Melasma
(Chloasma)
(June 1999)
Melasma (also known as chloasma) is a skin condition in which brown patches occur primarily on the cheekbones, forehead and upper lip. It also may develop on the nose chin, lower cheeks and sides of the neck. The dark patches usually have distinct edges. Melasma is seen most frequently in young women taking birth control pills and also occurs commonly during pregnancy. It may develop in association with menopause, hormonal imbalance and ovarian disorders. Melasma may also be triggered by a medication called Dilantin (phenytoin). In many cases, it occurs without any of these predisposing factors and is occasionally seen in men. The keys to melasma prevention and treatment are sun avoidance/protection and skin lightening products.
The tendency to develop melasma is genetically predetermined. Most of the genetic factors that contribute to this tendency are not yet understood, but it is clear that persons who have inherited baseline skin color in the very light olive to very dark olive range are particularly susceptible. Melasma has been referred to as the mask of pregnancy because it often develops during pregnancy. Because of melasma’s relation to pregnancy and oral contraceptives, it is thought that estrogen contributes to its development in predisposed persons. Estrogen is not essential to the development of melasma, however, as men may also be affected. A factor that does seem to be essential to the development of melasma is sunlight. Both ultraviolet A (UVA) and ultraviolet B (UVB) are believed to contribute to the formation of melasma in predisposed persons.
The pigmentation of melasma may be
deposited in one or more layers of the skin. The pigment may be
confined to the surface layer of skin, the epidermis. Alternatively,
it may be present solely in the inner layer of skin, the dermis.
Generally, however, it is present to a greater or lesser degree in both
outer layers of skin. The presence of pigment both within the skin’s
surface layer as well as deeper within the skin has important implications
for melasma treatment.
Melasma develops due to a combination of genetic, hormonal and sun related factors. In order to prevent melasma, this combination has to be altered. It is impossible to change the genetic tendency towards melasma and often not practical to alter hormonal influences. Thus the mainstay of melasma prevention is complete sun protection including regular use of broad-spectrum sunscreens and sun protective hats and clothing as well as avoidance of sun within practical limits. The treatment of existing melasma is based upon this idea of total sun protection as well as the use of products designed to decrease pigment within the surface skin layer.
Dermatologists typically recommend sunscreen every morning, hydroquinone containing skin bleaches at bedtime or twice daily and vitamin A derivatives nightly as tolerated for persons with melasma. This regimen generally provides visible results within a couple months and optimal results within six months. All sunscreens are over the counter and milder skin bleaches and vitamin A products are also available over the counter. More potent and potentially irritating bleaches and vitamin A derivatives are available by prescription. Dermatologists also may recommend on a case by case basis chemical peeling with either glycolic or tri-chloro-acetic (TCA) acid to speed improvement of melasma. Microdermabrasion has also been found to be helpful in the treatment of melasma especially when used in concert with topical products.
Regardless of the methods used to treat melasma, results vary greatly. Much of this variation is because of differences in where the melasma related pigment is located within the skin in different people. Surface pigment is relatively easily removed by standard treatments but deeper pigment does not respond to surface treatment. Deeper pigment does, however, tend to slowly fade away over months to years if there is complete and consistent sun protection. People with primarily surface pigment can expect to see more rapid and dramatic results from treatment than those with primarily deeper pigment. One day of unprotected sun exposure in a person prone to melasma can undo months of treatment, especially in those with a tendency towards deeper pigment.
Melasma is a challenge to successfully treat and requires great discipline with regards to continuous sun protection. Fortunately, most people can obtain satisfying results with a combination of sunscreen/avoidance and appropriate topical
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