Skin that has turned darker or lighter than normal. See also skin color, patchy.
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.
- exposure to the sun
- endocrine diseases such as Addison’s syndrome
Nonprescription depigmenting creams are available for lightening the skin. If used, follow instructions carefully and don’t use one for more than 3 weeks at a time. Darker skin requires greater care when using these preparations. Cosmetics may also help in covering a discoloration.
Avoid too much sun exposure (use sunscreens or blockers).
Hyperpigmentation may persist even after treatment, so emotional support is recommended.
Call your health care provider if
- a skin discoloration causes significant concern or lifestyle impairment.
- there is persistent, unexplained darkening or lightening of the skin.
- any hyperpigmented area (like a mole) changes shape, size, or color (this may be a sign of malignancy).
What to expect at your health care provider’s office
The medical history will be obtained and a physical examination performed.
Medical history questions documenting abnormally dark or light skin in detail may include:
- time pattern o When did the discoloration develop? o Did it develop suddenly? o Is it getting worse? How fast?
- quality o Describe the change. o Is the skin turning darker or lighter?
- location o Exactly where is the discoloration? o Has it spread to other parts of the body? In what pattern?
- aggravating factors o What medications are used? o Is there anyone else in your family that has had a similar problem? o Are you often in the sun or exposed to a sun lamp? o What is your diet like?
- other o What other symptoms are also present? o Are there any rashes or skin lesions?
The physical examination may include emphasis on evaluating the skin.
Diagnostic tests that may be performed include:
- adrenocorticotropin hormone stimulation test
- skin biopsy
- thyroid function studies
- examination of the area under a Wood’s lamp
Some skin conditions can be treated. Vitiligo may be treated using ultraviolet lamp treatment combined with drug therapy. Pityriasis versicolor is usually treated using anti-fungal ointment. Moles that have changed color are usually surgically removed and a biopsy is taken.
Some pigment changes spontaneously return to normal skin color (unless there is scarring of the skin).
by Janet G. Derge, M.D.