Hyperpigmentation is a skin condition caused by ultraviolet light from the sun, which darkens the skin in color compared to the surrounding skin. This darkening occurs when an excess of melanin, the brown pigment that produces normal skin color, forms deposits in the skin as UV light provokes melanocytes in the skin.

It is a common, usually harmless condition which can affect the skin color of people of any race. However people with darker skin such as Asian, east Indian, Mediterranean or African skin tones are also more prone to hyperpigmentation especially if they have excess sun exposure. Age or "liver" spots are a common form of hyperpigmentation. These occur due to sun damage, and are referred to by doctors as solar lentigines. These small, darkened patches are usually found on the hands and face or other areas frequently exposed to the sun. Other causes of Hyperpigmentation are associated with a number of diseases and conditions.

What is hyperpigmentation?

Hyperpigmentation is a skin condition caused by ultraviolet light from the sun, which darkens the skin in colour compared to the surrounding skin. This darkening occurs when an excess of melanin, the brown pigment that produces normal skin colour, forms deposits in the skin as UV light provokes melanocytes in the skin. Age or "liver" spots are a common form of hyperpigmentation. These occur due to sun damage, and are referred to as solar lentigines. These small, darkened patches are usually found on the hands and face or other areas frequently exposed to the sun. Hyperpigmentation has multiple causes with most causes being due to an increase in melanin production and deposition.

Who is most affected by Hyperpigmentation?

Hyperpigmentation is a common, usually harmless condition, which can affect the skin color of people of any race. However people with darker skin such as Asian, east Indian, Mediterranean or African skin tones are also more prone to hyperpigmentation especially if they have excess sun exposure.

Causes of hyperpigmentation

1. Excessive sun exposure

2. Addison's disease and other sources of adrenal insufficiency, in which hormones that stimulate melanin synthesis (e.g. MSH) are frequently elevated.

3. Cushing's disease, excessive ACTH production; Melanocyte-Stimulating Hormone (MSH) production is a byproduct of ACTH synthesis from Pro-opiomelanocortin (POMC).

4. Melasma ( chloasma ), or patchy hyperpigmentation often found in pregnant women, women taking oral contraceptives, 10% of nonpregnant women and dark skinned men. It is usually found on the forehead, temples and cheeks. It usually fades slowly and completely after childbirth or cessation of hormone use. However in men, melasma slowly fades and incompletely after childbirth. In men, melasma rarely fades.

5. Linea nigra , a hyperpigmented line found on the abdomen during pregnancy

6. Certain chemicals such as salicylic acid, bleomycin , and cisplatin

7. Smoker's melanosis

8. Celiac Disease

Types of Hyperpigmentation

Focal hyperpigmentation

This form of hyperpigmentation is usually post-inflammatory in nature. Skin darkening is a common occurrence after irritation or injury to the skin, such as the after effects of waxing or hair removal or any kind of puncture to the skin, as well as cuts, burns and other causes of inflammation. This type of hyperpigmentation is more prominent in dark skin; however it can also be seen in individuals with lighter skin. After irritation or injury to the skin, the pigment cells (melanocytes) deposit pigment in both upper and lower layers of the skin. However these dark patches clear with time although they can last for months to years. If treatment is started immediately, this would help determine the outcome and ultimate appearance of the area.

Lentigines (Age or "liver" spots)

These are a common form of hyperpigmentation caused by sun damage. These are usually small, darkened patches found on the hands and face, or any areas typically exposed to the sun. They first appear during middle age and increase in number with age.

Melasma (chloasma)

These are similar in appearance to lentigines; however, they are larger areas of darkened skin which appear as a result of hormonal changes. They consist of dark brown, roughly symmetric patches of hyperpigmentation on the face, particularly the forehead, temples, and cheeks. This form of hyperpigmentation occurs primarily in pregnant women and women taking contraceptives. It is thought that about 10% of cases occur in women who are not pregnant and in dark-skinned men and its mechanism is thought to involve overproduction of melanin.

