Melasma / Chloasma

Melasma is a commonly acquired increase of pigmentation that occurs exclusively in sun-exposed areas. Brownish in color, it is exacerbated by sun exposure, pregnancy, oral contraceptives, and certain anti-epilepsy drugs.

Melasma is reasonably common, especially in women of child-bearing age. However, up to 10% of cases have been reported in males. While all races are affected, there is a prominence among Latinos and Asians. Melasma is more apparent during and after periods of sun exposure and less obvoius in winter months, when sun exposure is lacking.

Melasma presents itself in one of the three usually symetrical facial patterns. The most common is a centrofacial pattern involving the cheeks, forehead, upper lip, nose, and chin. Less common are the malar pattern, involving the cheeks and nose, and the mandibular pattern, involvong the ramus of the mandible (the side of the cheeks and jawline). Melasma also occurs on the forearms, but this is rare.

What is the Difference between Dermal and Epidermal Melasma?
Every case of melasma starts off in the epidermis, where melanocytes are actively producing pigment. A normal case of melasma can turn into dermal melasma if skin becomes over-irritated and inflamed. When this happens, it causes a temporary split between the dermis and epidermis. During this time, hyperpigmented cells can drop from the epidermis into the dermis. Once in the dermis, these cells become very resistant to topical treatment. This is one reason why it is so important to avoid aggressiveness in the treatment of melasma.

What are the Causes of Melasma?
Melasma has been considered to arise from pregnancy, oral contraceptives, endocrine dysfunction, genetic factors, medications, nutitional deficiency, hepatic dysfunction, and other factors. The majority of cases appear to be related to pregancy or oral contraceptives. The infrequency of melasma in postmenopausal women on estrogen replacement suggests that estrogen alone is not the cause. In more recent experience, combination treatment using estrogen plus progestational agents is being used in postmenopausal women, and melasma is being observed in some of these older women who did not have melasma during their pregnancies. Sun exposure would appear to be a stimulating factor in predisposed individuals. Although a few cases within families have been describe, melasma should not be considered a heriditary disorder.