A retrospective study of 1064-nm Q-switched Nd:YAG laser therapy for acquired bilateral nevus of Ota-like macules

BACKGROUND

The therapeutic efficacy of laser treatments for acquired bilateral nevus of Ota-like macules (ABNOM) varies among studies, and few studies have evaluated the factors affecting therapeutic effects.

AIMS

To evaluate the efficacy and safety of 1064-nm Q-switched Nd:YAG laser (QSNYL) therapy for ABNOM and to identify the factors influencing the outcome.

METHODS

A total of 110 patients with ABNOM were retrospectively evaluated and received two-to-nine treatment sessions. The effects of different factors on the therapeutic effect were analyzed on the basis of the number of treatments, age at first treatment, skin type, lesion color, affected area, number of lesion sites, and presence of concomitant melasma.

RESULTS

The curative effect was positively correlated with the treatment time and negatively correlated with the increasing age at first treatment (p < 0.05). The curative effect was better in patients with skin type III than those with type IV ( p < 0.05) and in patients with a lesion area of less than 10 cm2 than those with a larger affected area (p < 0.05). Additionally, the treatment effect was poorer in patients with concomitant melasma (p < 0.05). The treatment effect was not significantly correlated with the lesion color or number of affected sites (p > 0.05). Eleven patients (10%) developed postinflammatory hyperpigmentation (PIH).

CONCLUSIONS

Early and repeated QSNYL therapy achieved satisfactory results for ABNOM. The risk of PIH after laser treatment is highest among patients with older age, darker lesion color, and darker skin color. For patients with ABNOM with concurrent melasma, low-energy laser therapy is recommended to reduce the risk of melasma aggravation.

Efficacy and safety of Q-switched lasers for the treatment of naevus of Ota in children: a retrospective analysis

To identify factors influencing the efficacy of Q-switched laser in the treatment of naevus of Ota in children and to compare the efficacy, safety, and recurrence rate between 1064 nm Q-switched Nd:YAG laser (QSNL) and 755 nm Q-switched alexandrite laser (QSAL). We retrospectively analysed 160 children with naevus of Ota who completed QSAL or QSNL laser treatment at our centre. Age at initial treatment (P = 0.004), colour of lesions (P = 0.025), and number of treatments (P = 0.002) were related to efficacy. Compared with patients aged 0-11 months at initial treatment, patients who started treatment at 1-3 years (OR adj = 0.47), 4-8 years (OR adj = 0.20), and 9-12 years (OR adj = 0.27) had inferior efficacy. The efficacy of brown-violet (OR adj = 2.67) and blue-violet lesions (OR adj = 2.51) was better than that of brown lesions. Moreover, patients who received 3-4 (OR adj = 2.83) or 5-6 (OR adj = 7.35) treatment sessions showed a better response than those who received 1-2 sessions. Additionally, as the age at initial treatment increased, the rate of complications increased from 2.0 to 14.3%, while the recurrence rate decreased from 8.2 to 0%. In addition, the complication rate increased with an increase in the number of treatments. There were no significant differences in clinical efficacy (P = 0.94), risk of complications (P = 0.752), or recurrence (P = 0.834) between QSAL and QSNL for treating naevus of Ota in children. QSAL and QSNL are equally effective for children's naevus of Ota, with low complications and recurrence rates. Younger age at initial treatment and a greater number of treatments are beneficial for efficacy, whereas brown lesions are a negative factor.

Prospective comparison study of a 550 picosecond 755 nm laser vs a 50 ns 755 nm laser in the treatment of nevus of Ota

