Melasma means a ‘black spot’ and chloasma a ‘green spot’ in Greek. It is usually associated with pregnancy; hence the nickname, the mask of pregnancy. Melasma can occur due to other causes also.
What are the Causes of Melasma?
In addition to pregnancy, melasma also occurs following use of oral contraceptive pills and certain medications like diphenylhydantoin. Melasma appears in menopausal women who had been treated with hormone replacement therapy to avoid osteoporosis or bone demineralization.
About 10% of melasma occur in males, when it is called solar melanosis. Melasma has also been found to occur after severe stressful periods in both males and females.
Exposure to sunlight or UV rays is a prerequisite for the development of melasma.
The dark brown hyperpigmentation in melasma is due to increased production of melanin pigment in the sun exposed areas. The origin of melasma involves a number of steps, including hormonal stimulation of the melanocytes to produce more pigment and sun exposure.
Why is Melasma Prominent on Certain Areas of the Face Only?
The central part of the face, cheeks, nose, and forehead contain maximum number of melanocytes. The sun rays fall directly on these exposed areas of the face. This is the reason why melasma is common on certain areas of the face. Melasma is also one of the commonest disorders of skin color.
What are the Types of Melasma?
Melasma can be classified according to the depth of melanin deposition in the skin.
- Epidermal melasma: This causes a light brown superficial pigmentation. Easier to treat.
- Dermal melasma: This is deeper and causes a darker bluish brown or black discoloration of the skin. Dermal melasma is difficult to get rid off.
- Dermo-epidermal melasma: This is a combination of the above, with dark skin discoloration varying according to the depth of melanin deposition.
The depth of the melasma pigmentation can be ascertained through wood’s lamp examination. Pressing on the melasma patch with a glass slide (where the superficial pigment lightens), is an alternative, easier way to differentiate both types.
How to Treat Melasma?
- Prevention of exacerbation of the skin darkening is part of the treatment and involves use of opaque sun blocks containing titanium dioxide or zinc oxide. The transparent chemical sunscreens are ineffective in preventing melasma, as these do not block the visible sun rays, which are also partly responsible for the pigmentation.
- Melasma treatment also includes avoidance of provocative factors like oral contraceptive pills, other medications and cosmetics.
- Topical therapy involves application of topical skin lightening agents like hydroquinone 2-4%, azelaic acid 20%, kojic acid, licorice extracts, arbutine, vitamin C, niacinamide etc. As hydroquinone is sun sensitive it should be applied only at night. Addition of glycolic acid and topical retinoids increase the penetration and exfoliative effects of the applications. Sometimes, moderate strength topical steroids are also used in combination with the skin lighteners.
- Skin Peels, performed on a regular basis are useful in getting rid of more resistant cases of melasma. Examples of commonly used peels are Glycolic acid 20-70%, Miami peel (containing salicylic acid, hydroquinone, lactic acid, kojic acid and citric acid) and TCA (trichlor acetic acid) peels.
- Laser treatments, especially with the fractional lasers, are the new additions to the therapeutic armamentarium of melasma.
What is the Course and Prognosis of Melasma?
Melasma, as the mask of pregnancy, goes away by itself in a few months after delivery. Drug induced melasma fades away after stoppage of the culprit medication. Other types may recur after successful treatment if the triggering factors are re-applied. Hence lifelong sun blocks are advisable even after successful treatment of melasma.
Reference
- Pigmentary Disorders. IADVL Text Book and Atlas of Dermatology, Bhalani Publishing House, Mumbai; 2003.
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