Melasma

Melasma is a hipermelanoza gained in areas exposed to sunlight. It presents as symmetric hyperpigmented macules, which can be confluent or dashed. The most common localizations are the cheeks, forehead, upper lip, chin, but occasionally can occur in sun-exposed areas. Chloasma is a synonymous term used to describe the occurrence of melasma during pregnancy. Chloasma derives from the Greek word "chloazein" means "being green". "MELAS" in Greek also means "black." Since the green color of the skin is melasma preferred term.
The most important factor in the appearance of melasma is exposure to sunlight. Melasma tends to occur in pregnancy and in women who oral contraceptives, although it can occur in anyone. The disease is more common in sunny climates and among people with darker skin.Dark spots, irregular skin, usually on both sides of the face. Pigmentation occurs frequently in the center of the face and cheeks, forehead, upper lip and nose. Sometimes the spots are found only on one side of the face. The spots are not itchy or painful and have only cosmetic importance.
If the skin is protected from the sun, melasma fades after pregnancy or after stopping oral contraceptives. People with melasma can use creams with SPF on stains and avoid sun exposure to prevent worsening of the condition. Skin whitening creams and retinoic acid can hidroquinona closed white spots.
Pathogenesis and causes
Pathophysiology of melasma is uncertain. In many cases this seems to be a direct relationship between female hormonal activity because the condition occurs in pregnancy and oral contraceptive use. Other factors are involved in the etiopathogenesis malesmei photosensitising drugs, mild ovarian or thyroid dysfunction, and certain cosmetics. The most important factor in the development of melasma is exposure to sunlight. Without the strict avoidance of sunlight potential success of treatments for melasma are doomed to failure.
Genetic predisposition.It is a major factor in the development of melasma. It is more common in women than in men. People with brown skin types from regions of the world with intense sun exposure are more likely to develop melasma. Over 30% of patients have a family history.
Exposure to the sun.Another major factor is exposure to sunlight. Ultraviolet radiation can cause lipid peroxidation of cell membranes, leading to excessive generation of free radicals that stimulate melanocytes to produce melanin in excess. SPF creams that block UV-B are especially poor because UV-A and visible light also stimulates melanocytes to produce melanin.
Hormonal influences.Pregnancy mask is well known in obstetrical patients. The exact mechanism by which pregnancy affects melasma is unknown. Estrogen, progesterone and melanocitic stimulating hormone (MSH) are normally kept in the third semester of pregnancy. However, nulliparous patients with melasma have no increased levels of estrogen and MSH. In addition, the incidence of melasma with estrogen and progestin contraceptives and diethylstilbestrol treatment for prostate cancer has been reported. The observation that postmenopausal women receiving progesterone develop melasma, while those receiving only estrogen progesterone does not involve playing a critical role in the development of melasma.