Melasma (also known as chloasma faciei, or the mask of pregnancy when present in pregnant women) is a tan or dark skin discoloration. Although it can affect anyone, melasma is particularly common in women, especially pregnant women and those who are taking oral or patch contraceptives or hormone replacement therapy (HRT) medications.
Video Melasma
Signs and symptoms
The symptoms of melasma are dark, irregular well demarcated hyperpigmented macules to patches commonly found on the upper cheek, nose, lips, upper lip, and forehead. These patches often develop gradually over time. Melasma does not cause any other symptoms beyond the cosmetic discoloration. Melasma is also common in pre-menopausal women. It is thought to be enhanced by surges in certain hormones.
Maps Melasma
Cause
Melasma is thought to be the stimulation of melanocytes (cells in the epidermal layer of skin that produce a pigment called melanin) by the female sex hormones estrogen and progesterone to produce more melanin pigments when the skin is exposed to sun. Women with a light brown skin type who are living in regions with intense sun exposure are particularly susceptible to developing this condition.
Genetic predisposition is also a major factor in determining whether someone will develop melasma.
The incidence of melasma also increases in patients with thyroid disease. It is thought that the overproduction of melanocyte-stimulating hormone (MSH) brought on by stress can cause outbreaks of this condition. Other rare causes of melasma include allergic reaction to medications and cosmetics.
Melasma Suprarenale (Latin - above the kidneys) is a symptom of Addison's disease, particularly when caused by pressure or minor injury to the skin, as discovered by Dr. FJJ Schmidt of Rotterdam in 1859.
Diagnosis
Melasma is usually diagnosed visually or with assistance of a Wood's lamp (340 - 400 nm wavelength). Under Wood's lamp, excess melanin in the epidermis can be distinguished from that of the dermis.
Differential diagnosis
- Post inflammatory hyperpigmentation
- Actinic lichen planus
- Hydroquinone-induced exogenous ochronosis (see Ochronosis#Treatments of Exogenous Ochronosis)
Treatment
The discoloration usually disappears spontaneously over a period of several months after giving birth or stopping the oral contraceptives or hormone replacement therapy.
Treatments are often ineffective as it comes back with continued exposure to the sun. Assessment by a dermatologist will help guide treatment. This may include use of a Woods lamp to determine depth of the melasma pigment. Treatments to hasten the fading of the discolored patches include:
- Topical depigmenting agents, such as hydroquinone (HQ) either in over-the-counter (2%) or prescription (4%) strength. HQ is a chemical that inhibits tyrosinase, an enzyme involved in the production of melanin.
- Tretinoin, an acid that increases skin cell (keratinocyte) turnover. This treatment cannot be used during pregnancy.
- Azelaic acid (20%), thought to decrease the activity of melanocytes.
- Tranexamic acid by mouth has shown to provide rapid and sustained lightening in melasma by decreasing melanogenesis in epidermal melanocytes.
- Cysteamine hydrochloride (5%) over-the-counter. Mechanism of action seems to involve inhibition of melanin synthesis pathway
- Flutamide (1%)
- Chemical peels
- Microdermabrasion to dermabrasion (light to deep)
- Galvanic or ultrasound facials with a combination of a topical crème/gel. Either in an aesthetician's office or as a home massager unit.
- Laser but not IPL (IPL can make the melasma darker)
Evidence-based reviews found that the most effective therapy for melasma includes a combination on topical agents.
In all of these treatments the effects are gradual and a strict avoidance of sunlight is required. The use of broad-spectrum sunscreens with physical blockers, such as titanium dioxide and zinc dioxide is preferred over that with only chemical blockers. This is because UV-A, UV-B and visible lights are all capable of stimulating pigment production.
Patients should avoid other precipitants including hormonal triggers.
Cosmetic camouflage can also be used to hide melasma.
See also
- Linea nigra
- Hyperpigmentation in Addison's Disease
- List of cutaneous conditions
References
External links
- DermNet colour/melasma
Source of the article : Wikipedia
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