Considerations:

Normal skin contains cells called melanocytes. These cells produce melanin, the substance that gives skin its color.

Skin with too much melanin is called hyperpigmented skin.

Skin with too little melanin is called hypopigmented skin.

Pale skin areas are due to too little melanin or underactive melanocytes. Darker areas of skin (or an area that tans more easily) occurs when you have more melanin or overactive melanocytes.

Bronzing of the skin may sometimes be mistaken for a suntan. This skin discoloration often develops slowly, starting at the elbows, knuckles, and knees and spreading from there. Bronzing may also be seen on the soles of the feet and the palms of the hands. The bronze color can range from light to dark (in fair-skinned people) with the degree of darkness due to the underlying cause.

Common Causes:

Causes of hyperpigmentation include:

• History of skin inflammation (post-inflammatory hyperpigmentation)
• Use of certain medications (such as minocycline)
• Endocrine diseases such as Addison's disease
• Hemochromatosis (iron overload)
• Sun exposure

Causes of hypopigmentation include:

• History of skin inflammation
• Certain fungal infections (such as tinea versicolor)
• Pityriasis alba
• Vitiligo