Since the introduction of selective photothermolysis, Q-switched nanosecond lasers have been used for the treatment of dermal pigmented lesions. Over the past several years, picosecond lasers have been introduced to the cosmetic community. We recently performed a study comparing a 550 picosecond 755 nm laser versus a 50 ns 755 nm laser, with the purpose of evaluating the clinical efficacy and complications of each laser when treating nevus of Ota. Ten Asian patients with nevus of Ota were enrolled in the study. Each lesion was split into 2 parts, and patients were treated with a 755 nm picosecond laser (PSL) and a 755 nm nanosecond laser (NSL). The clinical endpoint for fluence choice was immediate whitening (PSL: 2.33 ~ 3.36 J/cm2, NSL: 5.5 ~ 7 J/cm2) of the treated area. The pulse duration was fixed at 550 picoseconds (PSL) and 50 ns (NSL). The spot size of each laser was 2.5-3 mm. Laser treatments were performed until excellent clinical improvement was observed. Patients were examined 1 week after the first treatment, at each follow-up visit, and 6 months after the last laser treatment. The average number of treatment sessions to achieve excellent clinical improvement was 4.2 treatments using PSL and 5.4 treatments using NSL. One case of hyperpigmentation and one case of hypopigmentation were observed in the NSL treatment group. There were no complications in the PSL treatment group. The 755 nm 550 picosecond laser is significantly more effective than the 755 nm 50 ns laser in the treatment of nevus of Ota. The PSL treatment group also had minimum side effects.

Aiming to personalized laser therapy for nevus of Ota: melanin distribution dependent parameter optimization

Aiming to the personalized laser therapy of nevus of Ota (NO), a local thermal non-equilibrium model was employed to optimize laser wavelength, pulse duration, and energy density under different melanin depth and volume fraction. According to our simulation, the optimal pulse duration is between 15 and 150 ns to limit heat transfer inside the hyperplastic melanin, and 50 ns is recommended to decrease the energy absorption by normal melanin in epidermis. Correlations of the minimum and the maximum energy densities are proposed with respect to melanin depth and volume fraction for the 755-nm and 1064-nm lasers. For the same NO type, the therapy window of the 755-nm laser is larger than that of 1064-nm. For NO with shallow depth or low volume fraction, the 755-nm laser is recommended to make the treatment more stable owing to its lager therapy window. For deeper depth or higher volume fraction, the 1064-nm laser is recommended to avoid thermal damage of epidermis. Through comparison with clinical data, the optimized laser parameters are proved practicable since high cure rate can be achieved when energy density falls into the range of predicted therapy window. With developing of non-invasive measurement technology of melanin content and distribution, personalized treatment of NO maybe possible in the near future.

Efficacy and safety of picosecond 755-nm alexandrite laser for treatment of nevus of Ota in Taiwanese children: A retrospective study

OBJECTIVES

To evaluate the efficacy and safety of picosecond 755-nm alexandrite laser in the treatment of nevus of Ota in children.

MATERIALS AND METHODS

A retrospective study was conducted by reviewing medical charts and photographs of 86 Taiwanese children with various types of nevus of Ota between January 2017 and September 2020. Picosecond 755-nm alexandrite laser therapy was used to treat pigmentary lesions. Percent clearance of lesions during treatment and the treatment time required to achieve 95%-100% clearance were determined.

RESULTS

According to Tanino's classification or Peking University Medical College Hospital (PUMCH) classification of nevus of Ota, most patients belonged to Tanino's Type II (32%) and Type III (38%) or PUMCH Type IIb (33%) and Type IIIb (26%), which indicated that the nevus was mainly distributed in the forehead, upper and lower eyelid, zygomatic, cheek, and temple regions. After treatment with picosecond 755-nm alexandrite laser, 96.5% of the patients achieved 95%-100% clearance with an average of 4.3 treatment sessions. The earlier onset of lesions (before 5 months of age) and the darker Fitzpatrick skin types (type IV vs. type III) significantly increased the number of treatments required to achieve clear response, while sex, age at first treatment, Tanino's classification of nevus, and color of nevus had no significant effect. Posttreatment hypopigmentation or hyperpigmentation was transient and resolved within 6 months. No serious response of the skin was evident.

CONCLUSION

Picosecond 755-nm alexandrite laser treatment of nevus of Ota in children was safe and effective. The treatment was well-tolerated, and only a few transient, minor side effects occurred.

