The effects of a diode laser (810 nm) on pigmented guinea-pig skin

Various types of lasers, such as the Q-switched ruby laser and the Alexandrite laser, cause selective damage to cutaneous pigmented cells and are currently used in the therapy of pigmented lesions. The aim of this study was to evaluate the effects of a diode laser at a wavelength of 810 nm on pigmented guinea-pig skin. The diode laser was supplied by OcuLight Iris Medical Instruments, Inc. and was used to deliver 0.15, 0.2, 0.3, 0.4, 0.5, 1 and 1.5 J/cm² laser beams in micropulses of 100 μs. The study was carried out on albino and black-spotted guinea pigs (GP). After irradiation, punch biopsies were taken and analysed by light and electron microscopy. Albino animals developed just a few signs of cutaneous injury. This mostly consisted of spongiotic disarray, after the highest doses were administered (>1 J/cm²). In the black skin of spotted GPs alterations appeared at 0.15 J/cm² and included melanosome damage and, at doses higher than 0.3 J/cm², also melanocyte damage. These observations demonstrate that the diode laser at 810 nm selectively affects pigmented structures and that the cellular targets of diode laser radiation are the melanosomes. The diode laser specificity for melanin may provide a biological basis for the treatment of pigmented superficial cutaneous lesions. Paper received 15 December 1999; accepted 5 October 2000.     

Pulsed dye laser treatment of benign cutaneous pigmented lesions.

Superficial benign cutaneous pigmented lesions that commonly present to the dermatologists and plastic surgeons have been treated by many conventional modalities such as dermabrasion, depigmenting creams as well as several types of lasers. Many of these treatment modalities lack specificity of injury, which has meant that normally pigmented and even non-pigment containing structures such as collagen as well as the hyperpigmented lesion itself have all been indiscriminately destroyed. This has resulted variously in hypopigmentation, hyperpigmentation, in addition to scar formation in some cases. A coaxial 504 nm laser with a pulse duration of 300 nsec was used to treat fifty two patients with superficial benign cutaneous pigmented lesions. Although the number of treatments required to clear the lesion varied according to the type of lesions being treated, on average, between 2 and 4 treatments were required to completely eradicate the superficial benign cutaneous pigmented lesions using 504 nm pulsed dye laser. The skin at the site successfully cleared of the pigmented lesion remained normal in skin color, texture, markings, and mobility.     

Progress report on extended clinical use of the argon laser for cutaneous lesions

Since 1970 a variety of cutaneous lesions have been successfully treated with the argon laser and the histopathology carefully studied at the Palo Alto Medical Clinic. Patients with port wine hemangiomas, capillary/cavernous hemangiomas, and telangiectasia have achieved successful resolution in some cases, and subtotal blanching in other cases, with a low incidence of scarring or other complications. Recently, decorative tattoos as well as a variety of miscellaneous pigmented or vascular skin lesions, such as seborrheic keratoses, pyogenic granulomas, and senile angiomas, have also been successfully treated with the argon laser. Total clinical experience is updated in this report.     

Treatment of Exogenous Ochronosis With a Q-Switched Alexandrite (755 nm) Laser

Background. Exogenous ochronosis is a cutaneous disorder characterized by blue-black or slate-gray hyperpigmentation resulting from the prolonged use of certain topical agents, most commonly hydroquinones. It is notoriously difficult to treat.
Objective. To report the effectiveness of a quality-switched (QS) 755-nm alexandrite laser in treating hydroquinone-induced exogenous ochronosis.
Methods. Hydroquinone-induced exogenous ochronosis in two patients was treated with a QS alexandrite laser. The first patient received six treatments (average fluence=7.8 J/cm²) at 2-month intervals. The second patient received four treatments (average fluence=6.9 J/cm²) at 4-month intervals. Biopsies of lesional skin were obtained before and after laser treatment for histologic evaluation.
Results. Significant lightening of the pigmented skin areas was achieved in both patients without scarring or textural changes. Decreased dermal pigmentation was observed on histologic examination of treated skin specimens.
Conclusion. The QS alexandrite laser can effectively treat exogenous ochronosis without untoward side effects.     

