A Retrospective Study on the Characteristics of Treating Nevus of Ota by 1064-nm Q-switched Neodymium-doped Yttrium Aluminum Garnet Laser.

BACKGROUND: The Q-switched neodymium-doped yttrium aluminum garnet (QS Nd:YAG) laser has a significant effect in treating nevus of Ota, but there is lack of a retrospective study about the characteristics of efficacy. AIMS AND
OBJECTIVES: To retrospectively analyze the correlation between the clinical characteristics and efficacy, complications, recurrence of QS Nd:YAG laser in treating nevus of Ota.
MATERIALS AND METHODS: One hundred and seventy-one Chinese patients (144 female, 27 male) of nevus of Ota were treated with the 1064-nm QS Nd:YAG laser. All cases were treated with fluencies of 4-8 J/cm(2) and a spot size of 2-4 mm. Clinical photographs were taken before every treatment and patients were followed up by their clinicians.
RESULTS: One hundred and forty-five patients (84.8%) acquired more than 75% improvement with an average of 4.6 sessions. The treatment effect has no significant correlation with sex (P > 0.05). The blue-black and brown lesions improved more than the light-brown (P < 0.05). Hyperpigmentation affected two (1.2%) of the patients and hypopigmentation affected one patient (0.6%). No other adverse effect was observed. Recurrence was seen in two patients (1.2%).
CONCLUSION: The 1064-nm QS Nd:YAG laser is effective with rare complications and recurrence in the treatment of nevus of Ota. The efficacy correlated with lesion color, which is meaningful to estimate the prognosis.

What was known?

The Q-switched neodymium-doped yttrium aluminum garnet (QS Nd:YAG) laser has a significant effect in treating nevus of Ota, but there is lack of a retrospective study about the characteristics of efficacy.

Learning Points

The 1064-nm Q-switched neodymium-doped yttrium aluminum garnet laser is effective with rare complications and recurrence in the treatment of nevus of Ota

The efficacy and prognosis can be estimated before treatment.

Introduction

Nevus of Ota is a benign dermal melanocytic nevus that commonly affects the Asians.[1] Clinically, it is presented as a blue or brownish black macule along the distribution of the first and second branches of the trigeminal nerve, involving the sclera.[234] In the last 20 years, Q-switched (QS) lasers have been used effectively in the treatment of nevus of Ota, with minimal complications and adverse effects. There are three kinds of QS lasers, including QS ruby laser, QS alexandrite laser (QSAL), and QS neodymium-doped yttrium aluminum garnet (QS Nd:YAG) laser, all of which are based on the principles of selective photothermolysis.[56] A retrospective study of the complications of QS Nd:YAG laser in the treatment of nevus of Ota has been reported, and a retrospective study of QSAL in treating nevus of Ota has been performed, too.[37] However, there is lack of a long-term retrospective study about the efficacy and influencing factor, as well as the recurrence. Herein, we performed a retrospective study on 171 patients that treated with QS Nd:YAG laser, to analyze the efficacy of patients and provide a basis on the estimate of prognosis before treatment.

Materials and Methods

Subjects and setting

One hundred and seventy-one nevus of Ota patients ranging in age from 2 to 55 years were treated with QS Nd:YAG laser. All cases were treated at the laser center of the Department of Dermatology, Northwest Hospital, Xi’an Jiaotong University, from 1997 to 2008. All of our patients are the skin Type III according to the Fitzpatrick skin types. A QS Nd:YAG laser ray with a wavelength of 1064 nm, spot size of 2–4 mm, and pulse duration of 10 ns was used. Most of the time we used the 4 mm spot size, and we used 2 mm spot size in some special conditions, such as the lesions in the edge of eyelid and nostrils edge. Patients were treated with fluence between 4 and 8 J/cm2 and a spot size of 2–4 mm with 1–12 sessions. The interval between treatment sessions was 3–9 months. Clinical response was defined as immediate whitening without purpura. Patients were advised to avoid exposure to the sun for at least 6 months after the treatment. In all cases, lidocaine cream was applied to the lesion 1 h before treatment and ice compress for 1 h after the treatment. Clinical photographs were taken before and after each session, and the complications and recurrences were recorded.

The degree of the efficacy of the QS Nd:YAG laser was established on visual inspection of the photographs according to the percentage of pigmentary clearing, which is divided into five grades as follows:

Minimal improvement (<25%)

Moderate improvement (26–50%)

Marked improvement (51–75%)

Significant improvement (76–99%)

Complete clearing (100%).

Statistical analysis was performed using SPSS 17.0 software. The relationship between lesion color and efficacy was determined by using Chi-square test. P < 0.05 was considered statistically significant.

