Vellus hair removal with 1064‐nm neodymium: Yttrium–aluminum–garnet laser: A prospective study

Dear Editor,

Hair removal lasers have become popular because of their more permanent results. In fact, there are several other options for patients suffering from hirsutism including shaving, bleaching and the use of depilating agents, but all of them are temporary methods. As a result, some more permanent modalities such as laser hair reduction (LHR) have emerged and multiple studies have shown their effectiveness and long‐lasting results in reducing undesired hair growth. ¹ , ²

Although existence of many studies regarding laser‐assisted terminal hair removal, there are not enough data for unwanted vellus hairs in the literature. Hence, we conducted a prospective study at the laser clinic of the Dermatology Department at Razi Hospital, Iran in 2018 to evaluate the efficacy of 1064‐nm neodymium: yttrium–aluminum–garnet laser on arm's vellus hair reduction as a useful reference for patients who want to try this laser. Eighteen female volunteers of 19 to 45 years of age with Fitzpatrick skin types II–IV and brown to black hair who wished to remove their unwanted hairs were recruited. The Ethical Committee of Tehran University of Medical Sciences approved the protocol of the study and after signing an informed consent by patients and taking a complete medical history, all of patients received three treatment sessions with an 8‐week interval. At each session, patients were treated with three passes of the 1064 nm, long‐pulsed Neodymium: Yttrium‐aluminum‐garnet (ND:YAG) Laser (Fotona, Slovenia) with pulse duration of 1.6 ms, fluence of 20–25 J/cm² and frequency of 3–3.6 Hz on their arm's vellus hair.

Patients with active viral or bacterial skin diseases, active dermatosis on the treatment area, or severe illness were excluded, as well as pregnant or lactating women, anyone with a scar or keloid formation history, and patients with a disturbed hormonal condition. Patients who had laser or electrolysis treatment sessions within the last 6 months and those taking isotretinoin or anticoagulant medications were also excluded.

Trichoscopy was performed both before and after the laser treatments. The percentage of hair loss was calculated by counting the number of hairs with an area of 2 * 2 in the test region of the arm. The percentage of hair loss was recorded after a single‐blind trichoscopic measurement which was performed twice during the study by two independent dermatologists and the average of their reported values was considered as final percentage of hair loss.

A visual analog scale ranging from 0 to 10 was used to evaluate the average hair loss (number decrement or reduction in thickness) according to trichoscopic results. Laser treatment complications include hypertrichosis, persistent erythema, hyperpigmentation, and hypopigmentation were recorded.

Standard photos of patients were taken at the 1st day before laser therapy and after 2 months of follow‐up. These photographs were assessed by two professionals randomly and in a single blind manner.

Our study population age range was from 19 to 45 years with a mean of 32.94 ± 6.21 years. The most common phototype among our patients was type III (66.7%), followed by type II (27.8%) and there was just one person with type IV (5.6%) (Table 1). The most of hairs were black (77.8%) followed by dark brown (16.7 %) and brown (5.6 %).

TABLE 1.

Baseline characteristics of patients enrolled in the study.

Patient number	Percentage of hair thickness reduction	Percentage of hair reduction	Fitzpatric skin types	Age
1	60	35	3	35
2	0	5	3	33
3	20	11	3	43
4	40	7	3	45
5	40	28	3	26
6	60	80	3	37
7	40	38	3	30
8	40	88	3	25
9	40	3	2	33
10	80	68	3	35
11	40	38	2	34
12	30	37	3	30
13	30	48	2	27
14	20	14	2	35
15	30	26	3	19
16	60	46	4	37
17	30	21	3	35
18	50	63	2	34

Based on hair density recorded at the beginning and 2 months after the last treatment session, the mean hair reduction was 36.51 ± 25.46, and the mean hair thickness reduction was 39.44 ± 18.30. We did not find any significant difference in reduction in number or thickness of vellus hair regarding skin phototype or age (p‐values: 0.905 and 0.324 for number and 0.515 and 0.596 for thickness, respectively).

The efficacy of Nd:YAG laser in terminal hair reduction was reported between 60% and 80% in various studies. ³ , ⁴ , ⁵ However, its clinical efficacy regarding vellus hair reduction was not statistically significant in this study and we could not find any similar study in literature to compare our results with. Considering our limited number of patients and laser sessions, further prospective studies with more patients, longer duration of laser treatment, and using various setting parameters including higher fluence and longer pulse duration are needed to validate our results.

AUTHOR CONTRIBUTIONS

Parvaneh Hatami, Pedram Nourmohammadpour, and Maryam Nassimi performed the research. Arghavan Azizpour and Roya Nemati designed the research study. Zeinab Aryanian and Zahra Sheikh analyzed the data. Parvaneh Hatami and Pedram Nourmohammadpour wrote the paper. Arghavan Azizpour and Zeinab Aryanian supervised the project.

CONFLICT OF INTEREST STATEMENT

The authors declare that they have no competing interests.

DATA AVAILABILITY STATEMENT

The data that support the findings of this study are available from the corresponding author, upon reasonable request.