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Skin - abnormally dark or light |
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| Definition: | Skin that has turned darker or lighter than normal. See also skin color, patchy.
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| Alternative Names: | Hyperpigmentation; Hypopigmentation
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| Considerations: | Normal skin contains cells called melanocytes that produce the brown skin-coloring pigment melanin. There are several conditions in which melanocytes are either abnormal or abnormally distributed. Most skin conditions that cause discoloration are harmless.
A pale area of the skin is the result of fewer or less active melanocytes than usual, whereas a darker area (or area that tans more easily) indicates more numerous or more active melanocytes.
Sometimes mistaken for a suntan, bronzing of the skin often develops gradually starting at pressure points such as the elbows, knuckles, and knees and spreading from there. It is also seen in the creases of 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 intensity often a function of the underlying cause.
There are several types of benign hyperpigmentation that occur normally; however, any persistent hyperpigmentation that has not been medically explained should be seen by a dermatologist.
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| Common Causes: | - exposure to the sun
- medications
- endocrine diseases such as Addison's syndrome
- vitiligo
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Review Date: 11/11/2001
Reviewed By: Michael Lehrer, M.D., Department of Dermatology, University of Pennsylvania Medical Center, Philadelphia, PA. Review provided by VeriMed Healthcare Network.
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The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2003 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
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