Results

Clinical features

Demographic data of the patients of the study are listed in Table 1. Females were more likely affected nevus of Ota than males (144 female: 27 male, female:male = 5.33:1). More than half of the patients were affected at birth (57.3%), and 94.7% affected before 20-year-old. According to the Tanino classification described previous,[3] the majority of patients were Type I (50.3%) and Type II (46.2%). Demographic data of the lesion color showed that the predominant color was blue-black (66.1%), followed by brown (23.4), and light-brown (10.5) [Table 2].

Table 1

Demographic data (n=171)

Table 2

Demographic data of the lesion color

Laser therapy effect

One hundred and forty-five patients (84.8%) acquired more than 75% improvement with an average of 4.6 sessions [Table 3]. The treatment effect has no significant correlation with sex (P > 0.05) [Table 4]. The lesions of blue-black and brown improved more than the light-brown (P < 0.05), and no significant difference the color between blue-black and brown (P > 0.05) [Table 4]. These data suggested that the laser therapy effect would be influenced depending on the different lesion color.

Table 3

The degree of clearing

Table 4

The correlation between sex/lesion color and effect

Complications

Hyperpigmentation affected two (1.2%) of the patients and hypopigmentation affected one patient (0.6%). No other adverse effect was observed, such as persistent erythema and scarring.

Recurrence

Two patients (1.2%) who had been completely cleared developed recurrence at the same site as before. The time of recurrence are 4 and 10 years, respectively, for these two patients.

Discussion

Nevus of Ota is a congenital or acquired pigmentary disorder of unclear etiology.[89] Nevus of Ota occurs more commonly in Asians, and affects females predominantly, inducing serious cosmetic, and psychological implications.[810] All of the QS Nd:YAG (1064 nm), QS alexandrite (755 nm), and QS ruby (694 nm) lasers treated nevus of Ota successfully.[38] However, the correlation between the clinical characteristics and the efficacy by QS Nd:YAG has not been described clearly. Moreover, the recurrence condition of nevus of Ota is rarely described in the previous reports. In our study, we analyzed the efficacy and influence factors of 171 patients who were treated with QS Nd:YAG, revealing some characteristics of this disease.

Demographic data showed nevus of Ota affected females 5.33 times more than males, which is consistent with previous reports.[2311] More than half of the patients were affected at birth (57.3%), and 94.7% affected before 20-year-old. The cosmetic disfigurement is harmful to child and adolescent mental health. Therefore, early treatment was advised. Technically, the nevus of Ota should be treated with laser as soon as possible after diagnosed. However, with considering the pain tolerance and the risk of anesthesia in children, we usually advise the patients do the treatment after 3-year-old actually.

All of the four lesions types (Tanino classification) acquired good improvement, and 145 patients (84.8%) acquired more than 75% improvement with an average of 4.6 sessions [Table 3], which was superior to the effect reported by Chan et al.[7] In our study, the treatment effect has no significant correlation with sex. The lesions colors of our patients were described as blue-black, brown, and light brown. The efficacy data showed the lesions of blue-black and brown improved more than the light-brown lesions, and no significant difference the color between blue-black and brown, which suggested that the therapy effect of Nd:YAG laser would be influenced depending on the different lesion color. In addition, it is interesting that the elimination of the forehead lesions was easier while lesions around the eyes harder by Nd:YAG laser in our study. Although the definite mechanism was not clear, the efficacy and prognosis of patients can be estimated before treatment based on our clinical experience.

Hypopigmentation and hyperpigmentation were common complications seen after Nd:YAG treatment reported before, 7.6% and 2.9%, respectively.[7] In our study, hyperpigmentation affected two (1.2%) of the patients and hypopigmentation affected one patient (0.6%). No other adverse effect was observed such as persistent erythema and scarring. These data were less than the previous report, which probably resulted from the lower fluence.

Recurrence is rare in nevus of Ota. The true recurrence rate means the patient these achieved complete clearance developed nevus of Ota again after a few years. In our study, the true recurrence rate is 1.2%, which is similar to previous reports (1.2%, 0.6%, and 0.8%).[237] Sun exposure and pregnancy may be considered as the possible reason of recurrence.[2] Both of the two patients in our study had no remarkable reason. Lesions usually occurred in the initial position in patients with recurrent, with smaller area compared the 1st time. Therefore, it might be that patients do not need to worry about the recurrence.

Conclusion

The treatment of nevus of Ota by QS Nd:YAG laser is safe and effective, with rare complications and low recurrence rate. The laser therapy effect would be influenced depending on the different lesion color, which is meaningful to estimate the prognosis.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

What is new?

The 1064-nm QS Nd:YAG laser is effective with rare complications and recurrence in the treatment of nevus of Ota. The efficacy correlated with lesion color, which is meaningful to estimate the prognosis. In addition, the forehead lesions were easier to be eliminated while lesions around the eyes were harder by Nd:YAG laser. Based on our study, the efficacy and prognosis of patients can be estimated before treatment.