Near Infrared Pulsed Light for Permanent Hair Reduction in Fitzpatrick Skin Types IV and V

INTRODUCTION

The presence of excessive facial hair in women causes significant emotional distress and has a negative impact on their quality of life; so much so that in one study, women with polycystic ovarian syndrome (PCOS) rated excessive facial hair to have a larger impact on quality of life than other manifestations of PCOS such as infertility and menstrual problems.[123] Since hypertrichosis is a cosmetic concern, the method used for hair removal must not only be practical but also cosmetically acceptable and has minimum side effects.

Temporary hair removal methods (shaving, waxing, depilatory creams, threading, etc.,) are convenient and inexpensive methods to control hair growth but require high maintenance. Bleaching with chemicals can lead to contact sensitisation and toxicity.[4] This is why women have been constantly looking for better and newer options of hair removal, especially those that offer permanent hair reduction.

Permanent hair removal (i.e., permanent damage to the follicle) is achieved only by electrolysis which is a painful and very time-consuming procedure.[5] It also leads to pigmentation and scarring.[4] Hence, LASER and intense pulsed light (IPL) devices, found efficient and safe by many studies, have gained popularity in recent times.[678] Commonly used LASER devices include ruby (694 nm), alexandrite (755 nm), neodymium-doped yttrium aluminium garnet (Nd: YAG) (1064 nm) and diode (800–810 nm).

In this prospective study, we assessed the efficacy and safety of super hair removal (SHR) module of pulsed light source using a near infrared wavelength of 810 nm. It is believed that it is more suited for Indian skin types, works on a low fluence (1–7 J/cm²), high pulse repetition rate (3 Hz) and a contact cooling system which minimises pain. Although studies have found this system to be safe and effective, most of these studies have been done on fairer skin types.[679] Hence, we would like to do a study to evaluate the same in Fitzpatrick skin Types IV and V. Further, this study also aims to evaluate if there is a difference in response amongst those with PCOS and those without.

MATERIALS AND METHODS

RESULTS

Twenty-four patients were included in this study out of which 12 were diagnosed to have PCOS based on USG and hormonal evaluation. Age of the patients ranged from 18 years to 34 years. Eleven of these patients had Fitzpatrick skin type IV, and thirteen had skin type V. All patients completed six sittings.

Hair reduction for the upper lip in our patients ranged from 33.15% to 74.39% with an average reduction of 52.87%. The average reduction seen in patients with PCOS was 50.98% and in those without PCOS was 54.77%. This difference was found to be insignificant by unpaired t-test (P = 0.376).

For chin, the average hair reduction was 73.81% ranging from 50.33% to 91.37%. Average reduction in those without PCOS was 74.37% while that in those with PCOS was 73.25%. The difference between the two groups was found to be insignificant by unpaired t-test (P = 0.828) [Table 1].

Table 1 Results

Out of 24 patients, 22 did not complain of any side effect. One patient complained of burning sensation in 2 of the 6 sittings, and one patient complained of pain during the procedure in one sitting over the upper lip. There was no post-inflammatory pigmentation/scarring/burn in any patient.

Out of 24 patients, 19 showed reduction in hair thickness and density by two grades, whereas one and four patients showed reduction by one and three grades, respectively.

Patient satisfaction score ranged from 4 to 9; the average being seven for both with or without PCOS [Figures 1–4].

Close

Figure 1

Upper lip, before 1^st sitting

Export to PPT

Close

Figure 2

Upper lip, after 6 sittings

Export to PPT

Close

Figure 3

Chin, before 1^st sitting

Export to PPT

Close

Figure 4

Chin, after 6 sittings

Export to PPT

DISCUSSION

IPL devices are non-laser high-intensity light sources using a high-output flash lamp to emit non-coherent light of broad wavelength, usually in the 500–1200 nm range.[10] This technology was first used in 1996, to treat a cohort of eighty patients with treatment-resistant facial port wine stains in Germany.[11] Today, it is used for the treatment of various vascular and pigmented lesions as well as for permanent hair reduction.[12] Its use in hair removal is based on the principle of selective photothermolysis, target chromophore being melanin at the hair bulb causing relatively selective destruction of the hair bulb at suitable wavelengths.[13] It has been proposed that damage to the isthmus and upper stem interferes with the interactions between dermal and epidermal germinative cells, inhibiting or altering the normal hair cycle.[14]

