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What Are The Causes of Pigmented Skin?

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Pigmented spots can be a source of frustration and concern. Find out why they occur, when to seek help and how to prevent them from troubling you.

Pigmented spots come in all shapes, sizes and colours. While many are harmless, they can mar the smooth and unblemished look of skin. Excessive pigmentation – known as hyperpigmentation – occurs when there is a problem with the production of melanin.

Produced by skin cells, melanin is the pigment that gives skin, eyes and hair their brown or black colour. Melanin also plays a role in protecting the skin against ultraviolet rays.

Overzealous melanin

Hyperpigmentation is due to an abnormally high concentration of melanin, melanocytes (cells that produce melanin) or hyperactive melanocytes. While hyperpigmentation can affect anyone, the condition is more prevalent among those of Asian, Mediterranean, African, or Latin ethnicities and can appear in any part of the body.

The appearance of hyperpigmentation depends on where melanin-producing cells are concentrated in the layers of the skin. They can be confined to the epidermis (the outermost layer of skin), the dermis (the layer beneath the epidermis) or both.

Common causes of hyperpigmentation include:

Freckles: superficial pigmentation found in the epidermis
Sun spots and flat age spots: pigmentation that occurs in the epidermis and extends into the dermis
Papular (bumpy) age spots: pigmentation that is confined to the epidermis but sticks out above the level of the skin
Post-inflammatory hyperpigmentation: pigmentation that remains following inflammatory conditions such as acne and insect bites

Melasma: pigmentation that is distributed symmetrically on both sides of the face. The brown patches can occur in the epidermis, dermis or both
Hori’s Naevus: brown-violet pigmentation patches usually found on the upper cheeks and common among people of Oriental descent (Chinese, Koreans and Japanese). The melanin is located in the dermis
Nevus of Ota: blue-black birthmark on the side of the face. The pigmentation can also occur on the whites of the eye

Triggers and prevention

Overproduction of melanin happens for several reasons. For instance, freckles and sun spots develop from a combination of genetics and sun exposure. In some people with an increased tendency towards freckles, exposure to ultraviolet causes the epidermis to thicken and this stimulates melanocytes to produces more melanin. Freckles are more common in those of Caucasian descent and people with light-coloured hair and eyes, and fair skin.

AGE SPOTS are dark patches that occur due to a combination of sun exposure and age-related changes in the skin. These spots do not occur solely in areas exposed to the sun but other parts of the body as well.

These spots need not be due to deliberate sun-tanning, but prolonged exposure to ambient ultraviolet rays in the environment aggravate them. The longer the exposure, the darker the spots tend to be.

MELASMA is a type of patchy discolouration on both sides of the face, believed to be linked to fluctuations in female hormones. These spots often arise during pregnancy or upon starting oral contraceptives. They can also be triggered by certain cosmetics, excessive exposure to the sun, as well as oral medications that cause sun-sensitivity.

POST-INFLAMMATORY HYPERPIGMENTATION is the result of a “spillage” of excessive melanin into the area of inflammation. The excess melanin results in darkening of the skin even after the inflammation has resolved. This is a normal response of the skin to inflammation and is especially apparent in people of certain ethnic origins, such as East and South-east Asians. Often, the more intense the inflammation and the longer the duration of the inflammatory process in the skin, the darker the subsequent pigmentation. Post-inflammatory hyperpigmentation can be caused by acne, insect bites and trauma to the skin.

NAEVI OF OTA are inherited congenital conditions that cannot be prevented.

The best way to prevent other forms of hyperpigmentation – such as FRECKLES, SUN SPOTS and AGE SPOTS – is to avoid prolonged exposure to ultraviolet rays. This underscores the importance of adequate daily sunblock and when engaging in outdoor activity to ensure protection from ultraviolet rays. To prevent post-inflammatory hyperpigmentation, avoid picking and squeezing acne spots or insect bites as this can intensify the inflammation and result in darker scars.

Early treatment to reduce the severity of inflammatory conditions can be useful to minimise consequent pigmentation.

Fading spots

Prescription-grade creams and lotions can lighten certain types of pigmentation although results vary depending on the nature and extent of the pigmentation. For superficial pigmentation (due to melanin present only in the top layer of the skin), topical lightening agents, chemical peels and Intense Pulsed Light (IPL) can be quite effective. Mild cases of postinflammatory hyperpigmentation, for instance, are particularly responsive to treatment. For pigment that is deeper, laser therapy is often recommended because lasers can better penetrate the deeper layers of the skin.

One of the most challenging conditions to treat is melasma because the response to treatment can be unpredictable. Treatment has to be calibrated meticulously and careful monitoring is essential to obtain an optimal response to therapy.