Diffuse hyperpigmentation due to systemic disorders

Systemic disorders which result in hyperpigmentation include Addison's disease, primary biliary cirrhosis, and hemochromatosis.

Drug-induced hyperpigmentation

These are caused by a number of mechanisms:

1. Increased melanin in the epidermis, appearing brown

2. Presence of melanin in the epidermis and high dermis, appearing mostly brown with a tint of grey and blue.

3. Increased melanin in the dermis, appearing greyish or blue

4. Dermal deposition of a drug or metabolite, appearing slate or bluish grey

(Taken from http://www.merck.com/mmpe/sec10/ch123/ch123d.html )

Treatment for hyperpigmentation

Intense pulsed light (IPL) therapy

IPL is a broad band visible light in the 500-1200nm range, that is emitted from a nonlaser filtered flashlamp in pulses (3). The light which is applied to the target area is absorbed by the cells that have a greater intensity of colour or chromophores (parts of a molecule responsible for its colour) i.e. the hyperpigmented area. This light energy is converted to heat energy which causes damage to the target cells thus causing the break-up of the hyperpigmented area (2). The use of filters in IPL therapy enables different wavelengths to be applied to the target area and therefore allows optimum wavelength to be selected for effectiveness against different target cells (1). The advantage of this therapy is that recovery time is quite fast as only the dermis (lower surface) of the skin is targeted (2). It has shown to be effective against such pigmentation as refactory melasma (darkened brown patches) (4), ephelides (freckles) and solar lentigines (liver spots) (3). IPL therapy can be obtained from clinics.

Topical therapies

A topical agent that is commonly used for treatment of hyperpigmentation is hydroquinone, which is often incorporated into bleaching creams. It acts as a de-pigmenting agent by inhibiting an enzyme that plays a role in melanin formation. A concentration of 4% hydroquinone is usually recommended by dermatologists. Although hydroquinone can be quite effective against hyperpigmentation, results may only be seen after long term treatment, and side effects such as irritant and allergic contact dermatitis and post inflammatory hyper- or hypopigmentation may arise (5).

Other topical agents that can reduce hyperpigmentation include tretinoin 0.1% cream which works by dispersing pigment granules and interfering with pigment transfer. The chemical Azelaic acid can prevent DNA synthesis in melanocytes. Although these agents can help reduce hyperpigmentation acting alone, combination therapy offers improved effectiveness (5).

Microdermabrasion

Of all the treatments available for getting rid of uneven skin tone, microdermabrasion is the least invasive. Microdermabrasion involves applying tiny rough grains to buff away the surface layer of the skin. This technique is used by various products and treatments, ranging from medical microdermabrasion which uses a flow of aluminum oxide micro crystals to scrubs which can be applied at home. Microdermabrasion is usually done to the face, chest, neck, hands or arms. It is more affordable than cosmetic surgery, has fewer side effects and is effective on all skin types and colours . Microdermabrasion is however only effective in mild cases of hyperpigmentation or dark spots.

Skin whitening products

These include bleaching creams, which contain hydroquinones and mild acids such as glycolic, kojic and retinoic acid. The effectiveness of skin lightening on hyperpigmentation does not rely solely on the products; in addition to these products, a good regimen should include sunscreen, vitamin C and moisturisers. Sunscreen should be worn at all times when outdoors regardless of the treatment being used. 500mg of vitamin C supplement helps decrease the production of melanin, which is the pigment responsible for skin tanning. Reduction of this pigment will help produce great results when using skin lightening products. Moisturisers will keep the skin hydrated whilst the skin lightening product is being used. It is essential to moisturise the skin during this period as skin lightening products have a mild drying effect, which is necessary to prepare the skin for exfoliation and peeling of dull and unwanted dark skin patches. It is advised that skin lighteners be applied before bedtime.