What Causes Skin Pigmentation to Change
Skin pigment changes can be dramatic. Both hyperpigmentation and hypopigmentation qualify as skin pigment changes. Find out what causes these changes and read about vitiligo, the most popular skin pigmentation disorder.
by Brad Chase
Skin pigmentation is the term used to describe the natural color of the skin. Human skin color is determined by melanin, the pigment found in the skin.
Melanin is produced by melanocytes which are specialized pigment cells found in the skin. Besides skin color, melanin is also responsible for the colors of the eyes and hair.
The production of melanin is triggered by the enzyme, tyrosinase.
There are 2 types of melanin: eumelanin, which is responsible for very dark brown coloration, and pheomelanin, which is responsible for red coloration. Therefore, the skin color depends on the amount of melanin produced and the population of melanocytes in the skin.
Human skin colors range from white to black and they are largely determined by genetics.
Skin pigment serves a protective purpose in the skin. It partially protects the skin from damage by direct ultraviolet irradiation. Therefore, skin color changes to reduce the amount of UV radiation penetrating the skin. Such radiation can damage the DNA of skin cells and cause cancerous mutations.
However, incident UV radiation is not the only factor that can change skin color. Other factors known to modify skin pigmentation are temperature, infections, skin cancer and dietary changes.
There are 2 types of skin pigmentation changes: hyperpigmentation and hypopigmentation.
When there is an increased production of melanin in the skin, hyperpigmentation results. It is the unusual darkening of the skin, even the hyperpigmented areas of the skin.
The chief cause of hyperpigmentation is prolonged exposure to intense ultraviolet light especially sunlight. However, hyperpigmentation can also be caused by certain physiological states such as pregnancy; diseases such as Addison’s disease; and drugs including sulfa drugs.
Melasma is a good example of hyperpigmentation of the skin.
Melasma is also called cholasma, cholasma faciei or mask of pregnancy. It can affect both men and women.
Melasma presents as dark or tan discolorations on the skin. Its irregular, hyperpigmented macules are usually found on the face and they expand over time. However, when it affects pregnant women, it usually goes away after the pregnancy.
Melasma can be caused by hormonal changes and it is commonly seen in women taking oral contraceptives or undergoing estrogen replacement therapy.
Melasma is only a cosmetic discoloration and not an actual disease. Those who have it are advised to wear strong sunscreens. It can be treated with hydroquinone cream, topical tretinoin, azelaic acid, chemical peels, microdermabrasion and laser therapy.
Hypopigmentation is the reverse of hyperpigmentation. It is caused by reduced melanin production.
The two most common forms of hypopigmentation are albinism and vitiligo.
Albinism is a genetic disorder with no cure. Albinism is a complete lack of skin pigmentation which is caused by defect in the genes coding for the enzyme that produces melanin.
Vitiligo is an autoimmune disorder caused by the destruction of the melanocytes in the skin by immune cells. It presents as white patches of depigmented areas of the skin.
Vitiligo has no cure but there are treatments to stop its progression and even regain some skin pigmentation.
Although most skin pigmentation disorders can be differentiated by simple visual examinations, there is often a need for clinical workups and laboratory tests.
One common test used for diagnosing skin pigmentation disorders is the Wood’s Lamp Examination.
This test is done in a darkened room and it involves shinning ultraviolet light from a special lamp on your skin. This test is especially useful for determining the bacterial or fungal cause of skin pigmentation changes.
Skin biopsy is another test that is commonly used for this purpose. It involves taking a tiny section of the skin and examining it under the microscope. This test can provide detailed information to effectively diagnose the sub-type of a skin pigmentation disorder, its stage of progression and the extent of damage done to the skin.
For pigmentation disorders caused by drugs, allergies, hormonal changes and autoimmune factors, specialized blood tests may be done to look for drug metabolites, inflammatory factors, antibodies and also measure hormonal levels.
Vitiligo is a skin pigment disorder caused by the progressive destruction of melanocytes.
Vitiligo affects 1 in 100 people; 1 out of every 3 vitiligo patients inherits the condition; and 5 – 7% of vitiligo patients directly inherit the condition from their parents. Most cases of vitiligo occur between the ages of 20 and 40.
