Melasma (Greek: “a black spot”) is an acquired light – or dark-brown hyperpigmentation that occurs in the exposed areas, most often on the face, and results from exposure to sunlight; may be associated with pregnancy, with ingestion of contraceptive hormones, or possibly with certain medications such as diphenylhydantoin, or may be idiopathic.
Causes of Melasma
Unknown. Estrogen preparations alone, however, given to postmenopausal women do not cause melasma, despite sun exposure. However, pregnancy causes melasma, and combinations of estrogen and progestational agents, as used for contraception, are the most frequent cause of melasma.
Symptoms of Melasma
Melasma doesn’t cause any other symptoms besides skin discoloration but may be of great cosmetic concern.
A uniform brown color is usually seen over the cheeks, forehead, nose, or upper lip. It is most often symmetrical (matching on both sides of the face).
Diagnosis
Melasma is usually diagnosed visually or with assistance of a Wood lamp (340 – 400 nm wavelength). Under Wood lamp, excess melanin in the epidermis can be distinguished from that of the dermis.
Treatment
Topical Two commercially available topical treatments (in the United States) are (1) 3% hydroquinone solution used in combination with topical .025% tretinoin gel and (2) a new combination of 4% hydroquinone and glycolic acid in a cream base; both of these are effective.
Under no circumstances should monobenzylether of hydroquinone or the other ethers of hydroquinone (monomethyl- or monoethyl-) be used in the treatment of melasma because these drugs can lead to a permanent loss of melanocytes with the development of a disfiguring spotty leukoderma. These drugs are limited to the treatment of extensive vitiligo in older persons to depigment the remaining normal pigment and provide one skin color, and eliminate the “harlequin” appearance of subtotal vitiligo.
Prevention It is essential that the patient use, every morning, an opaque sunblock containing titanium dioxide and/or zinc oxide; the action spectrum of pigment darkening extends into the visible range, and even the potent (with high SPF) transparent sunscreens are completely ineffective in blocking visible radiation.
Prevention
Daily sunscreen use not only helps prevent melasma but is crucial in the prevention of skin cancer and wrinkles.
References