Melasma is a common, acquired disorder of hyperpigmentation that causes brown patches on the cheeks, forehead, upper lip and jawline and has a significant
impact on quality of life. Exposure to UV radiation & visible light, familial predisposition, pregnancy and exogenous hormones e.g. the contraceptive
pill can all contribute. Unfortunately, the clinical course of melasma is often protracted and it frequently returns after discontinuation of treatment
or with increased sun exposure.
These are the findings of a 2019 review of medical treatment for melasma published in The American Journal of Clinical Dermatology:
1. The topical depigmenting agent hydroquinone (HQ) is the most extensively studied treatment for melasma. Despite a theoretical risk of adverse effects, multiples studies have demonstrated its excellent safety profile. Triple combination therapy (HQ+ retinoid cream+ weak topical steroid) continues to be the most effective treatment for melasma. Retinoid creams without HQ need to be used longterm for clinical improvement so may form part of a maintenance regime following triple combination therapy.
2. The use of sunscreen with SPF≥30 is mandatory and recently the use of iron oxide-containing sunscreen to provide additional protection from visible light has been advocated.
3. Other depigmenting agents such as topical tranexamic acid (TXA) have not shown higher efficacy than HQ. However, microneedling using TXA has shown promising initial results & microneedling may be a valuable tool for assisting drug delivery to the skin in lieu of laser therapy or chemical peels, which can induce post inflammatory hyperpigmentation (PIH).
4. Azelaic acid and vitamin C have been shown to decrease skin pigmentation and can be used as alternatives when HQ is not an option.
5. Chemical peels, laser and light devices do not show consistent results. Glycolic and salicylic acid peels were not found to be more effective than HQ. Other peels, such as TCA and Jessner, may be a promising alternative in recalcitrant melasma, but larger, controlled studies are needed. A major problem with chemical peels is the risk of post inflammatory hyperpigmentation. Therefore, peels should be considered second-line treatment only and must be used with extreme caution in skin of colour.
Laser- and light-based devices have yielded mixed results. IPL can improve melasma, however relapse rates are high without additional use of HQ. Nd:Yag carries the risk of mottled hypopigmentation. PDL laser is the only treatment that shows a decrease in the relapse of melasma, mainly through targeting the vascular component. Laser and light-based devices should be considered as a third-line treatment for melasma, and should be used judiciously in skin of colour.
6. Finally, oral tranexamic acid has been shown to be a safe and effective treatment for resistant moderate to severe melasma, but carries the risk of deep venous thrombosis due to its antifbrinolytic properties, thus patients should be carefully screened for risk factors of thromboembolic disease.
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