aRTicle | dermatology |
Physical treatments the use of lasers should be selective and generally only used in those cases in which there is a proven resistance to the most common previously described therapies. In the past, attempts to treat melasma with lasers that targed melanin, such as the Q-switched ruby laser (694 nm), the short-pulsed green dye laser (504–510 nm), the Q-switched neodymium laser (1064 nm), and the argon laser (514 nm), yielded disappointing results; perhaps because these lasers cause an inflammatory reaction in the skin, this tends to lead to a postinflammatory hyperpigmentation. Better results are obtained with er:yag laser resurfacing, and through the combination of pulsed carbon dioxide (Co2 Co2
) laser with Q-switched alexandrite laser because the laser would destroy melanocytes, while the
alexandrite laser would remove the pigment left in the dermis. Intense pulsed light (IPl) is a non-coherent,
broad-spectrum light source that emits a continuous spectrum in the range of 500–1200 nm. With regard to wavelengths, IPl sources can be used with lower cut-off filters to treat superficial pigmentation, such as freckles, and higher cut-off filters for deeper lesions, such as nevus spilus. IPl has been used to treat melanocytic lesions with promising results. the therapeutic efficacy is relatively higher in patients with epidermal-type melasma than those in the mixed type43
. this phenomenon could be
related to the location of the melanin. In epidermal melasma, the melanosomes in the epidermis rapidly migrate to the skin surface and shed off with the microcrusts. In mixed melasma, the melanin-laden macrophages in the dermis are barely damaged44, 45 Zoccali et al have demonstrated excellent results with the use of IPl in melasma in their recent study46
. . they
treated 38 patients (with Fitzpatrick Skin types III–IV) with between three and five IPl sessions at intervals of 40–45 days, and used a 550 nm handpiece because it has a greater selectivity for melanin and reaches the deeper epidermis. two pulses of 5–10 ms with a 10–20 ms delay between the pulses and the fluence (energy density: J/cm2
energy levels of 12–14 J/cm2
) was modulated with regard to the anatomic area. are used to treat the cheek
and zygoma, 10–12 J/cm2 (7–8 J/cm2
for the forehead, and lower levels ) are reserved for the perioral region and neck.
results were excellent in 18 patients (47.37%), good in 11 (28.95%), moderate in five (13.16%), and poor in four cases (10.52%), in which a recurrence of hyperpigmented areas occurred within 2–4 months 46
. Collateral effects are minimal and include a burning
pain during treatment and a short-lasting erythema. Possible complications include transitory hyperpigmentation
changes, persistent
hypopigmentation, and, rarely, scarring. a recent 10-week, split-face study by goldman et al47
evaluated the safety and efficacy of triple combination therapy when used sequentially with IPl in patients with moderate to severe melasma versus an inactive control cream associated with IPl at weeks 2 and 6. the maSI score was significantly less with triple combination (tC) therapy cream and IPl than with inactive cream and IPl at weeks 6 (P = 0.007) and 10 (P = 0.002), and the treatment was well tolerated, although cutaneous irritation was greater with IPl plus triple combination cream than with IPl plus inactive cream (P < 0.25 for all assessments). In the authors’ opinion, IPl can be considered a valid
therapeutic option, particularly in patients who do not respond to conventional topical agents; however, only temporary and transient results can be achieved, with the new appearance of hyperpigmentation lesions after a number of weeks or months (Figures 1 and 2). Fractional resurfacing (Fr) is a novel concept of skin
rejuvenation that has the potential to treat a variety of epidermal and dermal conditions48
. It produces a unique
thermal damage pattern. In contrast to ablative skin resurfacing and non-ablative skin resurfacing, which achieve homogenous thermal damage at particular depth, Fr creates microscopic thermal wounds, referred to as the microthermal treatment zone (mtZ)49
. Fr
specifically spares tissue surrounding each mtZ, allowing for rapid re-epithelialisation and epidermal repair owing to the small size of the wounds and short migratory paths for keratinocytes. examination of the histology of mtZs shows homogenisation of dermal collagen and the formation of microscopic epidermal
Figure 3 A patient treated with intense pulsed light therapy, before (A) and after (B) the treatment
intense
pulsed light (iPl) is a non-coherent, broad-spectrum light source that emits a
continuous
spectrum in the range of 500– 1200 nm.
24 ❚ July 2011 |
prime-journal.com
IMAGES GHERSETICH
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