Another form of skin discoloration is called melasma. It is more prevalent in women, especially those who are pregnant, or are taking oral contraceptives or hormone replacement therapy. If freckles are more dominant in red heads (people with red hair), melasma is more common in dark-skinned races such as Hispanics, Indians, Asians, people from the Middle East and Northern Africa.

Melasma is caused by the stimulation of melanocytes or pigment-producing cells by the female hormones. People with thyroid disease also tend to develop melasma. It appears as dark patches on the face or forearms, and is triggered by sun exposure and UV radiation from light bulbs.

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