Impact of skin hydration on patterns of microthermal injury produced by fractional CO2 laser.

OBJECTIVES: The impact of skin hydration on patterns of thermal injury produced by ablative fractional lasers (AFLs) is insufficiently examined under standardized conditions. Using skin with three different hydration levels, this study assessed the effect of hydration status on microchannel dimensions generated by a fractional CO2 laser. METHODS: A hydration model (hyperhydrated-, dehydrated- and control) was established in ex vivo porcine skin, validated by changes in surface conductance and sample mass. After, samples underwent AFL exposure using a CO2 laser (10,600 nm) at two examined pulse energies (10 and 30 mJ/mb, fixed 10% density, six repetitions per group). Histological assessment of distinct microchannels (n = 60) determined three standardized endpoints in H&E sections: (1) depth of microthermal treatment zones (MTZs), (2) depth of microscopic ablation zones (MAZs), and (3) coagulation zone (CZ) thickness. As a supplemental in vivo assessment, the same laser settings were applied to hyperhydrated- (7-h occlusion) and normohydrated forearm skin (no pretreatment) of a human volunteer. Blinded measurement of MAZ depth (n = 30) was performed using noninvasive optical coherence tomography (OCT). RESULTS: Modest differences in microchannel dimensions were shown between hyperhydrated, dehydrated and control skin at both high and low pulse energy. Compared to controls, hyperhydration led to median reductions in MTZ and MAZ depth ranging from 5% to 8% (control vs. hyperhydrated at 30 mJ/mb; 848 vs. 797 µm (p < 0.003) (MAZ); 928 vs. 856 µm (p < 0.003) (MTZ)), while 14%-16% reductions were shown in dehydrated skin (control vs. dehydrated at 30 mJ/mb; MAZ: 848 vs. 727 µm (p < 0.003); MTZ: 928 vs. 782 µm (p < 0.003)). The impact of skin hydration on CZ thickness was in contrast limited. Corresponding with ex vivo findings, hyperhydration was similarly associated with lower ablative depth in vivo skin. Thus, median MAZ depth in hydrated skin was 10% and 14% lower than in control areas at 10 and 30 mJ/mb pulse energy, respectively (10 mJ: 210 vs. 180 µm (p < 0.001); 30 mJ: 335 vs. 300 µm (p < 0.001)). CONCLUSION: Skin hydration status can exert a minimal impact on patterns of microthermal injury produced by fractional CO2 lasers, although the clinical implication in the context of laser therapy requires further study.

Worldwide expert recommendations for the diagnosis and management of vitiligo: Position statement from the international Vitiligo Task Force-Part 2: Specific treatment recommendations.

BACKGROUND: The treatment of vitiligo can be challenging. Up-to-date agreed consensus recommendations on the use of topical and systemic therapies to facilitate the clinical management of vitiligo are currently lacking. OBJECTIVES: To develop internationally agreed-upon expert-based recommendations for the treatment of vitiligo. METHODS: In this consensus statement, a consortium of 42 international vitiligo experts and four patient representatives participated in different online and live meetings to develop a consensus management strategy for vitiligo. At least two vitiligo experts summarized the evidence for different topics included in the algorithms. A survey was then given to a core group of eight experts to resolve the remaining issues. Subsequently, the recommendations were finalized and validated based on further input from the entire group during two live meetings. RESULTS: The recommendations provided summarize the latest evidence regarding the use of topical therapies (steroids, calcineurin inhibitors and Jak-inhibitors) and systemic therapies, including steroids and other systemic immunomodulating or antioxidant agents. The different modalities of phototherapies (NB-UVB, photochemotherapy, excimer devices and home phototherapy), which are often combined with other therapies, are also summarized. Interventional approaches as well as depigmentation strategies are presented for specific indications. Finally, the status of innovative and targeted therapies under development is discussed. CONCLUSIONS: This international consensus statement culminated in expert-based clinical practice recommendations for the treatment of vitiligo. The development of new therapies is ongoing in vitiligo, and this will likely improve the future management of vitiligo, a disease that still has many unmet needs.