Efficacy and safety of 755 nm Q-switched Alexandrite Laser for Hori's nevus: a retrospective analysis of 482 Chinese women

To evaluate the efficacy and safety of 755 nm Q-Switched alexandrite laser for Hori's nevus in a large cohort of Chinese women. We retrospectively analyzed the efficacy and safety of 755 nm Q-Switched alexandrite laser for Hori's nevus. Reduction in pigment was evaluated using a 4-score method. A total of 482 patients, aged 16 to 52 years, were included in this analysis. Patients were treated with 755 nm Q-Switched alexandrite laser at fluence levels of 5-8 J/cm² for 2-4 treatment sessions. Following the treatments, 53% of patients showed over 75% reductions in pigment while 50-75% reductions in pigment were observed in 28% of patients. The rest displayed less than 50% improvements. Efficacy was positively correlated with the number of treatment sessions (p < 0.0001). Adverse reactions were temporary, mild erythema, and edema. A small portion of patients (15%) had hyperpigmentation, which disappeared within 2-6 months. 755 nm Q-Switched alexandrite laser is safe and has moderate benefits for Hori's nevus. Because its efficacy is positively correlated with the number of treatment sessions, increase in treatment sessions possibly could achieve a better outcome.

Clinical use of the Q-switched Nd:YAG laser for the treatment of acquired bilateral nevus of Ota-like macules (ABNOMs) in Koreans

BACKGROUND

There are still insufficient clinical reports about quality-switched Nd:YAG laser (QSNYL) in the treatment of acquired bilateral nevus of Otalike macules (ABNOMs) in Asians.

OBJECTIVE

To analyze the efficacy and side-effect profiles of QSNYL treatment of ABNOMs in Korean skin.

METHODS

A prospective study was designed to follow 10 Korean patients with ABNOMs through laser treatment until maximal eradication of the lesions had been achieved.

RESULTS

Five patients (50%) with ABNOMs were treated with excellent or good results. The more treatments a patient underwent, the greater the possibility of improvement. There were no cases of persistent skin textural change or persistent erythema.

CONCLUSION

The clinical data support QSNYL being a beneficial alternative tool for treating ABNOMs in brown skin. This is, to the best of the authors' knowledge, the first report about laser treatment of ABNOMs using QSNNL.

Effect of Cold Air Cooling on the Incidence of Postinflammatory Hyperpigmentation After Q-Switched Nd:YAG Laser Treatment of Acquired Bilateral Nevus of Ota–like Macules

OBJECTIVE

To investigate the effect of cold air cooling on the incidence of postinflammatory hyperpigmentation (PIH) after laser treatment in Asian patients.

DESIGN

Randomized, controlled, split-face study.

SETTING

Skin laser center of a university hospital.

PATIENTS

Twenty-three Thai women with acquired bilateral nevus of Ota-like macules.

INTERVENTIONS

Patients were treated using a 1064-nm Q-switched Nd:YAG laser at an average fluence of 7.0 J/cm(2) using a 3-mm spot size. The same laser fluence was used on both sides of the face in individual patients. One randomly selected face side of each patient was cooled using a cold air cooling device during and 30 seconds before and after laser irradiation, and the other side was irradiated without cooling.

MAIN OUTCOME MEASURES

Occurrence of PIH was objectively evaluated by measuring the melanin index using a spectrometer, and it was subjectively assessed by 2 nontreating physicians before treatment and once weekly for 4 weeks.

RESULTS

Of the 21 patients who completed the study, 13 (62%) and 5 (24%) developed PIH on the cooled and uncooled sides, respectively. One patient (5%) had PIH on both the cooled and uncooled sides, and 2 (10%) did not experience PIH. The cooled sides were significantly more likely to become hyperpigmented after laser irradiation than the uncooled sides (relative risk, 2.6; 95% confidence interval, 1.13-6.00; P = .03). The clinical evaluation corresponded to the spectrometer reading.

CONCLUSION

Epidermal cooling with cold air is associated with an increased risk of PIH after Q-switched Nd:YAG laser treatment.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00287001.

Analysis of 602 Chinese Cases of Nevus of Ota and the Treatment Results Treated by Q-Switched Alexandrite Laser

BACKGROUND

Nevus of Ota is a congenital or acquired pigmentary disorder of the skin and mucous membranes, which are areas innervated by the first and second branches of the trigeminal nerve. Nevus of Ota is very common in Asia. Nevus of Ota was effectively treated with Q-switched alexandrite (755 nm) laser, but no detailed report existed on many Chinese cases treated with Q-switched alexandrite laser.

