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Use of a Picosecond Alexandrite Laser for Treating Acquired Bilateral Nevus of Ota-Like Macules in Chinese Patients
摘要： Background and Objectives: Acquired bilateral nevus of Ota‐like macules (ABNOM) is common among the Chinese population. There have been few studies on the use of a picosecond alexandrite laser for the treatment of ABNOMs. The goal of this study was to evaluate the efficacy and safety of a 755 nm picosecond alexandrite laser for the treatment of ABNOMs. Study Design/Materials and Methods: A total of 225 subjects diagnosed with ABNOMs were included in this retrospective study. A 755 nm picosecond alexandrite laser system was used to treat all subjects. The safety and effectiveness of the laser were determined using a clinical photo assessment. The correlating factors of the patients, including the age, Fitzpatrick skin type, lesion location, lesion color, treatment procedures, melasma, and outcomes, were analyzed. Results: The patients underwent one to four treatment sessions with clinical clearance (>90%) rates of 8.89%, 30.99%, 56.65%, and 60.00%, respectively. A higher number of sessions was positively associated with a better treatment response. The hyperpigmentation incidence rate was 22.67%, and one case of hypopigmentation was observed. Conclusion: Our results suggest that a picosecond alexandrite laser is an effective and safe approach for treating ABNOMs in Chinese patients.
关键词： acquired bilateral nevus of Ota‐like macules (ABNOM),picosecond alexandrite laser,treatment effect,post‐inflammatory hypopigmentation
更新于2025-09-19 17:13:59
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Comparison of a picosecond alexandrite laser versus a Q-switched alexandrite laser for the treatment of nevus of Ota: A randomized, split-lesion, controlled trial
摘要： Background: Novel picosecond lasers have been available for various pigmentary disorders. However, there are limited data directly comparing picosecond lasers and Q-switched lasers for treatment of nevus of Ota. Objective: To compare the efficacy and safety of a picosecond alexandrite laser (PSAL) compared with a Q-switched alexandrite laser (QSAL) for the treatment of nevus of Ota. Methods: Each lesion of the 56 participants enrolled was split into two parts and randomly assigned to either PASL or QSAL treatment arm. Each lesion was treated up to 6 sessions at a 12-week interval. The efficacy and safety were determined based on blinded visual evaluation and self-report at each follow-up visit. Results: PSAL arm achieved a significantly better clearance (4.53 vs 4.0) with fewer sessions (5.26 vs 5.87) and less severe pain (5.61 vs 6.40). Patients were more satisfied with PSAL than QSAL (4.5 vs 4.0). Occurrences of post inflammatory hyperpigmentation (26% vs 34%) and hypopigmentation (21% vs 47%) were also lower in PSAL than QSAL arm. Limitations: Lack of objective assessments and outcome measures. Conclusions: PSAL demonstrated better clinical results and fewer adverse events than QSAL for the treatment of nevus of Ota.
关键词： photomechanical effect,post-inflammatory hypopigmentation,Q-switched alexandrite laser,nevus of Ota,picosecond alexandrite laser,split-lesion
更新于2025-09-12 10:27:22
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Electron Microscopy of Argyria Treated With Picosecond Alexandrite Laser
摘要： Argyria (from the Greek word for silver, argyros) is the bluish gray discoloration of tissue caused by exposure to silver or its salts, often because of alternative medicine treatment or occasionally through occupational exposure. Since the 1990s, colloidal silver has been available in pharmacy-supplied dietary supplements and homeopathic remedies for the treatment of various diseases, including cancer, immunodeficiency, chronic fatigue, tuberculosis, and other infections, without any substantiating evidence. Long-term consumption of silver products can lead to chronic argyria, with silver deposition in organs, including the skin, liver, spleen, kidneys, and central and peripheral nervous system. Generalized argyria can occur when silver compounds are ingested, applied topically, or inhaled. Argyria can also be localized to certain sites of the skin or eyes if creams or eye drops are used or can be found on the ear lobes when silver earrings are worn. Silver deposits may localize in the eccrine glands of the skin, as well as in the papillary dermis and pilosebaceous follicles. The silver is in the form of silver sulfide and appears to be more abundant in the sun-exposed skin. Argyria has a well-defined toxicity, and discoloration is permanent. Recently, Q-switched nanosecond laser and picosecond alexandrite laser (PicoSure, Cynosure) have been used to treat argyria. Both the Q-switched nanosecond laser and the picosecond alexandrite laser use the principle of selective photothermolysis and have been used in a number of applications, including tattoo removal and pigmentation removal. Pulses of light energy is delivered to the skin and causes fragmentation of ink particles, allowing for phagocytosis and removal of the pigment by macrophages. It is speculated that laser treatment of argyria causes fragmentation of silver deposits in the skin, similar to the mechanisms of tattoo removal. We present a case report of the successful treatment of argyria with picosecond alexandrite laser, as demonstrated by clinical photographs, histopathology, and electron microscopy. This case provides evidence that picosecond laser causes the fragmentation of silver particles in argyria without phagocytosis in the immediate post-treatment phase.
关键词： picosecond alexandrite laser,silver particles,argyria,laser treatment,electron microscopy
更新于2025-09-12 10:27:22