Etiology melasma until now has not been definitely known. According Supardiman (2007), factors that are considered causative role in the occurrence of melasma is patogenesis:
1. Ultraviolet rays.
Spectrum sun damage this cluster sulfhidril in the epidermis which is the enzyme tirosinase resistor with the binding of the enzyme Cu ion is. Ultraviolet rays cause the enzyme tirosinase not dihambat again, so that drive the process of melanogenesis.
Other mechanisms that cause sun exposure can cause melasma is the ultraviolet ray radiation can cause cell membrane lipid peroksidasi so that the generated free radicals stimulate melanosit to release melanin. Curtain especially to block the solar UV-B radiation (290-320 nm) is not satisfactory because there is a wavelength that is longer on the UV-A rays and visible radiation (320-700 nm) have the nature melanosit stimulated to produce melanin.
2. Hormonal
Hormone estrogen, progesteron and MSH can stimulate the formation of melasma.
Hormones have an important role in the human body. On the mask of pregnancy is known in terms obstetrik. Certain mechanisms of melasma because of the pregnancy has not been known. Estrogen level, progesterone, and Melanosit Stimulating hormone (MSH) generally increased in the third trimester. However, in nulipara with melasma, and MSH estrogen level does not increase. Then, the occurrence of melasma because the use of oral contraceptives and diethylstilbestrol used for prostate cancer therapy has also been reported. In the research, women who get menopause will progesteron experiencing melasma, while women who got estrogen not only suffering from melasma, so that it can be proved that progesterone a role in the occurrence of melasma.
One study found that patients with the disease tiroid suffering from melasma. A report of cases also reported that melasma can occur in patients who have experienced emotional stress because of increased MSH produki by hipotalamus.
3. Drugs
For example difenilhidantoin, mesantoin, klorpromasin, sitostatik and minosiklin can cause the occurrence of melasma. Drugs in this collectedthe top of the dermis layer and can stimulate cumulative melanonogenesis.
4. Genetic
Reported cases of family around 20-70%. Genetic factors is a major occurrence of melasma. This occurred mainly in women than men. A person with brown skin and the young sun exposure will increase the excess occurrence of melasma. More than 30% of patients have melasma history of the family who suffered the same aberration. Identical twin trends have also been reported suffering from melasma.
5. Race
Melasma many found in the Hispanic and the dark skin color.
6. Cosmetics
Use of cosmetics that contain perfume, coloring matter or materials that can cause fotosensitivitas which can lead to the emergence hiperpigmentasi in the face if exposed sun.
7. Certain conditions, such as pregnancy and hormone replacement therapy during menopause.
8. Idiopatik.
Pathogenesis melasma is not yet clear, many factors that are considered causative role in pathogenesis melasma.
According Supardiman (2007), pathogenesis the occurrence of melasma involves many factors, such as:
1. Increased production of hormones or because melanosom because ultraviolet rays. Melanosom this increase can also be caused pharmacology materials such as silver and psoralen.
2. Retardation in Malphigian cell turnover. This condition can occur because drugs sitostatika.
Pathogenesis melasma associated with many different fields of science, such as biology, biochemistry, pathology, and patofisiologi process pigmentasi skin, both at the cellular level, biomolekular, skin and tissue. In addition, knowledge of the pathogenesis is very important to establish the diagnosis and treatment.
No comments:
Post a Comment