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Melasma is an acquired condition characterized by hyperpigmented patches, traditionally located on the face. What the classic definition fails to mention is its chronic relapsing nature and its associated therapeutic dilemma.
There are also four types of melasma based on the location of the melanosomes in the skin, and, hence, described by their woods light pattern. They are: epidermal (accentuated by Woods light), dermal (not accentuated by Woods light), mixed and indeterminate.
Cosmetics, heat exposure, phototoxic drugs and anti-seizure medications have also been implicated in this disease.
Melasma associated with an inciting factor, such as oral contraceptives, may resolve once this inciting factor is removed. In many cases, however, this is not the case, and the pigmentation persists.
Therapeutic options for melasma have classically centered on resolving the hyperpigmentation. These have included topical retinoids, hydroquinone, kojic acid and glycolic acid, to name a few.
More recent attention has been focused on prevention of melanosome transfer with agents including soy and niacinamide. Sun protection is an essential component of any therapeutic regimen when treating patients with melasma.
Though readily available, topical therapies often fail to resolve the hyperpigmentation, which relapses when therapy is discontinued.
The search for alternative forms of treatment has led to a recent focus on laser and light devices.
Melasma is certainly more than merely a disorder of hyperpigmentation. In many cases, there is a vascular component to the lesions that generally gets left untreated. The focus of melasma treatment has been predominantly on the pigmentary aspect of the disease, essentially ignoring the other factors.
Lasers may end up playing a role in the therapy of the vascular components of melasma, as this component is nearly impossible to treat with topical agents.
Role of lasers
Do lasers play a role in the treatment of melasma? There are many reports of the use of lasers for melasma, yet no well-controlled, randomized, blinded trials. There are even approvals for treatment of melasma with lasers. However, the answer to this question is definitely still up for debate.
Lasers were first described as a therapy for melasma in 1993. Early laser choices used those wavelengths highly absorbed by melanin. There have been many case reports of successful treatment with these light devices.
The Q-switched lasers have all been tried on melasma, including in combination with other lasers. The majority of reports have shown very high rates of postinflammatory hyperpigmentation (PIH); in some studies, as high as 100 percent.
That being said, many of the cases of PIH were amenable to topical bleaching agents and glycolic acid peels, resulting in an overall improvement of the melasma.
In these reports, it is difficult to ascertain whether the improvement is actually a result of the laser, or of the peels.
Either way, most would agree that the treatment of melasma with traditional Q-switched lasers, including the ruby, alexandrite or the Nd:YAG is risky.