Histological evaluation of dermal tissue remodeling with the 1444‐nm neodymium:yttrium–aluminum–garnet laser in in vivo model

Laser lipolysis has a skin tightening effect by heating the deep dermis, in addition to the removal of fat tissues. The 1444‐nm neodymium:yttrium–aluminum–garnet (Nd:YAG) laser has been expected to be more effective and safe for laser lipolysis, due to higher affinity to fat and water, than 1064‐nm and 1320‐nm wavelengths. The purpose of this study was to evaluate the skin tightening effect of the 1444‐nm Nd:YAG laser through in vivo guinea pig models. The 1444‐nm Nd:YAG laser was used to irradiate shaved dorsal skin of the guinea pigs and compared with controls (no power, only tunneling). Immediately, 1 week, 1 month and 3 months after laser administration, full‐thickness skins were harvested and to evaluate dermal thickness, collagen organization, fibroblast proliferation, and intensity of elastic fibers and mucopolysaccharides, using hematoxylin–eosin, Masson‐trichrome, Verhoeff's stain and Alcian blue stain. Dermal thickness showed an increase with time in all groups. In collagen organization, fibroblast proliferation, and intensity of elastic fibers and mucopolysaccharides, the treatment groups were higher than those of the control group, overall. Our study showed that the 1444‐nm Nd:YAG laser appeared to be effective for the skin tightening effect in in vivo guinea pig models. The 1444‐nm Nd:YAG laser can be used for skin tightening, as well as reduction of fat tissues.     

Induction of melasma by 1064‐nm Q‐switched neodymium:yttrium–aluminum–garnet laser therapy for acquired bilateral nevus of Ota‐like macules (Hori nevus): A study on related factors in the Chinese population

Laser treatment has emerged as a common treatment modality for acquired bilateral nevus of Ota‐like macules (ABNOM). To identify the ratio of melasma induction and exacerbation before and after laser therapy for ABNOM and to observe the risk factors related to the induction and exacerbation of melasma by laser therapy, we analyzed related factors of 1268 adult Chinese patients who underwent 1064‐nm Q‐switched neodymium:yttrium–aluminum–garnet (Nd:YAG) laser (QNYL) treatment using case series and case–control studies. Overall, 24.0% of the ABNOM patients had mixed melasma. Among the ABNOM patients without melasma, after laser therapy the development of melasma was more frequently noted in patients older than 35 years (P < 0.0001), as well in patients whose ABNOM was less than 10 cm² (P = 0.027), ABNOM were light (similar to yellow‐brown) in color (P = 0.021) and skin types were closer to type IV (P < 0.0001). New melasma lesions also appeared most frequently in the zygomatic region (P < 0.0001). Among the ABNOM patients with melasma, 89.5% experienced worsening of their melasma, irrespective of their related factors above. We concluded that the risk of inducing melasma is great after 1064‐nm QNYL treatment in ABNOM patients, and particularly in the patients with both ABNOM and melasma. ABNOM patients should be treated as early as possible and before the age of 35 years.     

Treatment of atrophic facial acne scars with fractional Er:Yag laser

Background: Acne scars are often a permanent disfiguring sequel of acne vulgaris. Although many treatment modalities are available, they are often non satisfactory for all patients. Objective: To determine the effectiveness and safety of fractional 1540 nm erbium_glass laser treatment of facial acne scars in Iraqi patients. Patients and methods: Twenty one patients were enrolled in this prospective clinical study. Three sessions of the 1540 nm erbium glass laser were applied at 2-week intervals. The patients were assessed at 1, 3, and 6 months after the last session. The effect of treatment was assessed by objective (Sharquie scoring system for grading acne scarring and visual analog scale) and subjective (patient satisfaction) methods. Results: Two patients were defaulted. Eleven patients (57.9%) showed improvement from moderate to mild grade, and no grade changes were detected in eight patients (42.1%). The mean score of the visual analog scale prior to treatment was 8.61 ± 0.86 and decreased to 6.15 ± 1.28 (P = 0.037). Ten patients were satisfied to varying degrees. No significant side effects were noted. Conclusion: Non-ablative fractional 1540 nm erbium glass laser is an effective and safe method to treat acne scars and represent good alternative for patients who cannot use the ablative methods because of its longer downtime.     

