Disorders of Pigmentation

Pigmentation of the skin plays a significant role in one’s appearance and sense of well being. Disorders of pigmentation can cause stress and embarrassment. Skin colour results from the presence of melanin, produced by skin cells called melanocytes. The amount and distribution of melanin is responsible for human skin colour. In darker skinned individuals, melanocytes produce more melanin, and they undergo degradation more slowly than in lighter skinned people. UV irradiation results in increased production of melanin causing tanning. Disorders causing increased pigmentation may affect people of all skin colours, but they afflict darker skinned individuals more commonly. A few such conditions are discussed.

Melasma

This is a commonly encountered disorder of pigmentation. It is referred to as the “mask of pregnancy” as it most commonly appears during pregnancy, although it can also be caused by taking the oral contraceptive pill. It appears as blotches of pigmentation on the face, in areas of sun exposure. The most likely factors causing this problem are oestrogen and UV light. Melasma rarely abates spontaneously, and is often challenging to treat. Sun avoidance and the use of a high SPF sunscreen are necessary to protect against further melanin production. The melasma itself can be treated with skin lightening creams and chemical peels.

Post-inflammatory hyperpigmentation (PIH)

Any affliction of the skin eg. acne, eczema and trauma may result in PIH in susceptible individuals. It appears as irregular darkly pigmented spots occurring in areas of previous inflammation. It occurs due to increased melanin synthesis being produced in response to an insult to the skin. This condition is difficult to treat because affected individuals develop PIH following inflammation, It can be treated by peels and skin depigmenting creams.

Under eye circles

The causes of this very common complaint are poorly understood. Once again, sun avoidance and protection are necessary. If the areas under the eyes are hollow, the injection of hyaluronic acid filler may help alleviate the appearance of dark circles. Chemical peels and depigmenting creams are generally used to treat this condition.

Hydroquinone has traditionally been used as a depigmeting agent, however, its undesirable side effects limit its use. Many naturally occurring compunds found in plants have been discovered to lighten skin by inhibiting the production of melanin. These include (but are not limited to) azelaic acid, phytic acid, resorcinol, kojic acid, licorice extract, resveratrol and arbutin.