OBJECTIVE

The objective was to gauge clinical and treatment data and material statistics for 602 cases of nevus of Ota and analyze its pathogenic mechanism and therapeutic results.

METHODS

A total of 602 cases of clinical data on nevus of Ota were collected by means of clinical registration, photo verification, and telephone inquiry or correspondence.

CONCLUSIONS

There are some differences in sex, age, and local regions in nevus of Ota. Nevus of Ota can combine with other diseases. The treatment of Nevus of Ota by a Q-switched alexandrite laser is safe and effective. Additional treatment will achieve good results. The results correlate to the eyelids and Tanino's classification.

Treatment of 153 Japanese patients with Q-switched alexandrite laser

We have recently used Q-switched alexandrite laser for the treatment of various kinds of pigmented skin lesions. We retrospectively compared therapeutic outcomes of 153 Japanese patients who consulted our department. This approach was not very efficient for nevus spilus/café-au-lait spots, which seemed laser-resistant, especially when the pigmentation had appeared after 1 year of age, was treated after 5 years of age, was located on the face, was oval with a smooth border, and the patient was male. This approach was equally effective for senile lentigo, nevus of Ota, and Mongolian spots, but less effective for acquired bilateral nevus of Ota-like macules. Some patients with sacral Mongolian spots or those with light-colored, senile lentigo developed severe post-inflammatory hyperpigmentation after treatment. As a whole, good therapeutic outcome was achieved after multiple treatment sessions. However, the use of other lasers or other treatment modalities should be considered to treat nevus spilus/café-au-lait spots.

Treatment of acquired bilateral nevus of ota-like macules (Hori's nevus) with a combination of the 532 nm Q-Switched Nd:YAG laser followed by the 1,064 nm Q-switched Nd:YAG is more effective: prospective study

BACKGROUND

Acquired bilateral nevus of Ota-like macules (Hori's nevus) is a common dyschromatosis among Asian women. Q-switched lasers have been used successfully as a treatment modality.

OBJECTIVE

The purpose of this study was to compare the efficacy of using the Q-switched 532 nm neodymium:yttrium-aluminum-garnet (Nd:YAG) laser followed by the 1,064 nm laser versus the Q-switched 1,064 nm Nd:YAG laser alone in the treatment of Hori's nevus.

METHODS

This is a prospective left-right comparative study. Ten women with bilateral Hori's nevus were recruited and treated with a combination of the Q-switched 532 and 1,064 nm Nd:YAG lasers on the right cheek and the Q-switched 1,064 nm Nd:YAG laser alone on the left cheek. Only one laser treatment session was performed. The degree of pigmentation was objectively recorded with a mexameter. Subjective assessment was made by both patients and two blinded, nontreating dermatologists.

RESULTS

At 6 months, there was a statistically significant difference (p = .009) of 35.10 points using objective mexameter measurements between the two sides, favoring the side treated with a combination of 532 and 1,064 nm laser treatment. Subjective grading by the patients and blinded dermatologists also confirmed that combination therapy was more successful after one treatment. Although combination treatment had a higher incidence of mild postinflammatory changes, this disappeared within 2 months.

CONCLUSIONS

Concurrent use of the Q-switched 532 nm Nd:YAG laser in combination with the 1,064 nm laser is more effective in pigment clearance than the Q-switched 1,064 nm Nd:YAG laser alone for Hori's nevi.

[Analysis of 602 cases of nevus of Ota and study of ultrastructures on the melanocytes]

OBJECTIVE

To analyze clinical information and efficacy of 602 cases of nevus of Ota, and investigate the histopathology and ultrastructure on the melanocytes before and after Q-switched Alexandrite laser irradiation.

METHODS

Clinical information of 602 cases of nevus of Ota were collected by applying clinical records, checking photos, and inquiry to patients by letters and telephones. Ten cases of biopsies were observed by light microscopy and 6 cases by electron microscopy before and after laser irradiation.

