Melasma is a type of hyperpigmentation also known as ‘chloasma’ and ‘pregnancy mask’. It is a common condition of skin in adults that appears in the form of dark brown or greyish colour pigmentation patches, which mainly targets facial skin. The name melasma is derived from the Greek word ‘melas’, which means black. Melasma occurs most commonly in women, especially pregnant women and people who live in warmer and sunnier climates.
It is a skin disorder characterised by dark skin patches distributed consistently on areas of the body that are primarily exposed to the sun. It is predominantly present in people who have the Fitzpatrick skin type IV-VI,which includes Hispanics, Africans, Asians and American Africans, and causes severe psychological, emotional and social distress.
Etiology and pathogenesis
Although there are numerous contributing factors that play their role in the pathogenesis, the exact cause and the etiology of the condition is yet to be understood.
However, the most common factors that contribute to the development of melisma, include sun exposure, pregnancy, genetics, intake of oral contraceptives, thyroid diseases and some drugs, such as anti-epileptics. The main cause of excessive skin pigmentation is an increased the number of melanocytes and excessive melanin production.The vascular component has also been considered to play a role in the development of melasma.
Clinical and Histological classification of melasma
There are three identified with melisma that have been identified, including:
Melasma has histologically been classified in three distinctive patterns, according to the primary pigmentation accumulation locations, including:
Available Treatment options
There is a range of treatment options available that range from topical applicators to photo protections, lasers,chemical skin peels and others.
It has been observed that a combination of 2 or 3 treatments produces better results than administering a single pigmentation treatment, butdespite this, the melasma treatment remains a challenge because only mild to moderate improvements are achievedin the majority of patients.
Treating melasma in dark-skinned patients
A Fitzpatrick Skin type scale is used to determine the type of skin. In this rating scale, the darker skin tone falls between type IV to Type VI. This type of skin provides better protection against photodamage, but is vulnerable to disorders of pigmentation, such as melasma.
This type of skin has a higher tendency for Post Inflammatory Hyperpigmentation(PIH). This is a type of pigmentation that results from an injury to the skin or is by a skin inflammation, such as photodermatitis, and is most common in darker-skinned people. Itis a limiting factor when pigmentation treatment procedures, like chemical skin peels and lasers, are performed, andit is therefore of the utmost importance to prevent and manage post inflammatory hyperpigmentation following melasma treatment, including chemical skin peels.
Chemical skin peels suitable for treating melasma
Chemical skin peeling treatment involves the application of a chemical on the skin that induces a controlled damage to some parts of the epidermis or the entire epidermis along, with or without damage to the dermis, causing skin exfoliation and the superficial lesions removal. This process is followed by the regeneration of new epidermis and dermis tissues.
Chemical skin peel treatment is a popular option for treating melasma. The treatment generates a controlled chemical burn to the skin that results in the elimination of unwanted melanin. Chemical peels have proved to be an effective treatment for melasma, both as a stand-alone treatment, as well as in combination with topical treatment.
Types of chemical peels for treating melasma in darker skin
Though there are an extensive variety of chemical peels available, the choice is limited when it comes to the treatment of Fitzpatrick type IV to VI patients, because the deeper chemical peels are not appropriate for use on dark-skinned patients as the risks of developing prolonged pigmentation are high. Even the use of medium depth peel should be done with caution.
Melasma Area and Severity Index (MASI) is a scoring system that is used for assessing the severity of the disease and for a treatment response measurement of melasma.
The most common type of alpha hydroxy peel used for treating melasma is glycolic acid (GA). Generally, 30%-70% of GA solution is used for chemical peel treatment. After conducting a test peel, GA peel is performed at an interval of 2-3 weeks for 3-5 minutes. The peel is neutralised with water or with 1% solution of bicarbonate. Studies have supported its effectiveness in treating melasma with a significant reduction in the MASI scoring.
Lactic acid has similar effects as GA peel, but surprisingly it has not been used frequently for melasma treatment.
In recent years, pyruvic acid has gained significant attention for treating various skin conditions.
Pyruvic acid peel possesses a range of properties, including:
In a recent study, an innovative, non-erythematogenic pyruvic acid formulation was used to treat sun damage, superficial scarring and melasma. The study’s results showed that the peel was effective in all the three skin conditions, without any burning to the skin during or after the peel sessions. However, the studies about the use of pyruvic acid peel are limited to the Fitzpatrick skin type II-IV, so it still remains unanswered whether it works well on ethnic skin or not.
