Pigment Disorders
(Albinism; Hyper- and Hypopigmentalion, Melanocyte or Pigmented Nevi, Melasma, Moles)
Pigment disorders are discolorations of the epidermis, the outermost layer of the skin, which gets its color from melanin, a chemical produced by a specific type of skin cells called melanocytes. The affected skin may appear bleached -- hypopigmented -- from insufficient melanin; or it may have become abnormally dark -- hyperpigmented -- due to excessive melanin.
A lack of melanin may be hereditary, the most extreme example of it is albinism, a genetic disorder in which melanocytes are present but do not produce melanin. People with albinism have white hair, pale skin, and pink eyes that are extraordinarily sensitive to light. They sunburn easily and are very susceptible to skin cancers.
When melanocytes are damaged, areas of hypopigmentation develop, ranging from small patches to large segments that cover most of the body. This condition, known as vitiligo, sometimes affects light-skinned people, but is more prevalent among those who are dark skinned. Between 2 and 5 percent of all African-Americans are affected. (The pop star Michael Jackson is one of the most famous examples.)
More commonly, bleached skin develops at the site of a healed injury such as a cut, burn, abrasion, or infection -- a condition called post-inflammatory hypopigmentation. Sometimes the opposite occurs and the skin darkens instead. This tends to happen to black people who have had severe acne.
A temporary loss of pigmentation, pityriasis alba, is a benign disorder in which small, smooth white patches appear, usually on the cheeks and arms. Though not painful, the spots may itch. They commonly occur in children and adolescents, and often come and go for years, generally disappearing entirely between ages 20 and 30.
By far the most common examples of hyperpigmentation are pigmented moles, the vast majority of which are harmless. Also, with age, most people develop so-called liver spots, or senile lentigines. These pigmented areas have nothing to do with the liver, but are caused by excessive exposure to sun. They too are generally benign. More serious is the widespread skin darkening that may result from the hormonal changes in Addison's disease, a life-threatening endocrine disorder.
Another harmless form of pigmentation is melasma gravidarum, or the mask of pregnancy, a manifestation of hormonal changes. Women with melasma develop patches of darkened skin, usually on the forehead, temples, or cheekbones, especially after exposure to sun. The patches generally disappear following childbirth, although the process may take several months.
Diagnostic Studies and Procedures
Abnormalities in pigmentation are readily apparent; a dermatologist can usually determine the condition simply by inspecting affected skin. To confirm a diagnosis, however, skin scrapings may be examined under a microscope.
Finding the underlying cause may require various tests, especially if it involves an organic disorder. Blood tests and hormonal studies will be ordered if Addison's disease or some other hormonal disorder is suspected.
Medical Treatments
Treatments vary according to the underlying problem, and for some, such as albinism, there is no medical treatment other than frequent checkups for skin cancer.
For treatable disorders, the goal is to make the discolorations less noticeable. Vitiligo, for example, may be treated either by repigmentation (restoring of the normal pigment) or depigmentation (destroying the remaining pigment). Neither of these approaches is totally satisfactory, and the degree of success varies from one person to another. Some dermatologists treat senile lentigines cosmetically with Retin A, a cream containing the vitamin A derivative tretinoin, which is said to have anti-aging properties.
The most frequently used approach for repigmentation is a combination of drug and light therapy. First, a psoralen drug, the type used to treat psoriasis, is taken internally. This is followed by exposure to ultraviolet light, either by sitting in the sun or under artificial lamps. When this drug is activated by the light, it stimulates repigmentation by increasing the availability of color-producing cells at the skin's surface. Treatment may go on for months, with a rest period usually taken during the winter. Protective sunglasses must be worn during exposure to the sun and throughout the day on which the psoralen drug is taken.
If vitiligo consists only of small, scattered patches, drugs to stimulate pigmentation may be applied directly to the affected skin. These areas are then exposed to sunlight, taking care to avoid overexposure, because the treatment makes a person highly susceptible to severe sunburn and blistering.
Anyone who has vitiligo covering more than half the body is not considered a good candidate for repigmentation. Instead, the person may try depigmentation, aimed at making the patches less noticeable by bleaching the rest of the skin. Bleaching agents such as hydroquinone (Solaquin Forte) may be prescribed. A sunblock must be used because exposure to ultraviolet rays will cause repigmentation. Allergic reactions to the drug also are common.
Pityriasis alba is usually treated with hydrocortisone creams, which may be applied to the affected patches of skin once or twice a day.
When melasma gravidarum persists after childbirth, the condition may be treated with hydroquinone to decrease the pigmentation, provided there is no allergic reaction when the substance is tested on a small patch of skin. Some doctors may prescribe hydroquinone combined with Retin A to enhance its effects. These drugs should never be used during pregnancy.
Alternative Therapies
No effective alternative therapies exist for stimulating pigmentation, but there are numerous remedies for hyperpigmented areas, especially those that develop with age.
Herbal Medicine. Aloe vera gel is said to bleach age spots. Many herbalists advocate rubbing them with a fresh piece of aloe, rather than using commercial preparations, which often contain very little aloe vera. An alternative remedy calls for rubbing a spot for a few minutes twice a day with the milky sap from crushed dandelion stems. A paste made of dried comfrey root is also said to bleach pigmented spots. Leave the paste on for 20 minutes, and then rinse off with lemon juice.
Nutrition Therapy. Vitamins A, C, D, and E are believed to help protect the skin from damage and perhaps hyperpigmentation caused by ultraviolet radiation. Use vitamin A supplements with caution; too much can damage the liver. High doses of vitamin A can also cause serious birth defects; supplements and drugs containing vitamin A or its derivatives should not be used during pregnancy and should be stopped at least three months before attempting to conceive a child.
Self-Treatment
Avoiding sunburn is fundamental to self-treatment of most pigment disorders, especially albinism. People with this condition -- as well as those with vitiligo -- should stay out of the sun as much as possible and always wear protective clothing and use a sunscreen with a sun protection factor of 15 or more on skin that is exposed to sunlight. People with albinism should also I wear sunglasses that screen out 100 percent of ultraviolet rays. In fact, many are so sensitive to light that they must wear dark glasses even indoors. The right combination of cosmetics can be very effective in concealing or de-emphasizing affected patches of skin
for both hyperpigmentation and hypopigmentation disorders. However, anyone with sensitive skin should use hypoallergenic products to minimize the risk of allergic reactions.
To avoid or reduce post-inflammatory hyperpigmentation from acne, treat the skin gently during eruptions. Avoid picking, harsh scrubbing, and abrasive products unless they are prescribed by a physician. In general, washing with soap and water is sufficient to cleanse skin affected by acne.
A word of caution. Most over-the-counter bleaching creams and lotions that are advertised as freckle and spot removers are not effective and may irritate the skin, causing an allergic reaction. Anyone interested in commercial bleaching products, dyes, and stains should consult a dermatologist for the names of suitable products.
Other Causes of Pigment Disorders
In addition to Addison's disease, darkening of the skin may be caused by high-estrogen birth control pills and other hormonal preparations. Light skin spots may be due to tinea versicolor, a fungal infection that starts as small spots scattered over the upper arms, chest, and back. The spots expand slowly and are more noticeable on dark skin where they appear as white to pale tan. On light skin they may not be recognized or may appear as tan to pink spots. This disorder is treated with antifungal creams or pills.