RESULTS

Nevus of Ota included congenital and acquired cases. Skin lesions mainly occurred in adolescence for the acquired cases. The main colours of lesions were brown and blue. The most local lesions were zygomata, temporal regions, and lower eyelids. According to multiple regression, the more treatment times, the better results. The effective rate was 85.20% and 100% after 6 and 9 treatment times, respectively, while the cure rate was 55.72% and 98.46%, respectively. The eyelids involved and Tanino types influenced the treatment times by COX models analysis. Electron microscopy showed many melanosomes in the dermal melanocytes. After laser irradiation, the outlines of the dermal melanocytes were observed, the melanosomes were broken to dense and tiny granules.

CONCLUSIONS

Q-switched Alexandrite laser is safe and effective for the treatment of nevus of Ota. The results of treatment are correlated with the area and size of the lesion. The dermal melanocytes in nevus of Ota can be selectively destroyed by Q-switched Alexandrite laser with less injury around tissues.

Role of skin cooling in improving patient tolerability of Q-switched Alexandrite (QS Alex) laser in nevus of Ota treatment

BACKGROUND

The development of a high-energy laser device with very short pulse duration has revolutionized the treatment of nevus of Ota. Nevertheless, patients still suffer from complications that range from the pain and swelling that occur immediately after laser surgery to post-operative pigmentary changes and scarring. However, the simultaneous use of skin surface cooling and laser surgery may limit the damage of non-target tissue.

OBJECTIVES

To assess whether epidermal cooling reduces the pain and swelling that commonly occur after laser treatment for nevus of Ota.

STUDY DESIGN/PATIENTS AND METHODS

Thirty-seven patients with nevus of Ota were recruited from a dermatology outpatient clinic. Before treatment, the research nurse used an ink pen to divide the lesions into two halves. Half of each lesion was treated with a Q-switched Alex laser system that had a cool sapphire plate in contact as a mean of skin cooling. The other half was treated with the same laser, but with the cooling device switched off. Immediately after treatment, and again 1 week later, the patients answered a questionnaire, which assessed the symptoms that are associated with laser surgery. Dose assessment was performed in each half of the nevus to obtain the optimal fluence that could be used for the treatment of nevus of Ota before the entire half was treated.

RESULTS

There was no difference in terms of the optimal fluence that was used, but in terms of immediate pain the patients associated the side that was treated with the cooling plate with a significantly lesser degree of pain than the non-cooled side (P = 0.001). Eighty two percent of the patients preferred the cooled side to the non-cooled side.

CONCLUSIONS

Pre- and post-operative skin cooling is effective in improving the tolerability of nevus of Ota patients to Q-switched laser treatment. However, the use of cooling during laser treatment of nevus of Ota did not allow the use of higher fluence.

A giant melanocytic nevus treated with combined use of normal mode ruby laser and Q-switched alexandrite laser

We report a combination procedure that can improve the effectiveness of laser removal of giant congenital melanocytic nevi (CMN). A 2-year-old girl with a giant CMN was seen in our outpatient clinic. Histological findings showed a compound nevus without any evidence of malignancy or dysplastic changes. The patient was treated with the normal mode ruby laser and Q-switched alexandrite laser. The lesion was significantly improved in color and cosmetic appearance. Partial hypopigmentation and texture changes were observed. Histological findings showed a marked decrease in the number of junctional melanocytes and the nests in the papillary and reticular dermis. The combined laser treatment is an effective method for the treatment of giant CMN, but further study is warranted to follow-up questions of recurrence and malignant change.

Bilateral Ota naevus

We present the case of a 22-year-old woman, who had presented since the age of 15 a pale-blue spot spread on the right-hand side of her forehead and in her bulbar conjunctiva (first and second branches of the trigeminus nerve), consistent with Ota naevus. A few years later another with similar characteristics appeared on the other side of her forehead, cheek and sclera. No deafness, neurological defect nor visual loss were detected. We comment on the rarity of this case because the patient is Caucasian and also we explain the main complications derived of this disease and consider the therapeutic options.

Effect of Q-switched Alexandrite laser irradiation on epidermal melanocytes in treatment of Nevus of Ota

OBJECTIVE

To investigate injury to epidermal melanocyte by Q-switched Alexandrite laser.