The square and uniform intensity ruby laser for the treatment of pigmented skin lesions

Summary 285 various pigmented skin lesions from 282 patients were treated over the past 2 years and 10 months using the square and uniform intensity laser equipment. Also, laser effects on 44 skin specimens were studied histologically. The treated clinical lesions included 111 pigmented nevi, 97 nevi spili, 6 Becker's nevi, 10 epidermal nevi, 22 senile freckles, 16 seborrheic keratoses, and 23 other skin lesions. Satisfactory results 6 months or more after the final treatment of 212 of the skin lesions were obtained in 12/96 (12.5%) pigmented nevi; 13/75 (17.3%) nevi spili; 3/5 (60.0%) Becker's nevi; 3/7 (42.9%) epidermal nevi; 9/17 (52.9%) senile freckles; and 9/12 (75.0%) seborrheic keratoses. Judged on the histological examination of pigmented nevi, satisfactory results were obtained in 5 out of 11 superficial compound nevi, 1 out of 32 deep compound nevi, and 2 out of 12 deep intradermal nevi. Assessment methods will be discussed, and ruby laser treatment will be compared to conventional therapy.     

Appearance of New Vemurafenib-associated Melanocytic Nevi on Normal-appearing Skin: Case Series and a Review of Changing or New Pigmented Lesions in Patients with Metastatic Malignant Melanoma After Initiating Treatment with Vemurafenib

Background: Vemurafenib, a selective BRAF inhibitor that has antineoplastic activity in patients with unresectable or metastatic malignant melanoma whose tumor harbors a BRAF V600E mutation, has multiple drug-associated cutaneous adverse effects. Purpose: To provide a detailed and comprehensive review of reported changing or new pigmented lesions in oncology patients who have been treated with vemurafenib. Methods: The new appearance of melanocytic nevi on normal-appearing skin after initiating treatment with vemurafenib is described in two men with metastatic malignant melanoma whose tumors demonstrated a BRAF V600E mutation. Using the PubMed database, an extensive literature search was performed for the following topics: vermurafenib, nevus, nevi, melanoma, pigmented lesion, cutaneous, adverse effect, side effect. The results of the search were used to secure all reports of new or changing pigmented lesions after initiating treatment with vemurafenib. Results: Vemurafenib is associated with both changes in existing pigmented lesions (including involution, alteration of color and size, and progression to melanoma) and the onset of new melanocytic lesions—nevi (in 5 patients) and primary melanomas (in 2 patients). Visual examination, dermoscopic evaluation, and reflectance confocal microscopy have been used to document the changes in existing or new melanocytic lesions subsequent to initiating treatment with vermurafenib. Histopathology analysis has shown these lesions to usually be either dysplastic nevi or new primary melanomas. Conclusion: Vemurafenib-treated patients can develop new pigmented lesions (such as nevi) and/or morphological changes in their existing melanocytic lesions (such as involution, increase in size, or alternation of color). In addition, they can develop new primary malignant melanomas that either occur de novo on normal-appearing skin or develop in pre-existing melanocytic lesions. Therefore, total body skin examination should be considered prior to initiating treatment with vemurafenib. Regularly scheduled follow-up skin examinations are also recommended for patients while they are receiving this drug. In addition, for patients who are being treated with vemurafenib, either dermoscopic or photographic or visual modalities should be used to evaluate new or changing pigmented lesions. Also, biopsy for histopathology should be considered for vemurafenib-treated patients who develop new pigmented lesions or whose existing melanocytic lesions have morphological changes in size or color.Vemurafinib is a selective BRAF inhibitor that was approved by the United States Food and Drug Administration (FDA) on August 17, 2011, as a first-line single agent for the treatment of individuals with unresectable or metastatic malignant melanoma whose tumors demonstrated a BRAF V600E mutation as detected by an FDA-approved test.1-4 Clinical trials have demonstrated improved survival in patients with either previously untreated or treated BRAF V600E mutant metastatic malignant melanoma.5,6 The authors describe two men with metastatic malignant melanoma for which their tumor genotype demonstrated BRAF V600E mutation who experience the new onset of nevi after initiating treatment with vemurafenib and discuss changing or new pigmented lesions in patients with metastatic malignant melanoma after starting this molecularly targeted therapy.     

