ሌላው መልስ ያገኘሁት ስለዚሁ ስለ ማድያት ( Melasma ) በዝርዝር የሚያወራ ድህረ ገጽ ማጣቀሻ ነው::
ዋናው ገጽ ማጣቀሻ - http://www.medicinenet.com/melasma/article.htm#
ከዚሁ ድህረ ገጽ ጠቃሚ ያልኩዋቸውን ገጾች ወደዚህ አምጥቻቸዋለሁ::
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What is melasma? What are signs of melasma?
Melasma is a very common patchy brown, tan, or blue-gray facial skin discoloration, almost entirely seen in women
in the reproductive years. It typically appears on the upper cheeks, upper lip, forehead, and chin of women 20-50 years of age. Although possible, it is uncommon in males. It is thought to be primarily related to external sun exposure, external hormones like birth control
pills, and internal hormonal changes as seen in pregnancy
. Most people with melasma have a history of daily or intermittent sun exposure. Melasma is most common among pregnant women, especially those of Latin and Asian descents. People with olive or darker skin, like Hispanic, Asian, and Middle Eastern individuals, have higher incidences of melasma.
An estimated 6 million women are living in the U.S. with melasma and 45-50 million women worldwide live with melasma; over 90% of all cases are women. Prevention is primarily aimed at facial sun protection and sun avoidance. Treatment requires regular sunscreen
application and fading creams.
What causes melasma?
The exact cause of melasma remains unknown. Experts believe that the dark patches in melasma could be triggered by several factors, including pregnancy, birth control pills, hormone replacement therapy
(HRT and progesterone), family history of melasma, race, antiseizure medications, and other medications that make the skin more prone to pigmentation after exposure to ultraviolet (UV) light. Uncontrolled sunlight exposure is considered the leading cause of melasma, especially in individuals with a genetic predisposition to this condition. Clinical studies have shown that individuals typically develop melasma in the summer months, when the sun is most intense. In the winter, the hyperpigmentation in melasma tends to be less visible or lighter.
When melasma occurs during pregnancy, it is also called chloasma, or "the mask of pregnancy
." Pregnant women experience increased estrogen, progesterone, and melanocyte-stimulating hormone (MSH) levels during the second and third trimesters of pregnancy. However, it is thought that pregnancy-related melasma is caused by the presence of increased levels of progesterone and not due to estrogen and MSH. Studies have shown that postmenopausal women who receive progesterone hormone replacement therapy are more likely to develop melasma. Postmenopausal women receiving estrogen alone seem less likely to develop melasma.
In addition, products or treatments that irritate the skin may cause an increase in melanin production and accelerate melasma symptoms.
People with a genetic predisposition or known family history of melasma are at an increased risk of developing melasma. Important prevention methods for these individuals include sun avoidance and application of extra sunblock to avoid stimulating pigment production. These individuals may also consider discussing their concerns with their doctor and avoiding birth control pills and hormone replacement therapy (HRT) if possible.
Where is melasma seen on the body?
Melasma is characterized by discoloration or hyperpigmentation primarily on the face. Three types of common facial patterns have been identified in melasma, including centrofacial (center of the face), malar (cheekbones), and mandibular (jawbone).
The centrofacial pattern is the most prevalent form of melasma and includes the forehead, cheeks, upper lip, nose, and chin. The malar pattern includes the upper cheeks. The mandibular pattern is specific to the jaw.
The upper sides of the neck may less commonly be involved in melasma. Rarely, melasma may occur on other body parts like the forearms. One study confirmed the occurrence of melasma on the forearms of people being given progesterone. This was a unique pattern seen in a Native American study.
What are the types of melasma?
Four types of pigmentation patterns are diagnosed in melasma: epidermal, dermal, mixed, and an unnamed type found in dark-complexioned individuals. The epidermal type is identified by the presence of excess melanin in the superficial layers of skin. Dermal melasma is distinguished by the presence of melanophages (cells that ingest melanin) through out the dermis. The mixed type includes both the epidermal and dermal type. In the fourth type, excess melanocytes are present in the skin of dark-skinned individuals.
How is melasma diagnosed?
Melasma is usually readily diagnosed by the typical appearance of brown skin patches on the face. Dermatologists are physicians who specialize in skin disorders and often diagnose melasma by visually examining the skin. A black light or Wood's light (340-400 nm) can assist in diagnosing melasma. In most cases, mixed melasma is diagnosed, which means the discoloration is due to pigment in the dermis and epidermis. Rarely, a skin biopsy
may be necessary to help exclude other causes of this local skin hyperpigmentation.
What is the treatment for melasma?
The most common melasma therapies include 2% hydroquinone
(HQ) creams like the over-the-counter products
Esoterica and Porcelana and prescription 4% creams like Obagi Clear, Glyquin, Tri-Luma
, and Solaquin. Products with HQ concentrations above 2% generally require a prescription. Clinical studies show that creams containing 2% HQ can be very effective in lightening the skin and less irritating than higher concentrations of HQ for melasma. These creams are usually applied to the brown patches twice a day. Sunscreen should be applied over the hydroquinone cream every morning. There are treatments for all types of melasma, but the epidermal type responds better to treatment than the others because the pigment is closer to the skin surface.
Melasma may clear spontaneously without treatment. Other times, it may clear with sunscreen usage and sun avoidance. For some people, the discoloration with melasma may disappear following pregnancy or if birth control pills and hormone therapy
In order to treat melasma, combination or specially formulated creams with hydroquinone, a phenolic hypopigmenting agent, azelaic acid, and retinoic acid (tretinoin
), nonphenolic bleaching agents, and/or kojic acid may be prescribed. For severe cases of melasma, creams with a higher concentration of HQ or combining HQ with other ingredients such as tretinoin, corticosteroids, or glycolic acid may be effective in lightening the skin.
- Azelaic acid 15%-20% (Azelex, Finacea)
- Retinoic acid 0.025%-0.1% (tretinoin)
- Tazarotene 0.5%-0.1% (Tazorac cream or gel)
- Adapalene 0.1%-0.3% (Differin gel)
- Kojic acid
- Lactic acid lotions 12% (Lac-Hydrin or Am-Lactin)
- Glycolic acid 10%-20% creams (Citrix cream, NeoStrata)
- Glycolic acid peels 10%-70%
Possible side effects of melasma treatments include temporary skin irritation. People who use HQ treatment in very high concentrations for prolonged periods (usually several months to years) are at risk of developing a side effect called ochronosis. Hydroquinone-induced ochronosis is a permanent skin discoloration that is thought to result from use of hydroquinone concentrations above 4%. Although ochronosis is fairly uncommon in the U.S., it is more common in areas like Africa where hydroquinone concentrations upward of 10%-20% may be used to treat skin discoloration like melasma. Regardless of the potential side effects, HQ remains the most widely used and successful fading cream for treating melasma worldwide. Regular medical follow-up appointments with a doctor are important for people using HQ treatment for melasma. HQ should be discontinued at the first signs of ochronosis.
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