METHODS

Multiple biopsies were performed on 5 patients with nevus of Ota from before irradiation to 1 year after irradiation. Fourteen specimens were obtained for light microscopy, and 17 for transmission electron microscopy.

RESULTS

Melanosomes in epidermal melanocytes were both smaller in size and fewer in number than those in dermal melanocytes. Immediately after irradiation, focal extracellular vacuoles of the basal layer could be observed under light microscopy. Most epidermal melanocytes underwent mild or moderate injury in the form of vacuolated melanosomes, swollen mitochondria, dilation of endoplasmic reticulum, and expansion of extracellular space, retaining intact cell membranes. Normal structures were restored 5 months to 1 year after irradiation, with no depigmentation or hyperpigmentation as seen by light microscopy.

CONCLUSION

Injury of melanosomes in epidermal melanocytes is reversible.

Two cases of late onset Ota's naevus

Ota's naevus is among the dermal melanocytoses that show a distinct pattern involving skin innervated by the trigeminal nerve. Most cases present at birth or manifest clinically in early childhood. Cases of acquired lesions in adult onset have been reported rarely. We present two cases of late onset Ota's naevus which were confirmed by skin biopsies. Both patients underwent Q-switched alexandrite laser treatment with a dose of 8.0 J/cm2 given four or five times at 6 weekly intervals and showed some improvement.

Changes of biophysical properties of the skin measured by non-invasive techniques after Q-switched Nd-YAG laser therapy in patients with nevus of Ota

BACKGROUND/AIMS

The aim of the study was to objectify the effect of a Q-switched Nd-YAG laser on Ota's nevus in view of barrier function, surface contour changes, dermal blood flow, surface color changes and sebum production rate.

METHODS

Fifteen Korean patients with nevus of Ota (between 14 and 54 years of age) were enrolled. All the patients were treated by Q-switched Nd-YAG laser and followed up for 12 weeks. A reflectance spectrophotometer, a colorimeter, laser Doppler flowmetry, a Tewameter, a Corneometer and a Sebumeter were used to make measurements.

RESULTS

Pvalues of less than 0.05 were regarded as statistically significant. In skin reflectance measurements, L* values declined for 4 weeks and increased at 12 weeks, indicating that the brightness of the lesions improved. a* values showed a significant increase at 2 and 4 weeks. On the contrary, b* values decreased at 2 weeks. Transepidermal water loss and dermal blood flux showed identical patterns, showing increases at 2 weeks. The water holding capacity decreased at 2 and 4 weeks, and thereafter showed a delayed recovery. Casual sebum production increased at 4, 8 and 12 weeks. The loss of skin roughness was observed at 4 weeks, recovering at 12 weeks, although statistically insignificant. Reflex spectrophotometry did not reflect the changing properties of the skin.

CONCLUSIONS

Our data suggest a useful model for evaluating physiologic skin changes after laser surgery in patients with nevus of Ota.

Effect of Q-switched alexandrite laser irradiation on dermal melanocytes of nevus of Ota

OBJECTIVE

To investigate the effect of Q-switched alexandrite laser irradiation on dermal melanocytes of nevus of Ota.

METHODS

Multiple biopsies were carried out on 4 patients with nevus of Ota before and after laser irradiation. Altogether 11 samples were examined under light microscope and 14 under transmission electron microscope.

RESULTS

Immediately after laser irradiation, the dermal melanocytes were destroyed, the melanosomes were degenerated with central vesicle formation within most of them, and intradermal round vacuoles appeared. The epidermis remained intact. Three months to 1 year after irradiation, the degenerated melanosomes and cell debris were scavenged mainly by macrophages. Dermal melanocytes gradually decreased. No fibrosis was found.

CONCLUSION

Q-switched alexandrite laser can selectively destroy dermal melanocytes of nevus of Ota and treat the disease safely.