"Hot" KTP-laser treatment of facial angiofibromata

BACKGROUND AND OBJECTIVE: Treatment of facial angiofibromata (AF) relied largely upon cutaneous resurfacing. While effective, resurfacing affects large areas with attendant risks of dyspigmentation, infection, and scarring. We investigated the pulsed KTP (532 nm) laser energy for its high absorption by melanin and hemoglobin as a photothermal destructive method for treating AF. STUDY DESIGN/MATERIALS AND METHODS: In five patients (Fitzpatrick phototypes II-;VI), AF were treated with the KTP laser (10 ms, 20 J/cm(2), 2 mm beam) using stacked pulses (2-3.3 Hz) or passes. No cooling device was employed. Each pulse evoked puffs of steam and caused progressive flattening of AF. Normal intervening skin was strictly avoided. Patients underwent one to five sessions in which as many as 100 lesions were treated. RESULTS: Individual lesions responded with complete flattening in one or two treatments. While this effect has persisted for 18-;24 months, slow recrudescence is expected. Transient hypopigmentation and hyperpigmentation were localized to treated skin. No scarring, infection, or other adverse events were observed. Patient satisfaction with this method was high due to rapid healing time ( < 10 days), minimal pain, ease of wound care, and efficacy. CONCLUSIONS: "Hot" KTP laser is an effective and safe method of treatment for facial AF. Limiting treatment only to lesional skin allowed rapid healing and very limited adverse effects despite the increased non-specific thermal damage caused by high fluence, long pulse duration, and an absence of superficial tissue cooling.     

Treatment of lupus erythematosus with pulsed dye laser

BACKGROUND AND OBJECTIVES: The treatment of cutaneous lupus erythematosus (CLE) with dye and argon laser has been evaluated in a number of articles in recent years. The improvement of telangiectasias and chronic erythema of the cutaneous lesions was based on the selective photothermolysis ablation of the dilated capillaries and venules. STUDY DESIGN/MATERIALS AND METHODS: We describe the results of the treatment of cutaneous lesions of 14 patients; eight with discoid lupus erythematosus (DLE) and six with systemic lupus erythematosus (SLE). Three patients received a treatment with flashlamp pulsed dye laser (FPDL) (585 nm, 450 microseconds) with fluences in the range from 5 to 7.75 J/cm(2); the other 11 patients were treated with long pulsed dye laser (LPDL) (595 nm, 1.5-10 milliseconds) with fluences in the range from 6 to 13 J/cm(2) depending on the pulse duration. RESULTS: During a median follow-up of 10 months, we observed an average improvement in over 60% of the lesions. A few side effects were observed in all patients: four had transient hyperpigmentation and one patient had light scarring. Three patients had a relapse after more than 1 year; they were then offered conventional treatment. CONCLUSIONS: We confirm that pulsed dye laser is a good alternative treatment for the erythema in active cutaneous lesions of lupus erythematosus (LE).     

532-nanometer green laser beam treatment of superficial varicosities of the lower extremities

Green laser light at 532 nm was utilized in an attempt to thrombose and blanch superficial varicosities of the lower extremity in 14 patients. Selective vascular damage with sparing of overlying skin was the theoretical rationale for use of green light. Seven of the 14 patients achieved satisfactory results (total or near-total obliteration of vessels without scarring) after a 6-month period of observation.     

Q-switched laser treatment of tattoos

In the last decade, Q-switched lasers have expanded the clinician’s ability to treat decorative, cosmetic and traumatic tattoos without scarring. Previous methods of gross tissue removal with resultant scarring have been replaced by the highly selective removal of tattoo pigment with minimal changes in skin texture or pigmentation. This article reviews use of the Q-switched ruby, Q-switched neodymium-yttrium-aluminum-garnet and Q-switched alexandrite lasers in the clinical management of patients with tattoos.     

Treatment of superficial cutaneous vascular lesions: experience with the KTP 532 nm laser

Whilst most facial telangiectasias respond well to short-pulse-duration pulsed dye laser therapy, studies have shown that for the treatment of larger vessels these short-duration pulses are sub-optimal. Long-pulse frequency-doubled neodymium:YAG lasers have been introduced with pulse durations ranging from 1–50 ms and treatment beam diameters of up to 4 mm. We report the results of KTP/532 nm laser treatment for superficial vascular skin lesions. The aim was to determine the efficacy of the KTP/532 nm laser in the treatment of superficial cutaneous vascular lesions at a regional dermatology centre in a 2 year retrospective analysis. Patients were referred from general dermatology clinics to a purpose-built laser facility. A test dose was performed at the initial consultation and thereafter patients were reviewed and treated at 6 week intervals. Outcome was graded into five classifications by the patient and operator independently based on photographic records: clear, marked improvement, partial response, poor response, and no change or worsening. Over the 2 year period, 204 patients with 246 diagnoses were treated [156 female; median age 41 (range 1–74) years; Fitzpatrick skin types I–III]. Equal numbers of spider angioma (102) and facial telangiectasia (102) were treated. Of those patients who completed treatment and follow up, 57/58 (98%) of spider angiomas and 44/49 (90%) of facial telangiectasia markedly improved or cleared. Satisfactory treatment outcomes, with one clearance and two partial responses, occurred in three of five patients with port-wine stain. Few patients experienced adverse effects: two declined further treatment due to pain, and a small area of minimal superficial scarring developed in one case. Two patients developed mild persistent post-inflammatory hyperpigmentation, and one subject experienced an episode of acute facial erythema, swelling and blistering after one treatment. The KTP/532 nm frequency-doubled neodymium:YAG laser is a safe and effective treatment for common superficial cutaneous vascular lesions in patients with Fitzpatrick skin types I–III.     

