Melasma is one of the most commonly-acquired hypermelanosis of skin exposed to the sun. Treatments including hypopigmenting agents and chemical peels have been used, but at present no pharmacologic agent has been universally recognised as effective for the treatment of melasma. Recently, the Q-switched Nd:YAG laser has been proposed. This evaluation confirms how, by minimising side-effects, treatment time and costs, the Q-switched Nd:YAG laser can be effective and safe for lightening cutaneous hyperpigmentation. The biological role of cutaneous blood vessels in the pathogenesis of melasma is an interesting topic and opens new therapeutic perspectives. The authors recently performed a prospective study for evaluating the effects of pulsed dye laser (PDL) therapy. After a multispectral study for evaluating haemoglobin and melanin components, the authors are now using this vascular laser with low-fluence and have obtained some improvements. It would be tempting to think that the action of PDL on the vascularisation might have played an important role in preventing relapse. By targeting vascularisation, and at least some part of the elastosis in the melasma lesions, it might be possible to decrease the stimulation of melanocytes and thus reduce the incidence of relapse.
Hyperpigmentary disorders, particularly melasma and other forms of primary and secondary hyperpigmentation, can cause significant social and emotional stress in patients. Management is often challenging owing to the limited number of successful treatment options currently available. Different therapeutic methods have been used that can be divided into topical and cosmetic treatments (with depigmenting agents such as hydroquinone, methimazole, pidobenzone, tretinoin, arbutin, azelaic acid, ellagic acid, mequinol, ascorbic acid, and resveratrol) alone or in combination with chemical peels or physical treatments.
Laser devices have revolutionised the treatment of many dermatological conditions, including pigmentary disorders. They have been widely used with variable levels of success for the treatment of pigmented conditions such as Becker’s nevus, café au lait macules, nevus of Ota, nevocellular nevus, lentigines, tattoos, melasma, and post-inflammatory hyperpigmentation (PIH). Although many pigmentary disorders have shown good results with laser treatment, the efficacy and safety of lasers for melasma is still controversial, with most authors citing chemical peels as the most effective treatment option.
Laser treatment of pigmented lesions is based on the theory of selective photothermolysis, which entails a specific wavelength of energy delivered in a shorter period of time than the thermal relaxation time (τr) of the target chromophore, meaning that the energy is restricted to the target, thus causing less damage to the surrounding tissue1–2. A selective window for targeting melanin lies between 630 nm and 1100 nm, where there is good skin penetration and preferential absorption of melanin over oxyhaemoglobin3. Absorption of the melanin decreases as the wavelength increases, but a longer wavelength allows for deeper skin penetration. Shorter wavelengths (< 600 nm) damage pigmented cells with lower energy fluencies, while longer wavelengths (> 600 nm) penetrate deeper, but need more energy to cause melanocytic damage4.
The ideal aim of laser therapy is to reduce the appearance of chromatic alterations, as well as reduce the risk of disfiguring scars and permanent dyschromia. Laser systems for hyperpigmentation can be divided into:
- ■ Surgical lasers
- ■ QS Nd:YAG (Q-switched neodymium-doped yttrium aluminum garnet; 532 nm), QS ruby (694 nm), QS alexandrite (755 nm), QS Nd:YAG (1064 nm)
- ■ Intense pulsed light (IPL; 500–1200 nm).