Formation of fibrosis after nonablative and ablative fractional laser therapy

A Retrospective Analysis of the Efficacy and Safety of Q-Switched and Picosecond Lasers for Treating Becker’s Nevus

Background. Becker’s nevus (BN) severely affects a patient’s appearance and can lead to depression, especially when it involves the face or neck. Currently, there is no effective treatment. Laser therapy has become popular, but its efficacy has not been confirmed. We evaluated the efficacy and safety of lasers in treating BN. Methods. This retrospective study involved 49 patients exposed to different laser treatments who completed at least one treatment session and follow-up. Results. The patients treated with the 755-nm alexandrite picosecond laser and Q-switched 694-nm ruby laser gained relatively good results: 3.07 ± 1.09 and 2.87 ± 1.14 on the five-point scale and 3.47 ± 0.73 and 3.40 ± 0.85 on the GAIS, respectively. However, the results of the 755-nm alexandrite picosecond laser with a diffractive focus lens array and the fractionated 1064-nm neodymium-doped: yttrium aluminum garnet picosecond laser were poor. Furthermore, there were marked differences between the number of treatment sessions and treatment effects, both for the five-point grading score for pigment clearance (F = 15.246, $p<0.001$ ) and GAIS (F = 15.469, $p<0.001$ ). Concerning different lasers and efficacy, there were no marked differences between the five-point grading scale and the GAIS ( $p>0.05$ ). Conclusions. Although the efficacy of various lasers for BN is not satisfactory and there are no marked differences between picosecond and Q-switched lasers, they can help in selecting an appropriate laser for slight-to -moderate pigment removal. The 755-nm alexandrite picosecond laser is a new option, whereas nonablative fractional picosecond lasers for BN are not recommended. Increasing the number of treatment sessions can improve the curative effect slightly.

An update on Becker's nevus: pathogenesis and treatment

Becker's nevus (BN) manifests as a hyperpigmented, sometimes hypertrichotic plaque/patch over the chest and shoulder, and it is in the category of benign cutaneous hamartomas. BN has elongation and fusion of the rete ridge, keratotic plugging, sebaceous hyperplasia, smooth muscle hyperplasia, and hyperpigmentation of the basal/suprabasal layer histologically. This article highlights all issues involved in pathogenesis and treatment options of BN. According to current research, postzygotic ACTB mutations induce BN and Becker's nevus syndrome (BNS). Although several therapy strategies were utilized to treat the pigmentary and hypertrichotic aspects of BN, no definitive standard treatment was identified to far, and further research is needed to better educate BN care. This article is protected by copyright. All rights reserved.

Lasers for Becker's nevus

Becker's nevus is a common pigmented dermatosis, usually featured by ipsilateral pigmented patch with hypertrichosis. Becker's nevus is often treated with various types of lasers although other regimens are available. However, clinical outcomes appear inconsistent among studies. To summarize the clinical outcomes of Becker's nevus treated with lasers via literature review. A variety of lasers had been used alone or in combination to treat Becker's nevus. Laser wavelengths used for Becker's nevus ranged from 504 to 10,600 nm, while the number of treatment varied from 1 to 12 sessions. The clinical outcomes were mixed although combination of lasers with different wavelengths appeared to achieve a better efficacy. Adverse effects were usually mild to moderate erythema. While lasers are relatively safe, their efficacy for Becker's nevus is moderate. It seems that combination therapy could improve the outcome. However, trials in larger group of patients are required to validate the efficacy of each type of lasers for Becker's nevus.

Erythema dyschromicum perstans: A case report and systematic review of histologic presentation and treatment

Objective

Erythema dyschromicum perstans (EDP) can be difficult to diagnose and treat; therefore, we reviewed the literature to assess whether histology can be used to differentiate lichen planus pigmentosus (LPP) from EDP and determine which treatments are the most effective for EDP. We also present a case of a patient who was treated successfully with narrow-band ultraviolet B (NB-UVB).