Treatment of pigmented skin lesions with argon laser irradiation

The article gives an account of material concerning treatment of 60 patients with pigmented lesions of the skin (capillary hemangiomas, pigmented nevus, tattoos) by exposure to argon laser radiation. The optimal regimens and doses of laser radiation for discoloration of pigmented skin lesions are stated. Methodological recommendations for applying three methods fo laser treatment of extensive capillary hemangiomas are suggested. The method used by the authors for treating pigmented skin lesions produced good and satisfactory cosmetic results in 95% of cases.     

Minimizing Scars With Excision and Immediate Laser Resurfacing

The Ultrapulse^® CO ₂ laser has been used extensively for cosmetic resurfacing of the skin. This modality adds the precision and depth control that peels and dermabrasion lack. With the healing model of epithelial migration, precisely coapted wound margins should heal with minimal scarring. I conducted my study with 10 patients with facial lesions and acne scarring grades I to III. Grade I covers mild, very superficial depressions; grade II is defined by moderate scarring; and in grade III, deep scars to the dermis and subcutaneous tissue. Grades II and III were treated with excision and immediate laser resurfacing of the skin with minimally perceptible scars.     

皮肤色素痣不同治疗方法疗效分析比较

目的：比较冷冻、激光及手术治疗皮肤色素痣的疗效及美容效果。方法：皮肤色素痣患者4682例,分为三组：液氮冷冻组600例,用手持式冷冻刀或医用棉签行液氮冷冻治疗;激光组1882例,分别用超脉冲CO2激光和Q开关翠绿宝石激光治疗;手术组2200例,采用切除缝合或切除后邻近皮瓣修复。治疗后对疗效及副作用进行评价。结果：液氮、激光治疗较表浅的色素痣和雀斑样痣疗效较好,对皮内痣及混合痣疗效差且易产生瘢痕;手术切除缝合可治疗各种类型的色素痣,治疗次数少、术后不良反应少并且无明显切口瘢痕。结论：皮肤色素痣治疗应首选手术切除,同时术后应行组织病理学检查。对于较表浅的色素痣和雀斑样痣可选择冷冻和激光治疗,皮内痣和复合痣不宜采用冷冻和激光治疗。     

Cutaneous leishmaniasis: a diagnostic challenge for plastic surgeons

Owing to the relatively low number of patients with cutaneous leishmaniasis seen in plastic surgery clinics, these lesions may easily be confused with other skin diseases and cutaneous malignancies. Seven patients with cutaneous leishmaniasis, who had been misdiagnosed as cutaneous malignancies, were referred to our plastic surgery department. The final diagnoses were made using a Tzanck smear examination and histopathologic examination. Systemic or intralesional meglumine antimonite was successfully used to treat the lesions. Plastic surgeons should be aware that some atypical skin lesions might be a cutaneous leishmaniasis, even if they have a malignant appearance. Surgery may worsen the course of disease, but early medical treatment prevents severe scarring.     

Human mycetoma

BACKGROUND: Mycetoma is a tropical superficial fungal infection endemic in parts of Africa. It affects the foot and leg commonly, but any part of the body may be involved. Mycetoma presents with characteristic discharging sinuses containing fungal granules, a picture that is pathognomonic. However, the disease may present without these characteristic features, thus causing diagnostic difficulty with other chronic granulomatous infections such as tuberculosis or benign skin lesions. METHODS: A review of four male and three female patients aged 28-70 years with mycetoma seen during a six-year period. RESULTS: The duration of the lesion before presentation was between two and six years (median five years). Clinical presentation included pigmented cutaneous nodules, depigmented spots, multiple discharging sinuses, or a fungating mass with bone erosion, involving almost any part of the body (face, trunk, and leg). The range of clinical misdiagnoses included skin tuberculosis, fibroma, amelanotic melanoma, basal-cell carcinoma, and brain tumor. Histologic examination of tissue biopsies showed amorphous aggregates of eosinophilic granules in a background of chronic suppurative inflammation. CONCLUSION: Mycetoma is a disease with sporadic occurrence in our environment. The presentation and clinical course may be confused with those of many skin diseases. Knowledge of mycetoma pathology is important for prompt diagnosis and treatment of this indolent clinical entity.     

