Dermal melasma အောက်လွှာတင်းတိပ် ထွက်ခြင်း

Melasma is a common brown patches discoloration on the face which is mainly due to overproduction of melanin within the skin. Melasma is common in females (90%) than males (10%), darker skin types and tropical regions. Genetic factor is one of the causing factors in 33-50% of people. It is associated with female hormones (estrogen and progesterone), birth control pills, pregnancy, thyroid disease and UV radiation.

Types of melasma
There are three types of melasma: epidermal, dermal and mixed type based on the depth of pigmentation. Generally, the diagnosis of melasma is made by visual examination, but the wood’s lamp can identify the depth of melanin. According to Oakley, A. (2014), epidermal melasma is a well-defined, dark brown pigmentation which is more obvious under wood’s lamp and easy to treat. Dermal melasma is ill-defined, light brown or bluish patch, which is unchanged colour under wood’s lamp, but difficult to treat. Mixed melasma is combination of bluish and brown patches (mixed pattern) with various degree of treatment outcome. On dermoscopic examination, it is possible to see prominent hyperpigmentation in the pseudo-rete ridges of the skin (Oluwatobi, A. and Elbuluk, N., 2017). Sometimes, skin biopsy is required to distinguish from other hyperpigmented diseases.

The severity of melasma can be measured by using the Melasma Area and Severity Index (MASI). Since there is poor response to treatment in dermal melasma, we need to find out the possible causes and choose the suitable option. Though melasma is not a serious condition, it may cause the patient’s psychosocial and emotional distress.

Management

To manage the melasma, we need to find out all possible factors such as sunlight exposure, hormonal medications and thyroid function test and then, need to decide the type of melasma. To treat dermal type melasma, we have two options: topical medications and systemic medications (Cleverland clinic, 2020). In topical therapy, there are many topical agents such as Hydroquinone, Hydrocortisone, Azelaic acid, Tretinoin, AHA, Methimazole, Cysteamine, Soybean extract, Tranexamic acid. Among them, Hydroquinone is the most commonly used in melasma, but it can cause dermatitis. Other topical agents like Arbutin, Deoxyarbutin, Glutathione, Absorbic acid (vitamin C), Kojic acid or kojic acid dipalmitate, Licorice extract, Mequinol, Resveratrol, Runicol, Zinc sulfate. Oral medications like tranexamic acid, Polypodium leucotomos, and glutathione can be effective in dermal melasma (Oluwatobi, A. and Elbuluk, N., 2017). Chemical peeling, microneedling, radiofrequency, IPL (intense pulsed light) and lasers are other options, but the drawback is post inflammatory hyperpigmentation (PIH). Among laser treatments, non-ablative fractional lasers and Q-switched lasers can be used. Sometimes, camouflage can be used to cover up the hyper pigmented areas.

Oral treatment

Tranexamic acid was the first-line agent in treating dermal melasma according to the findings of previous studies. The positive outcome was usually achieved in many studies when compared to other treatment because they prevent not only tyrosinase activities indirectly but also fibroblastic activation and angiogenesis together with reduced mast cells degranulation. The Polypodium leucotomos extract has the prominent antioxidant action to protect the UV-induced inflammatory response within dermis. That is why it can be assumed as effective agent in the management of dermal melasma. The other antioxidants like GSH and procyanidin revealed some protective roles in prevention of dermal melasma. Apart from the systemic agents, no studies favored the preventive role of chemical peels, laser or laser treatments in the management of dermal melasma except topical agents.

Topical treatment 

Most topical agents in the study were direct or indirect tyrosinase inhibitors and mainly used in the treatment of epidermal or mixed melasma. According to the studies, Kojic acid, arbutin and niacinamide are the more suitable solution than the hydroquinone or TCC because of their efficacy and lesser side effects with the possibility of long-term use. However, most of the studies lack the prominent evidence for dermal melasma. Therefore, it would be too early to draw conclusion from this study and more studies are really needed to be done in the future.

Chemical peels

In the context of melasma, no studies favored the role of chemical peels in the treatment of dermal melasma, though many studies revealed positive outcome of glycolic acid in epidermal melasma. The destructive nature of epidermis, or sometimes dermis will not guarantee to be safe and effective in the pigmented lesions of dermis.

Laser

When comparing the different laser treatment, it can be assumed that Qs Nd:YAG laser is the most useful procedure in many cases of melasma patients. However, this study assumed a potential of replacing their role with picosecond laser in the near future because of the lesser side effects and tissue damage. However, the cost effectiveness of both options were not considered due to some limitations. In this study, the efficacy of Alexandrite laser cannot be identified for dermal melasma, but it seems probable having higher efficacy than the Er:YAG laser. 

Intense pulse light (IPL)

IPL had very little chances of overtaking the role of laser treatment due to their efficacy limited to epidermal melasma and high risk of damage to the surrounding skin, which lead to undesirable hyperpigmentation. The limited role of laser is defined by their variable outcomes and inability to prevent further attack of melasma.

Sunscreen

Tinted sunscreen plays an important role for prevention and treatment of dermal melasma. When choosing the sunscreen, the tinted physical sunscreen with a higher SPF value will prevent not only the UV rays, but also the visible light.

In conclusion, the most effective treatment for dermal melasma was oral medications, followed by topical therapies and laser treatment. Also, the preventive role of tinted sunscreen should not be underestimated in the management of dermal melasma.

Dr. Aye Min Htoo

(Dermatologist)