Treatment of Ota's nevus by Q-switched alexandrite laser : therapeutic outcome in relation to clinical and histopathological findings

Ota's nevus is a dermal melanocytic disease which causes serious cosmetic problems for affected individuals. Recently Q-switched lasers with a pulse duration of 100 nsec or less became available for patient treatment. We evaluated the clinical efficacy of the Q-switched alexandrite laser (755 nm, 100 nsec) in relation to the histopathological findings. Fifty-five Korean patients with Ota's nevus were treated with a Q-switched alexandrite laser for three sessions (7.5 J/cm2) at three month intervals. Skin biopsies were taken in all of the patients before treatment and immediately after treatment in five patients. Clinical effectiveness and side effects were evaluated by direct observation and photographs. Pigment clearing was excellent in 27 patients (49%), good in 17 patients (31%), fair in 7 patients (13%) and poor in 4 (7%) patients. Postinflammatory hyperpigmentation developed in 30 patients (55%) which resolved within four months. But there were no serious complications including scarring or textural change. The therapeutic outcome was not affected by color but by depth of the nevus. Nevi of Ota with depth of 1 mm or less were associated with excellent or good results. Q-switched alexandrite laser is a very effective and safe tool for treating Ota's nevus. Depth of 1 mm or less of dermal melanocytes was a good prognostic marker.

Efficacy of the ruby laser in the treatment of Ota's nevus previously treated using other therapeutic modalities

Ruby laser treatment, especially with a Q-switched laser, is remarkably effective for Ota's nevus, although a wide variety of other therapeutic modalities have had limited success. Consequently, laser treatment is now considered the treatment of choice. However, for Ota's nevus previously treated with dry ice cryotherapy (carbon dioxide snow), dermabrasion, free skin grafting, or other methods, therapy is still a challenge, even with the ruby laser. In this study, 14 patients with Ota's nevus previously treated using other modalities were treated using a Q-switched ruby laser. Eight patients previously underwent dry ice cryotherapy, three patients underwent free skin grafting, two patients underwent dermabrasion, and one patient received a cosmetic tattoo. The study group was composed of five male and nine female patients. The ages of the patients at the start of treatment ranged from 5 to 62 years. We concluded, based on the findings of this study, that Q-switched ruby laser therapy can provide favorable results even with lesions previously treated by other therapeutic modalities, provided that the treatment sessions are repeated more frequently and over a longer period of time than those used for untreated lesions and that they are combined with plastic surgical techniques such as scar resection or local flaps.

Light and electron microscopic investigation of the process of healing of the naevus of Ota by Q-switched alexandrite laser irradiation

Melanocytes in the naevus of Ota were destroyed by irradiation using the Q-switched alexandrite laser. This laser is highly selective and highly absorbed by melanosomes. Other cells and tissue components of the dermis remained almost intact. Melanosomes were vaporized or fragmented to subelectron microscopical size, or degenerated. If the irradiated energy was sufficient, melanocytes vanished and large vacuoles several times the size of dermal melanocytes formed at the sites. If it was too weak, dermal melanocytes were also vaporized, but vacuoles formed within them. Nuclei were no longer discernible. Following irradiation macrophages infiltrated the irradiated areas and scavenged degenerated melanosomes and cellular debris. Thus, discoloration of the skin was markedly reduced. Although a few melanocytes and melanophages remained, pigmentation cleared to a satisfactory level. Melanocytes and keratinocytes were also injured in the epidermis; however, the epidermis recovered completely. No scarring was observed.

Treatment of nevus of Ota by Q-switched ruby laser

The effectiveness of the Q-switched ruby laser was investigated in 38 patients with nevus of Ota at more than 10 months after the first irradiation. In 14 patients who were followed-up for a mean of 25.2 months after the first treatment, the effectiveness was evaluated as "excellent" in eight patients (57%), "good" in four patients (28%), and "fair" in two patients (14%). The mean number of irradiation treatments was 7.3 in the "excellent" group, 4.2 in the "good" group, and 3.0 in the "fair" group. In 24 patients who were followed-up for a mean of 13.6 months after the first treatment, the effectiveness was evaluated as "excellent" in eight patients (33%), "good" in 12 patients (50%), and "fair" in four patients (16%). The mean number of irradiation treatment was 5.7 in the "excellent" group, 5.2 in the "good" group, and 2.5 in the "fair" group. Even after repetitive irradiations, good results without scarring were noted in all cases except one where a slight inverted scar was developed. The effective rate tended to be higher in patients who underwent more irradiation treatments and were observed for a longer period of time. Satisfactory cosmetic results were achieved after Q-switched ruby laser therapy for nevus of Ota.