Our study found this method to be efficacious with an average reduction of 52.87% over the upper lip and 73.81% over the chin in six sittings. This corresponded with a study by El Bedewi who found 70% reduction in facial hair for skin Types IV and V.[15] There were a few studies that showed a higher reduction in hair, but a higher fluence was used in all these studies and the number of sittings and the body part varied.[1617] Furthermore, we noted that the hair reduction was more over the chin than the upper lip. This is contradictory to the view of Kolinko and Littler who proposed that areas with thick skin such as the chin respond less favourably as compared to areas with relatively thin skin.[18] A higher fluence can be tried for the upper lip area as compared to the chin area to get similar results. This, however, must be weighed against the possibility of higher side effects considering that the skin over the upper lip is thinner than the chin.

On comparing with other lasers, IPL was found to be more efficacious than long-pulsed Nd: YAG laser in one study. A another non-comparative study using long-pulsed Nd: YAG showed greater hair reduction than that observed in our study.[8] Hair reduction with alexandrite laser has been found to be more in two studies.[219] Of these, the study by McGill et al. was a split-face study in a single patient with PCOS, and their conclusion was limited to those with PCOS only. Another study by El-Badawi et al. showed comparable hair reduction with both lasers. As compared to diode laser, Klein et al. found IPL to be less effective.[6] However, it must be noted that most of these studies were done on fairer skin types and on varying body parts. Table 2 gives a brief summary of some studies comparing IPL devices with other devices [Table 2].

Table 2 Some studies comparing intense pulsed light with other devices for permanent hair reduction

Patients with PCOS did not show any difference in efficacy or safety profile in our study in terms of hair reduction and reduction in grade of thickness and hair density.

Side effects reported by IPL hair reduction have been infrequent and transient, including erythema, isolated vesicles, minimal scarring, pain, burning, pigmentary changes, crusting and perifollicular oedema.[23] All studies have found IPL to be safe.[910121516232425] In our study, one patient each experienced mild transient pain and discomfort, both over the upper lip. Apart from a study by Karaca et al. who found that pain experienced during the procedure was less with alexandrite laser as compared to IPL, most studies have found IPL to be more tolerable and have less side effects than alexandrite, diode and long-pulsed Nd: YAG lasers.[2681926] This could be due to the fact that in other lasers, the temperature can rise to 700°C and cause burns and pigmentation if not used with extreme caution. Deeper penetration of such high temperatures can cause alterations in the dermis and pain.[26] Contrary to this, IPL systems use a controlled IPL source as its source of energy operating at approximately 50°C and a cooling system which minimises pain. Different IPL systems use different cooling systems such as forced refrigerated air, contact cooling tips (used in our machine) and cryogen spray.[27]

One of the notable findings in our study was that even though all patients had reduced hair counts at the end of six sittings, three patients showed a slight increase in counts in intermediary sittings. This could be explained by the phenomenon of paradoxical hypertrichosis. It is the paradoxical increase in hair counts due to subtherapeutic thermal injury causing induction of hair cycle and activation of surrounding dormant follicles. This is most likely due to use of suboptimal fluence.[1428] The hair grown as a result of this is usually fine and dark.[14] Studies have shown that the incidence of this side effect is up to 10%, and face is a common site.[28]

The major limitation of our study is relatively small sample size. We recommend further studies in this field on Indian skin types and those that give results individually for different body areas. Furthermore, based on the fact that transient paradoxical hypertrichosis was seen in three patients and the incidence of side effects was low in our study, treatment with higher fluence may be tried to see if better reduction can be obtained with minimal side effects. This is supported by higher hair reduction in other studies with greater fluence used.[816]

CONCLUSION

The efficacy of IPL device in permanent hair reduction is comparable to the popular laser devices used today, with superior safety profile compared to other devices.