Hyperpigmentation in skin is caused by an increase in melanin, the substance in the body that is responsible for color (pigment). Certain conditions, such as pregnancy or Addidons disease (decreased function of the adrenal gland), may cause a greater production of melanin and hyperpigmentation. Exposure to sunlight is a major cause of hyperpigmentation, and will darken already hyperpigmented areas. Generally there are 2 categories: superficial (epidermal) and deep (dermal). Examples of superficial pigmentation are freckles and lentigines. Common deep pigmentation including Nevus of Horis, Post inflammatory Hyperpigmentation (PIH) and Nevus of Ota. Superficial pigmentations are easier to manage compare to deep pigmentation.
Melasma is a benign skin disorder characterized by irregular patches of pigmentation on sun-exposed areas of the face. The condition is most common in adult females, who comprise approximately 90% of known cases. Although there are many clinical manifestations of melasma, it is generally considered to be a chronic condition with progression of disease if left untreated. Melasma occurs as a result of upregulated melanocytes that produce irregular patches of hyperpigmentation on the skin.
It is believed that a combination of sun exposure, hormones and genetic susceptibility lead to the development of the characteristic blotchy skin associated with melasma.