What is melasma?
Melasma is a tan-coloured patchy skin discolouration that often occurs in females. It may affect the forehead, cheeks, nose and chin. It is more prominent in person with darker skin pigmentation and its visual appearance can be a source of distress.
How does melasma arise?
Melanocytes are pigment-producing cells that reside in the skin. They produce melanin which, when transferred to the dermis and epidermis, confers the skin colour to the individual. When there is an over-stimulation of melanocytes it results in irregular pigment deposition, also known as melasma. Some factors that cause over-stimulation include:
- Genetic predisposition – Individuals with Fitzpatrick type III or greater skin (Orientals, Hispanics and Africans) are more likely to develop melasma than those with lighter skin tones.
- Ultraviolet light exposure – This stimulates melanocyte activity and can cause formation of melasma and post-treatment recurrence.
- Hormonal changes – For example during pregnancy, menopause and thyroid disease.
How does melasma manifest?
Melasma manifests as dark, irregular, well-demarcated macules or patches in the face. They develop gradually and are visually distressing due to the contrast of pigmentation between affected and normal skin. Melasma may be distributed in the following locations:
- Centrofacial – Across the forehead, between the eyebrows, the nose, central cheeks, upper lip skin and chin.
- Malar – In the cheek prominence (cheekbones) and the area just in front of the ears.
- Mandibular – Along the border of the lower jaw.
What are the different types of melasma?
Melasma is classified according to its depth which in turn, determines the optimal treatment mode. It can be divided into 2 types:
- Epidermal melasma –This results from increased melanin deposition in the superficial suprabasal layer of the epidermis. Such melasma often manifests as dark brown pigmentation.
- Dermal melasma – This results from excess melanin deposition in the dermal skin layer, which is partially taken up by the macrophages (immune cells). Such melasma often manifests as faint brown spots.
How is melasma treated?
1. Sunblock
It is often said that prevention is the best cure. Diligent and frequent use of topically applied sunscreens (SPF factor 30 and above), especially in individuals who enjoy outdoor activities, excludes penetration of harmful UV-B and UV-C rays into the skin. This minimizes melanocyte stimulation and is key in preventing melasma formation and its recurrence after successful treatment.
2. Oral supplements
While not a treatment for melasma by itself, supplements containing plant-based carotenoids have been shown to be useful when taken in combination with other proven treatments.
3. Chemical peels
Chemical peels contain alpha hydroxy acids, beta hydroxy acids or retinoic acids that stimulate the basal layer of epidermis and cause the peeling of its melanin-containing superficial layers. These peels are often administered in the clinic.
4. Oral medication
Oral tranexamic acid may be used for prevention of melanin production and melasma treatment. It is a novel form of treatment that has been backed by a good body of professional-level peer-reviewed evidence, and shown to be effective in treating both epidermal and dermal melasma. An initial 2 to 3 month course of tranexamic acid is usually prescribed, with re-assessment done at a later date to determine if further treatment is required.
5. Topical medication
The most effective treatment of melasma is the use of combination topical agents containing hydroquinone, tretinoin and a steroid. This form of treatment is effective for both epidermal and dermal melasma. Individuals may initially experience mild skin irritation when treatment commences, but this often resolves with long-term use. Topical medication should be used for a minimum of 2 to 3 months before doing an interval assessment for further improvement.
6. Lasers
Various laser and intense pulsed light therapies may be used for the treatment of melasma. Lasers utilize a focused beam of light, which is selectively more absorbed by skin that contains higher concentrations of melanin. This is converted to heat energy causing melanocyte rupture and death. The melanin is gradually absorbed by macrophages (immune cells) leading to clearance of pigment. Lasers are typically better at treating deeper-lying dermal pigments, and also require committed post-procedural sun protection since the remaining melanocytes can still become stimulated and cause recurrence of melasma.