A cross‐sectional,multi‐center study on treatment of facial acne scars with low‐energy double‐pass 1450‐nm diode laser

Acne scars are the ultimate outcome of acne vulgaris, a prevalent skin disorder affecting the pilo‐sebaceous unit. Laser resurfacing has been demonstrated to be an efficient therapy option for acne scars. Hence, we adopted this concept and conducted a study to evaluate the safety and efficacy of low‐energy double‐pass 1450‐nm diode laser on acne scars. This study was conducted on 48 patients with acne scars, treated at 4‐week interval with low‐energy double‐pass 1450‐nm diode laser. Patients were evaluated clinically and with photographs, at day 0, first month and third month post the final treatment and during follow‐up visit. Five treatment sessions were completed by all patients. Approximately, 79.2% of patients showed around 30% improvement. At the end of third month follow‐up, 92.9% of the patients demonstrated >30% improvement. Vesicle formation was observed in two cases, with no post‐inflammatory hyperpigmentation and transient hyperpigmentation was observed in one case, which vanished within 2 months. Our study showed that 1450‐nm diode laser treatment was efficient and well endured in facial acne scars when used with double‐pass at low‐energy.     

Non‐ablative 1550‐nm erbium‐glass and ablative 10 600‐nm carbon dioxide fractional lasers for acne scars: a randomized split‐face study with blinded response evaluation

Background Non‐ablative 1550‐nm erbium‐doped fractional photothermolysis systems (FPS) and 10 600‐nm carbon dioxide fractional laser systems (CO₂ FS) have been effectively used to treat scars. Objective We compared the efficacy and safety of single‐session treatments of FPS and CO₂ FS for acne scars through a randomized, split‐face, evaluator‐blinded study. Methods Eight patients with acne scars were enrolled in this study. Half of each subject’s face was treated with FPS and the other half was treated with CO₂ FS. We used a quartile grading scale for evaluations. Results At 3 months after the treatment, the mean grade of improvement based on clinical assessment was 2.0 ± 0.5 for FPS and 2.5 ± 0.8 for CO₂ FS. On each side treated by FPS and CO₂ FS, the mean duration of post‐therapy crusting and scaling was 2.3 and 7.4 days respectively and that of post‐therapy erythema was 7.5 and 11.5 days respectively. The mean VAS pain score was 3.9 ± 2.0 with the FPS and 7.0 ± 2.0 with the CO₂ FS. Conclusion We demonstrated the efficacy and safety of single‐session acne scar treatment using FPS and CO₂ FS in East Asian patients. We believe that our study could be used as an essential reference when choosing laser modalities for scar treatment.     

Intense pulsed light vs. pulsed‐dye laser in the treatment of facial acne: a randomized split‐face trial

Background Various laser and light therapy have been increasingly used for the treatment of acne vulgaris. Patients and methods Twenty patients with facial acne were treated using intense pulsed light (IPL) on one side of the face and pulsed dye laser (PDL) on the other to compare the efficacy and safety of IPL and PDL. Treatment was performed 4 times at 2‐week intervals. Treatment effectiveness was determined using lesion counts, acne severity, patient subjective self‐assessments of improvement, and histopathological examinations, which included immunohistochemical staining for transforming growth factor‐β (TGF‐β). Results Numbers of total acne lesions decreased following both treatments. For inflammatory lesions such as papules, pustules and nodules, IPL‐treated sides showed an earlier and more profound improvement than PDL‐treated sides. However, at 8 weeks after the 4th treatment, a rebound aggravation of acne was observed on IPL‐treated sides. On the contrary, PDL produced gradual improvements during the treatment sessions and these improvements lasted 8 weeks after the 4th treatment. Non‐inflammatory lesions as open and closed comedones also showed improvement following both treatments and PDL‐treated sides showed better improvement as the study proceeded. Histopathological examinations showed amelioration in inflammatory reactions and an increase in TGF‐β expression after both treatments, which were more prominent for PDL‐treated sides. Conclusion Both PDL and IPL were found to treat acne effectively, but PDL showed a more sustained effect. TGF‐β might play a key role in the resolution of inflammatory acne lesions.