Methods

A systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses was conducted up to July 2017 using four databases.

Results

Histologic analyses from the literature reveal a significant percentage of melanophages, lymphocytic infiltrates, and basal vacuolar degeneration in EDP, and a significant histologic overlap with LPP. The review of the literature on treatment outcomes showed that NB-UVB and tacrolimus were effective with minimal side effects. Clofazimine was effective, but demonstrated significant-to-intolerable side effects. Griseofulvin, isotretinoin, and dapsone provided unsatisfactory results as lesions recurred after discontinuation. Lasers were largely ineffective and may cause postinflammatory hyperpigmentation and fibrosis.

Conclusion

A diagnosis of EDP should not be based on histologic findings alone. Clinical history, morphology, and distribution should be used to differentiate EDP and LPP. NB-UVB and tacrolimus are promising treatments for EDP with minimal side effects. This is the first report to our knowledge of sustained resolution of EDP after treatment with NB-UVB at long-term follow-up of 4 years. Larger studies are needed to confirm these findings.

Fractional Erbium laser in the treatment of photoaging: randomized comparative, clinical and histopathological study of ablative (2940nm) vs. non-ablative (1540nm) methods after 3 months

BACKGROUND

Fractional non-ablative lasers keep the epidermis intact, while fractional ablative lasers remove it, making them theoretically more effective.

OBJECTIVES

To evaluate the clinical and histological alterations induced by fractional photothermolysis for treating photoaging, comparing the possible equivalence of multiple sessions of 1540nm Erbium, to one session of 2940nm Erbium.

METHODS

Eighteen patients (mean age 55.9) completed the treatment with three sessions of 1540nm fractional Erbium laser on one side of the face (50 mJ/mB, 15ms, 2 passes), and one session of 2940nm on the other side (5mJ/mB, 0.25ms, 2 passes). Biopsies were performed before and 3 months after treatment. Clinical, histological and morphometric evaluations were carried out.

RESULTS

All patients presented clinical improvement with no statistically significant difference (p> 0.05) between the treated sides. Histopathology revealed a new organization of collagen and elastic fibers, accompanied by edema, which was more evident with the 2940nm laser. This finding was confirmed by morphometry, which showed a decrease in collagen density for both treatments, with a statistical significance for the 2940nm laser (p > 0.001).

CONCLUSIONS

Three 1540nm sessions were clinically equivalent to one 2940nm session. The edema probably contributed to the positive results after three months, togheter with the new collagen and elastic fibers organization. The greater edema after the 2940nm session indicates that dermal remodeling takes longer than with 1540nm. It is possible that this histological superiority relates to a more prolonged effect, but a cohort longer than three months is needed to confirm that supposition.

Histologic comparison of microscopic treatment zones induced by fractional lasers and radiofrequency

INTRODUCTION

Fractional photothermolysis induces microscopic, localized thermal injury in the skin surrounded by undamaged viable tissue in order to promote wound healing.

OBJECTIVE

This study evaluated acute histologic changes following each single pass of various fractional lasers and radiofrequency (RF).

METHODS

Three male domestic swine were used. We used fractional Erbium:glass (Er:glass), Erbium:yttrium-aluminum-garnet (Er:YAG), CO2 lasers, and fractional ablative microplasma RF. We analyzed features and average values of the diameter, depth, and vertical sectional areas treated with each kind of laser and RF.

RESULTS

The microscopic treatment zone (MTZ) of fractional Er:glass resulted in separation of dermoepidermal junction with no ablative zone. Fractional Er:YAG provided the most superficial and broad MTZ with little thermal collateral damage. Fractional CO2 resulted in a narrow and deep "cone"-like MTZ. Fractional RF resulted in a superficial and broad "crater"-like MTZ.

CONCLUSIONS

This study provides the first comparison of MTZs induced by various fractional lasers and RF. These data provide basic information on proper laser and RF options. We think that these findings could be a good reference for information about fractional laser-assisted drug delivery.