Salicylic acid falls into the category of acids that have traditionally been used for treating acne, melasma and PIH. The commonly used concentration of salicylic acid is 20%-30%.
It is a unique combination of AHA and BHA that has not been tried widely yet.
These properties, when combined together in the form of a skin peel, make it an effective skin peeling combination, particularly for ethnic skin. This combination works really well for numerous skin conditions, including acne, pigmentation, acne scarring and melasma. Although there is no clinically published data available for melasma,the salicylic and mandelic combo peel has proved to be much more effective compared to the GA peels for active acne and post-acne hyperpigmentationand with fewer side effects.
Trichloroacetic peel is more frequently used for lighter skin and is less used on darker skin because of the higher risks of scarring, as well as post-peel dyschromias. This peel, when used in a low concentration of 10%-35%, is preferable, as it only reaches the upper papillary dermis. So these peels are unsuitable for treating dermal melasma and its mixed forms on dark-skinned patients.
The TCA peel may prove to be effective, like GA peels, for treating pigment dyschromias but caution should be taken while using these on the darker skin tones due to the higher prevalence of side effects. It can cause hyper or hypopigmentation.
This skin peel uses a combination of salicylic acid, lactic acid, and resorcinol mixed in ethanol. It has been used widely as a superficial peeling agent for all types of skin.
A recentnew development in Jessner’s peel uses a combination the medium depth peels along with other peeling agents, such as GA and TCA peel.
The working oftretinoin peels is considered to be same as that of topical tretinoin applications.
Despite the popularity of traditional skin peeling agents, researchers have continued to explore the newer peeling agents for treating numerous pigmentary dyschromias, including melasma.
One chemical agent that deserves mentioning in this regard is phytic acid peel.
III. Cocktail Skin Peels
This is a unique and innovative example of cocktail skin peels. It is a perfect combo of potent skin peeling agents with skin rejuvenating ingredients, which include TCA, salicylic acid, lactic acid, combined with numerous skin brighteners, as well as antioxidants such as glutathione, mandelic and azelic acid, as well as fruit extracts,among others. The P2R peel possesses powerful ways of treating multiple skin conditions, including pigmentation and sun damage.
The role of priming agents in skin peeling
As has already been mentioned, the primary drawback of using chemical peels for treating melasma in dark skin is post inflammatory hyperpigmentation (PIH), which may occur during or after the treatment sessions. There are various suggestions for addressing this problem, but priming or preparing skin for the treatment is the most useful measure. Thisdoes not just help to decrease PIH, but also enhances the effects of the skin peeling ingredients.
Prevention of relapse
Another issue that arises while treating melasma in dark-skinned patients is the high vulnerability of relapse or reappearance. This particularly occurs with chemical peels because they work by temporarily removing cutaneous melanin, without having any effect on the melanogenesis process or melanocytes. So it requires the rational approach to treatment of using multiple chemical peel sessions (generally 5-6)at an interval of 2-4 weeks, combined with additional therapy for maintenance with chemical skin peel or by using a bleaching agent like hydroquinone, Kojic acid, topical vitamin C serum, tretinoin, which helps to further suppress melanin production.
Chemical skin peeling has evolved into an innovative and unique skin rejuvenation system. This evolution started with traditional peeling agents, such as AHAs, BHAs and TCA, and then progressed to the cocktail of skin peels like Jessner’s peel, which have remained popular for a long period of time. In their terms of effectiveness and safety, traditional GA peels have proved to be the best ones. Lactic acid peels, which are relatively less expensive, showed almost the same results as that of GA, but still need further research. Due to phytic acid peel’s unique properties, it may replace conventional AHAs, while the use of TCA peel in dark-skinned individuals still needs caution, as there are the risks of pigmentation dyschromias.
The trends of peeling are currently changing and the innovative cocktail peels which combine both skin brightening and rejuvenating ingredients are being effectively used for tackling pigmentation and signs of ageing, along with numerous other skin problems, such as acne, clogged pores, skin tone and texture, scarring, etc. They also help to stimulate new cell turnover.
The results of the skin peel depends on the type of peeling agent, including its concentration, frequency and how long it is applied. It is particularly important to provide advice to dark-skinned patientsabout photoprotection, priming agents and the importance of maintenance peels.