It affects both sexes equally and people of all races equally. However, vitiligo is most noticeable in dark-skinned people.
The main presentations of vitiligo are white patches on the skin.
These patches first appear small but soon grow in size and shape. The rate and extent of expansion of vitiligo patches are difficult to determine. Sometimes, the first spots never expand but they can also rapidly spread to other parts of the body.
Vitiligo patches first appear on the face, neck, scalp, hands and wrists. It can also spread to the trunk and limbs. These patches are especially found around the orifices of the body including the eyes, nostrils, lips, nipples, navel, genitals and rectum.
Vitiligo is not painful or contagious; it does not itch or produce any other systemic effects except where they are complications or where it presents with other autoimmune disorders.
However, since vitiligo patches are depigmented areas of the skin, they are more prone to sunburn than healthy, normal skin. In addition, since melanin is also found in the eyes and ears, specialist consultation may be needed in moderate to severe vitiligo cases.
Although vitiligo patients are altogether healthy, the changed appearance of the skin can cause psychological distress. Therefore, counseling with a therapist should be an essential part of vitiligo treatment.
Although the exact root causes of vitiligo are unknown, studies have shown that vitiligo can be caused by autoimmune attack on melanocytes, toxic chemicals, oxidative stress, defective melanocytes, genetic defects and nerve damage.
Autoimmune Attack on Melanocytes: This is usually the cause of vitiligo associated with other autoimmune diseases especially thyroid disorders. When the cells of the immune system go on a rampage, the melanocytes are one of the targets.
Once destroyed, vitiligo quickly sets in. This autoimmune attack on the skin can also cause psoriasis and alopecia areata.
Oxidative Stress: The accumulation of harmful free radicals and hydrogen peroxide in the skin has been shown to increase the rate of death of melanocytes. When this oxidative stress overwhelms the skin, the levels of antioxidant enzymes such as catalase are reduced.
Vitiligo caused by oxidative stress can be clinically distinguished by the yellowish green or blue fluorescence of the skin under special light.
Defective Melanocytes: Improperly formed melanocytes are more easily destroyed than normal melanocytes. This theory suggests that vitiligo affects people who have these malformed melanocytes. The cellular abnormality can be structural (rough endoplasmic reticulum) or functional (dysregulation of surface receptors).
Nerve Damage: There have been vitiligo cases that arise only after some nerve damage. Therefore, some experts believe that the change in neurochemical mediators released at nerve endings can affect the production of melanin and cause vitiligo.
Genetic Defects: Multiple genetic defects may increase the risk of developing vitiligo in certain people. Genes play significant role in formation of melanocytes, synthesis of melanin, protection against oxidative stress and regulation of autoimmune response.
Therefore, a genetic defect in any of these processes can cause vitiligo.
There are 3 treatment goals for vitiligo. These are:
Camouflaging works especially during the early stages of vitiligo and when there are only a few white patches. It can be achieved with make-ups, cover creams and self-tanning lotions.
There are various options for repigmenting the skin. The first step for most vitiligo patients is the use of steroid creams. These should not be used for long-term treatment because of the side effects they cause.
Tacrolimus and pimecrolimus creams are safer and are prescribed for children.
Natural vitiligo products are also available. They produce far less side effects and are just as effective. These natural remedies include vitamins, minerals and herbal extracts with antioxidant and immunomodulatory properties. A good example of drugs in this class is callumae.
The 3 light treatments used in treating vitiligo are PUVA (psoralen ultraviolet A therapy), narrow band UVB and excimer laser. These are expensive and time-consuming but effective.
Alternatively, surgical treatments are available. The 2 most common surgical vitiligo treatments are autologous skin grafting and autologous melanocyte grafting.
Full-body depigmentation is only recommended when vitiligo patches cover more than half the body.
This form of depigmentation is irreversible and turns the skin completely white. It is achieved by topical application of mononbenzone.
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Callumae is a Vitiligo Remedy designed to help get rid of white spots on your skin. Use in conjuction with light therapy (or natural sun light) to help get the most repigmentation to your skin.