Alexandrite lasers for effective hair removal - Dr. Jean Luc Levy

A clinical report

Introduction

Not only are there various application sites, different skin types and hair characteristics, but also there are discrepant number of treatments and versatile protocols. Thus, it is very hard to assess the success rate of the procedure in general. This clinical report will not include a statistically significant sample size, but it will be limited only to a particular skin area i.e. axillary area.

The laser hair removal often refers to unwanted hair removal procedure, but it can also be related to treatments of hirsutism and hypertrichosis. The main targets for laser hair removal are terminal hairs, well pigmented and coarse, with a dense column of keratinized melanocytes. It is well known that the hair growth cycle consists of 3 phases: anagen, catagen and telogen phase. The hair must be treated during the anagen phase, which is an active growing phase. The hair follicles differ even over the same skin area, which influences the subsequent heat transfer. The hair follicle depth is usually between 1mm and 6mm in general, with the hair bulge located more superficially comparing to the hair bulb.1-3 Both, hair bulge and hair bulb, represent the hair removal targets. The selective photothermolysis theory lies behind the laser hair removal procedure, where melanin in the hair shaft, as the main chromophore for hair removal, is targeted by the laser beam while sparing epidermal melanin and perifollicular dermis in the surrounding tissue.4 The pulse width should be less than thermal relaxation time of hair follicle (between 40 and 80ms) in order to avoid undesirable side effects. The absorption in melanin decreases with longer wavelengths. Moreover, the scattering mechanism decreases as a function of wavelength, resulting in deeper penetration inside the dermis. The increased spot size also guarantees improved optical penetration inside the skin.1,5,6

The Alexandrite 755nm long pulse laser is the laser of choice for the most effective hair removal procedures. Its expansion and indispensability in the market started in 1996. Its great absorption in melanin and low affinity in oxyhemoglobin makes this wavelength ideal for hair removal of the Fitzapatrick skin types I-IV.

Moreover, the side effects with Alexandrite laser are minimal if the cooling system is well controlled before the session even in dark skin types.5,8

Quanta System is one of the very few manufacturers of Alexandrite lasers. The Quanta System’s Light A and Domino laser platforms are state-of-the-art Alexandrite platforms which assure the highest success rate in laser hair removal treatments. In this clinical study, the Light A laser was used. Nevertheless, the Alexandrite laser can be found among the other laser platforms of Quanta System, such as Light A*, Light 4V, Matisse HR, Q-Plus * 2, DaVinci A and Duetto M.T.

Objective

This study evaluates the performance of hair removal procedures with Light A on axillary area. The aim of the treatment was evaluation of hair shaft reduction in axillary area.

Methods

The Light A treatment of axillary area was performed with the following parameters selected on the platform’s touch screen: spot size 14mm, repetition rate at 1.5 Hz, pulse width of 20ms and fluence in the range of 14-22 J/cm2. The settings provided the treatment speed of 2.3 cm2/s. The laser handpiece contained the integrated contact skin cooler preset at 4 °C for epidermal protection. The relation between speediness of the repetition rate and cooling system requires 1,5 Hz Maximum for the best comfortable treatment. The in-vivo human study enrolled 16 female patients in the age group between 21 and 55 years (average age of the patients was 41 years), with 4 patients belonged to Fitzpatrick skin type II, 10 to type III and 2 patients to type IV. The two patients with skin type IV were treated with the fluence of 14 J/cm2, in order to avoid potential side effects. Moreover, the 2 patients were treated with topical corticosteroids post-treatment. All the patients were healthy with normal endocrine function.

For all the patients it was the first laser hair removal procedure on axillary area. The axillary hair were shaved or cut at 1 mm length from the skin immediately before the treatment. The topical anaesthetic cream was not applied before treatment to the patients. The post-treatment care included application of zinc oxide cream immediately after the treatment.

The patients were treated 5 times with 4-5 weeks treatment interval. The hair reduction was on standardized pictures by one independent observer and one operator during the study at assessed 3 months (which coincides with the duration of the axillary hairs’ telogen phase) and 6 months after the initial treatment. We used a classic quartile grading scale for hair reduction (1: 0-25 %, 2: 26-50%, 3: 51-75 %, 4: 76-100%).The patient evaluated the result as excellent, good, moderate or poor results.

Results and conclusions

All the patients experienced low level of discomfort during the Light A laser treatments .The level of pain relief was 3,6 on a 1-10 Visual Analogic Scale.

After the treatment, perifollicular erythema and edema were present, which persisted up to maximum 1 day after treatment, depending on the hair colour, thickness and density. Even the two patients with the skin type IV have not experienced any incidence of complications, like transient hyper pigmentation or any other epidermal pigmentary alteration. Neither hypo pigmentation nor scarring was present in any of the treated patients.

The pulse width of 20 ms applied to all the patients affected the terminal hair follicles, sparing the epidermal melanosomes, which are sensitive only to very short pulses.

The follow-up visits, after 3 and 6 months from the initial laser treatment, showed progressive improvement in hair reduction with a partial re-growth at session 3.This observation is due to the synchronized hair after 2 sessions.

The follow-up after 6 months after the last session showed the final and stabilized results.

In all patients with terminal brown-black hair, more than 79 % hair reduction was observed. The remained hair are thinner and lighter and need sometimes one session more or a finished treatment with one electrolysis session to obtain 100% hair reduction. The patient graded the results as excellent and always over both observer and operator.

The average time to treat the axillary area was 7 minutes including the shaving and cleaning before laser time.

In general, all 16 patients were satisfied with the laser hair removal results declaring that the treatments were virtually painless. The 2 patients with skin type IV and other 2 with skin type III (25% of the patients) needed all 5 treatments in order to reach satisfactory hair reduction. Even 9 patients i.e. 3 of them with skin type II and other 6 with skin type III (56% of the patients), where terminal hairs were dark and coarse, succeeded with the satisfactory hair clearance after only 3 treatments.

In conclusion, axillary zone is a non hormonal dependent area. This cosmetic treatment demonstrated significant reduction in hair re-growth without noticeable epidermal side effects. It can be concluded that hair removal treatments using the Quanta System’s Light A laser platform are very safe and effective when they are synchronized with the hair growth cycle typical for the applied anatomic location. The study demonstrated high success rate of the treatments at the 6-month follow-up visit.

Further research should be focused on finding the optimal parameters related to different hair shaft thickness and variable colours.

Others areas such as bikini line or facial areas will be evaluated with the same laser.

Female patient, 38 years old, Fitzpatrick skin type III:

Before treatment

After treatment: 6-month follow-up