Expert opinion about laser and intense pulsed light (IPL)-induced leukoderma or vitiligo: a cross-sectional survey study.

Vitiligo patients may desire laser hair removal, skin rejuvenation, vascular treatments, and other laser or intense pulsed light (IPL) assisted treatments. However, there is a risk of inducing new depigmented patches (Koebner phenomenon). In absence of guidelines on the safe use of laser or IPL in vitiligo patients, dermatologists tend to be reluctant to administer these treatments. The aim of this survey study was to provide an estimation of the occurrence and related risk factors of laser/IPL-induced leukoderma or vitiligo. A cross-sectional survey study was performed among 15 vitiligo experts from 11 countries, with 14 questions about affected patients, involved laser/IPL treatments and the physicians' approach. In a total of 11,300 vitiligo patients, laser/IPL-induced leukoderma or vitiligo was reported in 30 patients (0.27%). Of these, 12 (40%) patients had a medical history of vitiligo and seven (58%) of these patients had stable (> 12 months) vitiligo before the treatment. Most frequently reported were hair removal procedures and localization of the face and legs. Side effects like blistering, crusting, and erosions occurred in 56.7% of the cases. These vitiligo experts based their advice on the risk of the laser treatment on stability of the vitiligo (43%) and activity signs (50%), and 50% discuss the risks before starting a laser treatment. Relevant activity signs are the Koebner phenomenon (57.1%), confetti-like lesions (57.1%) and hypochromic borders (50%). Laser-induced leukoderma or vitiligo is an uncommon phenomenon. Remarkably, a minority had a medical history of vitiligo of which 58% were stable. Consequently, most cases could not have been prevented by not treating vitiligo patients. However, a majority had laser/IPL-induced skin damage. Therefore, caution is advised with aggressive settings and test-spots prior to the treatment are recommended. This study showed significant variation in the current recommendations and approach of vitiligo experts regarding laser/IPL-induced leukoderma or vitiligo.

Generalized eczematous reaction after fractional carbon dioxide laser therapy for tattoo allergy.

Allergic tattoo reactions form a therapeutically difficult entity. Treatment with conventional quality-switched lasers does not completely remove the allergenic particles and may lead to generalized hypersensitivity reactions. Recently, ablative fractional laser therapy was introduced as a treatment for allergic tattoo removal. We present two cases of allergic reactions to red tattoo ink treated with 10,600-nm fractional CO2 laser. At the end of treatment, almost complete removal of red ink accompanied by a significant reduction of symptoms was observed in the first patient, whereas the second patient developed an acute generalized eczematous reaction after five treatments. These findings confirm that ablative fractional laser therapy is capable of significant removal of tattoo ink in an allergic tattoo reaction. However, it implies a risk of generalized hypersensitivity reactions. To our knowledge, this is the first case of a generalized hypersensitivity reaction following treatment of tattoo allergy with the fractional CO2 laser.

An overview of clinical and experimental treatment modalities for port wine stains.

Port wine stains (PWS) are the most common vascular malformation of the skin, occurring in 0.3% to 0.5% of the population. Noninvasive laser irradiation with flashlamp-pumped pulsed dye lasers (selective photothermolysis) currently comprises the gold standard treatment of PWS; however, the majority of PWS fail to clear completely after selective photothermolysis. In this review, the clinically used PWS treatment modalities (pulsed dye lasers, alexandrite lasers, neodymium:yttrium-aluminum-garnet lasers, and intense pulsed light) and techniques (combination approaches, multiple passes, and epidermal cooling) are discussed. Retrospective analysis of clinical studies published between 1990 and 2011 was performed to determine therapeutic efficacies for each clinically used modality/technique. In addition, factors that have resulted in the high degree of therapeutic recalcitrance are identified, and emerging experimental treatment strategies are addressed, including the use of photodynamic therapy, immunomodulators, angiogenesis inhibitors, hypobaric pressure, and site-specific pharmaco-laser therapy.

