INTRODUCTION AND DEFINITION
Laser treatment of vascular lesions was first developed in 1960s, and the risks of scarring and texture changes were very common in the early days. In 1983, the concept of selective photothermolysis revolutionized the use of laser for the treatment of vascular lesions. Since then, pulsed dye laser (PDL) has become the gold standard in the treatment of port wine stains (PWSs). However, for technical reasons in the past, no PDL had been developed with a pulse duration longer than 1 millisecond (ms) until the late 1990s. However, complications, especially dyspigmentation such as hypopigmentation and hyperpigmentation, were common, especially in dark-skinned patients. To minimize complications caused by higher fluence in dark-skinned patients, epidermal protection by skin cooling was developed. Newer-generation PDLs provide extended pulse durations, adequate skin cooling, and higher power, leading to enhanced clinical efficacy and lower risk of complication, especially in dark-skinned patients.
PWSs are congenital, hypervascular malformations with a dark pinkish appearance that may evolve into nodular and purple lesions later in life. For nearly two decades, PDL was the treatment of choice for PWSs. However, clearance rates vary widely and many lesions cannot be completely cleared with laser treatment. Furthermore, redarkening has been reported among patients treated with PDL 10 years after treatment.1 Improved efficacy in PWS treatment is expected by using variable wavelengths, variable pulse durations, and higher energy fluences with selective skin cooling, and techniques such as pulse stacking.
The use of PDL for the treatment of hemangioma was reported to be associated with a greater risk of complications, including pigmentary disturbance and texture change.2 However, the fluence used was too high, and at that stage, skin cooling was not developed. More recently, extended pulsed PDL with skin cooling was found to be more suitable in the treatment hemangiomas.3
In contrast to PWSs, facial telangiectasia responds well to 532-nm neodymium:yttrium-aluminum-garnet (Nd:YAG) laser, PDL, and intense pulsed light (IPL) source. Short-pulsed PDL (1.5 ms or less) is effective but purpura formation is very common, leading to unacceptable duration of downtime. The 532-nm or 1064-nm Nd:YAG, extended pulse PDL and IPL are recommended because of the lack of resulting purpura.
LITERATURE REVIEW/EVIDENCE-BASED SUMMARY
In the late 1980s, a 577-nm PDL was developed and Tan et al.4,5 reported an in vivo study on albino pig skin that demonstrated the depth of penetration could be increased from 0.5 to 1.2 mm without affecting vascular selectivity. Verkruysse et al.6 showed this effect by calculating the maximum depth of vascular injury versus wavelength for different amounts of blood in the dermis and for different vessel diameters. Their findings revealed that 585-nm wavelength penetrates deeper into tissue than 577-nm ...