Improvements in laser technology over the past decades have allowed for expedited lesion clearing, even for adult patients with PWS. Despite decades of improvement, laser therapy for the treatment of PWS remains a major challenge. For many clinicians, the pulsed dye laser (PDL) is considered as the treatment of choice for PWSs. Almost all PWSs lighten after a series of PDL exploiting wavelengths, ranging from 585 to 600 nm; however, blebbed PWS cannot be completely removed due to limited penetration depth. Different strategies, including excision, electrocautery, repetitive PDL treatments, pulse stacking with PDL, intense pulsed light platforms, and Nd:YAG 1,064 nm have been used for the treatment of resistant PWS4,5
. A long-pulsed Nd:YAG laser penetrates deeply into the skin, and it can be effective in the treatment of vascular targets, such as nodular lesions in PWS and reticular leg veins, and provides cosmetically acceptable results6,7
Selective epidermal cooling, which was studied by Gilchrest et al.8
, was introduced in an effort to preserve the epidermis during the laser treatment of a dermal targets. Dynamic cooling devices, such as cold air (forced air convection), cryogen spray, and contact cooling (sapphire window), have generally allowed for use of higher fluencies in the vascular laser systems. Cooling, as well as a reduction of fluence, prevents adverse effects, such as pigmentary changes and scar formations, and also decreases pain during the treatment, and increases therapeutic outcome.
We have treated most blebs in PWSs using a 1,064 nm long pulsed Nd:YAG laser with contact cooling device. The laser penetrates more deeply into the tissue than visible light, therefore enabling a more deeper heat delivery into these relatively large vascular structures. In addition, it has a contact cooling system that is suitable for epidermal protection, contact compression capacity for control of blood flow to the treated area, and delicate cooling time control on demand. Furthermore, because absorption of melanin, at the 1,064 wavelength is relatively low, it is also suitable for patients with darker skin types, like Asians, whose epidermal melanin, present at higher concentrations, can act as a competing target chromophore for laser light. In this study, a 1,064 nm long pulsed Nd:YAG laser with fluence of 95 J/cm2 to 170 J/cm2, 20 ms to 30 ms pulse duration, 5 mm to 6 mm spot size, and dynamic cooling 30 to 40/20 was used every 8 weeks, illustrating an excellent response with treatment. Compared with the similar cases, which reported in other countries, there's no big difference in the parameter. In foreign countries, however, they mostly conducted a study with the sample of white people; therefore, when we consider that the target of this study are all non-Caucasians, we can see an excellent result, setting up a similar parameter. Also, it's quite remarkable that there are no side effects, such as hyperpigmentation and atrophic scar. Viewed in this light, a 1,064 nm long-pulsed Nd:YAG laser provide a effective treatment for the PWS in most skin types.
PWS typically consists of blood vessels with a diameter between 10 and 50 µm. Very few are >100 µm and most are <20 µm9
. Non-responding PWS probably consist of vessels that are too small or too large. Very small vessels might contain too little oxyhemoglobin to permit sufficient absorption and consequent heating of the vessel wall. In very large vessels, there might not be sufficient energy to heat the whole target10
. In addition, in the study from Yang et al.11
, minimum purpuric dose (MPD) for long pulsed Nd:YAG laser varies widely among different PWS, and MPD values were lower in darker PWS. Based on the facts, laser setting, such as fluence and spot size were carefully determined, according to bulky malformation, the level of maturity, and MPD, and were used with 30 ms pulse duration based on our experience.
Laser therapy of PWS at younger ages is more effective than the treatment in adults, based on the premise that these lesions are relatively immature, and consists of superficial and smaller vessels12
. Important morphological factors include depth of vessels, with superficially located vessels confirmed as a favorable factor13
. The size and location of PWS are also important prognostic factors. A lesions on the head and neck, showing a better response than those at the other sites, and even among those confined to the face, the peripheral face, in particular, the central forehead, confers a better prognosis than the centrofacial areas (V2 distribution)14
. Broader lesions (more than 20 cm2
) tend to require additional laser treatments, compared with narrow lesions, with clearing tending to start from the periphery of lesions. These prognostic factors, determining therapeutic response, may allow for better appreciation of the heterogeneity of PWS, and eventually lead to a more targeted treatment.
PWS are commonly found on the face and neck, and, as such, may have serious psychological consequences. PWS also do not involute over time and may become hypertrophied in adulthood, resulting in an increased disfigurement. For these reasons, early intervention is needed. In blebbed PWS that are resistant to other treatment, our protocol - a 1,064 nm long pulsed Nd:YAG laser with contact cooling device on blebs, followed by PDL on the surrounding flat lesions - may be an efficacious alternative modality of choice for the treatment of blebbed PWS.