Normal skin contains special cells called melanocytes that produce the brown skin coloring pigment melanin. There are several conditions in which melanocytes are either abnormal or abnormally distributed. Sometimes they are fewer in number or less active than usual; this results in a pale area of skin that does not tan from the sun. Alternatively, the melanocytes may be more numerous or more active than usual. This results in a darker area of skin that tans very readily.Albinism: This is a rare inherited condition. The melanocytes are unable to make melanin, so an albino is very pale skinned and has white hair and pink or pale blue eyes. Albinos are advised to wear dark glasses and to avoid sunlight, because sun hurts their eyes and burns their skin easily.
Abnormal suntan: Certain diseases, and some drugs can provoke a “suntan” without exposure to sun. If this happens to you, see your physician.
Vitiligo: In vitiligo, pale irregular patches of skin appear, often symmetrically placed on either side of the body. The patches may grow, shrink, or stay the same size.
Pityriasis or tinea versicolor: This uncommon fungal infection causes patches of paler or darker skin to develop on the trunk. In addition, the affected skin may flake. Chloasma: Hormonal changes during pregnancy or while taking oral contraceptives cause some women to develop patches of darker skin on the face, particularly over the cheeks. The condition disappears after childbirth or when the pill is stopped.
Moles: These are small dark areas of skin composed of dense collections of elaborates. Some moles are hairy. Very occasionally, one may become malignant. If you have a mole that changes in size or shape, you should see your physician.
Seborrheic warts: These are not true warts , but round or oval patches of dark skin 1 to 3 cm (up to about 1 in) across. They are common and often develop after middleÂage. They have a crusty, greasy surface.
What should be done?
Most of these conditions are harmless, but if you are concerned, especially about a mole. consult your physician.
Self-help: You can find a number of nonÂprescription depigmenting creams available for lightening skin, but follow the instructions carefully and do not use one for more than a few weeks at a time. The darker your skin is. the more care you should take in using these preparations. Covering the discoloration with ordinary cosmetics may help.
Professional help: There are specific treatments available for some of these conditions. Vitiligo may be improved by ultraviolet lamp treatment combined with drug therapy. Pityriasis can be cured by an antifungal ointment. Moles may be cut out. Special cosmetics can cover various blemishes.