Treatment of nevus of Ota by Q-switched ruby laser

BACKGROUND

There are few reports on therapy for nevus of Ota. Moreover, traditional treatments are largely palliative or risk permanent pigmentary changes and/or scarring.

OBJECTIVE

The efficacy of the Q-switched ruby laser (694 nm, 40 nsec) as a therapy for nevus of Ota was investigated.

METHODS

Nine nevi or portions thereof were irradiated up to six times with 4.5 and/or 7.5 J/cm2 at a mean exposure interval of 3 weeks. Sequential skin biopsy specimens were processed for light microscopy, immunohistochemistry, and electron microscopy.

RESULTS

Cosmetic improvement occurred at both doses in the irradiated parts of the six nevi available for follow-up. No appreciable difference was noted between single and multiple treatments. There was no gross scarring. Light microscopy revealed dose-related immediate injury with more melanophages and fewer dermal melanocytes after irradiation in comparison with control areas. Electron microscopic distinction between dermal melanocytes and melanin-laden macrophages was difficult. A monoclonal antibody to human melanosome-specific antigen type 1 (HMSA-1) was used to distinguish between the two cell populations.

CONCLUSION

Our findings suggest that the Q-switched ruby laser is useful for treating nevus of Ota.

Q-switched ruby laser treatment of benign pigmented lesions in Chinese skin

The Q-switched ruby laser has been demonstrated as an effective choice of treatment for a range of benign pigmented lesions. Its wavelength of 694 nm enables deep penetration of the skin allowing the treatment of both epidermal and dermal lesions. However, this wavelength is selectively absorbed by melanin thereby enabling efficient targeting of the lesion's melanocytes. By utilising a Q-switched pulsewidth of 25 nanoseconds, thermal conduction into surrounding tissues is minimised. Lesions such as nevus of Ota, chloasma, lentigines and cafe au lait have been successfully treated with energy densities ranging from 6 to 12 J/cm2. Four case histories are described in this report. The clinical evidence indicates that pigmented lesions in Chinese skin must be treated with energy densities higher than those used in Caucasian skin to minimise the incidence of hyper-pigmentation. Typically, lesions require a small number of treatments, usually within the range one to six, to effect complete removal. The technique is easy to apply, with no need for anaesthesia, in many cases.

Nevus of Ota: treatment with high energy fluences of the Q-switched ruby laser

BACKGROUND

The nevus of Ota is a benign dermal melanocytic lesion that has previously proved difficult to treat. Recently, the Q-switched ruby laser has been reported to be successful in treating benign pigmented lesions and tattoos.

OBJECTIVE

Our study evaluates the treatment of 16 patients with nevus of Ota with the Q-switched ruby laser (694 nm).

METHODS

Sixteen patients with nevus of Ota were treated with the Q-switched ruby laser with a pulse width of 28 nsec and energy fluences ranging from 7.5 to 10 J/cm2. Response to treatment was assessed by an independent investigator with photographs.

RESULTS

The average number of treatments was 3.8 per patient. After two treatments, 44% of patients showed a 50% or greater improvement. After three treatments, 85% of patients showed a 50% or greater improvement; after four treatments, 100% of patients showed 50% or greater improvement. No patients had permanent textural changes or scarring.

CONCLUSION

High-energy fluences of the Q-switched ruby laser lead to significant improvement without scarring of nevus of Ota after a few treatments.

[Malignant transformation of a nevus of ota]

The association of naevus of Ota and choroidal melanoma is reported in a 83 years-old monophtalm caucasian man. Because of no tumoral spreading in this monophtalm patient, the tumor is treated by physical technique with iridium disc. In the next months, complications of this physical treatment appeared. The authors remind the clinical aspect of the disease and the different associations, also that the frequency of coming of the main complication of the affection: the choroidal melanoma.