Tunable dye laser (577 nm) treatment of port wine stains

Despite steady improvement in the laser treatment of port wine stains (PWS), hypertrophic scarring remains a serious side-effect in approximately 10% of patients. The tunable dye laser (577 nm) has been shown to cause selective vascular destruction in normal and PWS skin. We have treated ten patients using a tunable dye laser (577 nm, 300 mu sec) resulting in clearing of the PWS without any evidence of hypertrophic scarring. Treatment requires no anesthesia or wound care, and there were no postoperative infections.     

Er:YAG Laser for the Treatment of Actinic Keratoses

BACKGROUND: There is no single optimal treatment for multiple facial actinic keratoses. The existing therapies such as topical 5-fluorouracil, chemical peels, cryotherapy, dermabrasion, and CO2 laser resurfacing can produce prolonged recovery time or are often operator dependent. OBJECTIVE: The purpose of this study was to investigate another therapeutic modality which provides a shorter recovery time with uniform results. We performed a prospective pilot study investigating the use of the Er:YAG laser for the treatment of multiple facial actinic keratoses. METHODS: Five patients with multiple facial actinic keratoses were treated with two to three passes of Er:YAG laser. Anesthesia was achieved in all cases by topical application and local infiltration when indicated. All patients were treated with 2.0 J, 5 mm spot size, and a fluence of 10 J/cm2. Clinical and histologic evaluations were performed both pre- and postoperatively. RESULTS: All patients showed a decrease in the total number of clinical actinic keratoses on the face ranging from 86 to 96%. In addition to the reversal of actinic damage in the epidermis, histologic evidence revealed increased fibroplasia and decreased superficial solar elastosis 3 months after the laser resurfacing. Reepithelialization occurred in 5-8 days, and erythema lasted for about 3-6 weeks after the procedure. There was no evidence of scarring or pigmentary changes in any of the patients during the follow-up period. CONCLUSION: Er:YAG laser skin resurfacing is a safe and effective treatment for multiple facial actinic keratoses. Histologic data suggest a new zone of collagen deposition occurs in the superficial papillary dermis. Under our current parameters, Er:YAG laser skin resurfacing has a relatively short recovery period and a low risk of scarring. Unlike the CO2 laser, Er:YAG laser skin resurfacing can be performed with topical anesthesia alone.     

Q-开关Nd:YAG激光治疗外源性皮肤色素性病变124例

目的：观察Q-开关Nd：YAG激光治疗外源性皮肤色素性病变的临床效果。方法：用Q-开关Nd：YAG激光1064nm波长治疗黑色、灰色或蓝色皮肤色素性病变；532nm波长治疗红色色素性病变，共计124例。结果：此方法可明显去除外源性皮肤色素性病变，效果好、无瘢痕产生，但需多次治疗。结论：Q-开关Nd：YAG激光治疗外源性皮肤色素性病变安全有效。     

Successful Removal of Freckles in Asian Skin with a Q-Switched Alexandrite Laser

BACKGROUND.: Although freckles are light-brown macules most frequently observed in individuals with red or blond hair and blue or gray eyes, freckles are common to Asian people, including Koreans. Treatment may be requested on cosmetic grounds. OBJECTIVE.: The objective of this study was to determine the effectiveness of the Q-switched alexandrite laser (wavelength 755 nm; pulse width 100 nsec) in treating the 197 cases of Asian skin with freckles and to observe any side effects such as pigmentary changes or scarring. METHODS.: One hundred ninety-seven patients with freckles were treated with the Q-switched alexandrite laser at 8-week intervals and clinically analyzed. RESULTS.: More than 76% removal of freckles required an average of 1.5 treatment sessions with 7.0 J/cm2. No scarring, long-standing pigmentary changes, or textural changes were seen in laser-irradiated skin. CONCLUSION.: The Q-switched alexandrite laser is a safe and highly effective modality for removing freckles without scarring or permanent pigmentary changes in Asian skin.