An overview of three promising mechanical, optical, and biochemical engineering approaches to improve selective photothermolysis of refractory port wine stains.

During the last three decades, several laser systems, ancillary technologies, and treatment modalities have been developed for the treatment of port wine stains (PWSs). However, approximately half of the PWS patient population responds suboptimally to laser treatment. Consequently, novel treatment modalities and therapeutic techniques/strategies are required to improve PWS treatment efficacy. This overview therefore focuses on three distinct experimental approaches for the optimization of PWS laser treatment. The approaches are addressed from the perspective of mechanical engineering (the use of local hypobaric pressure to induce vasodilation in the laser-irradiated dermal microcirculation), optical engineering (laser-speckle imaging of post-treatment flow in laser-treated PWS skin), and biochemical engineering (light- and heat-activatable liposomal drug delivery systems to enhance the extent of post-irradiation vascular occlusion).

Formation of fibrosis after nonablative and ablative fractional laser therapy.

BACKGROUND: Fractional laser therapy (FLT) has become a widely accepted modality for skin rejuvenation and has also been used in various other skin diseases. OBJECTIVE: To observe long-term histologic effects of nonablative and ablative FLT in the treatment of pigment disorders. METHODS: A randomized controlled observer-blinded study was performed in 18 patients with pigment disorders. Two similar test regions were randomized to receive FLT with intermittent topical bleaching or topical bleaching alone. Patients with ashy dermatosis (AD) and postinflammatory hyperpigmentation (PIH) were treated using nonablative 1,550-nm FLT (15 mJ/microbeam, 14-20% coverage), whereas patients with Becker's nevus (BN) were treated with ablative 10,600-nm FLT (10 mJ/microbeam, 35-45% coverage) for three to five sessions. Biopsies were obtained 3 months after the last treatment. RESULTS: At follow-up, dermal fibrosis was observed in four of eight patients treated using ablative FLT and no patients treated using nonablative FLT (p < .05). CONCLUSIONS: Assuming that the dermal response is comparable in AD, PIH, and BN, at the given settings, ablative FLT may induce fibrosis, whereas treatment with nonablative FLT does not. Whether formation of fibrosis has to be regarded as dermal remodeling or a subtle subclinical form of scarring should be investigated in future research.

Non-ablative 1,550 nm fractional laser therapy versus triple topical therapy for the treatment of melasma: a randomized controlled split-face study.

BACKGROUND: Melasma is a uichronic, often relapsing skin disorder, with poor long-term results from all current therapies. OBJECTIVE: To assess efficacy and safety of non-ablative 1,550 nm fractional laser therapy (FLT) as compared to the gold standard, triple topical therapy (TTT). STUDY DESIGN: Twenty-nine patients with melasma were included in a randomized controlled observer-blinded study with split-face design. Each side of the face was randomly allocated to either 4-5 non-ablative FLT sessions (15 mJ/microbeam, 14-20% coverage) or TTT (hydroquinone 5%, tretinoin 0.05%, triamcinolone acetonide 0.1% cream). TTT was applied once daily for 15 weeks until the last FLT session. After this last treatment, patients were asked to apply TTT twice weekly on both sides of the face during follow-up. Improvement of melasma was assessed by patient's global assessment (PGA), patient's satisfaction, physician's global assessment (PhGA), melanin index, and lightness (L-value) at 3 weeks, and at 3 and 6 months after the last treatment. RESULTS: Mean PGA and satisfaction were significantly lower at the FLT side (P<0.001). PhGA, melanin index, and L-value showed a significant worsening of hyperpigmentation at the FLT side. At the TTT side, no significant change was observed. At 6 months follow-up, most patients preferred TTT. Side effects of FLT were erythema, burning sensation, edema, and pain. Nine patients (31%) developed PIH after two or more laser sessions. Side effects of TTT were erythema, burning sensation, and scaling. CONCLUSIONS: Given the high rate of postinflammatory hyperpigmentation, non-ablative 1,550 nm fractional laser at 15 mJ/microbeam is not recommendable in the treatment of melasma. TTT remains the gold standard treatment.