Q-Switched 1064 nm Nd:YAG Laser in Treating Axillary Hyperpigmentation in Filipino Women With Skin Types IV-V

January 2020 | Volume 19 | Issue 1 | Original Article | 66 | Copyright © January 2020


Published online December 5, 2019

Irene Gaile C. Robredo

St Luke’s Medical Center Global City, Taguig City, Philippines; Asian Hospital and Medical Center, Muntinlupa City, Philippines; beautiqueMD, Taguig City, Philippines; dermHQ, Makati City, Philippines

to effectively treat PIH. Topical treatment with depigmenting agents such as hydroquinone, keratolytic agents, retinoids or corticosteroids has been shown to be effective as a stand-alone treatment or in combination with other topicals, oral medication or procedures mainly influencing epidermal PIH. Dermal PIH which is characterized by deeper pigmentation does not respond well to these modalities.2,5,7 Laser and light-based therapies provide alternatives or adjuncts to topical therapy, especially in refractory cases. Typically, short wavelength lasers are efficiently absorbed by epidermal melanin while longer wavelengths penetrate deeper with more selective absorption by dermal chromophores enabling safer treatment options for patients with darker skin type.2,8 In recent years, a variety of lasers have been studied. Q-Switched Ruby (694nm), Alexandrite (755nm), and Neodymium:yttrium aluminum garnet (Nd:YAG) (1064nm), as well as fractional lasers (various wavelengths) have been clinically studied exhibiting statistically significant improvement in pigmentation up to complete clinical clearance in some cases.7 The Q-Switched (QS) Ruby and Alexandrite lasers have been reported to worsen lesions in dark-skinned patients and generally not recommended for this patient group. The QS Nd:YAG 1064nm laser was shown to be highly effective in darker skin type patients with various PIH etiologies.9 Picosecond lasers have also been reported in the treatment of pigmentation and PIH that proved difficult to treat with conventional QS lasers.10

Axillary hyperpigmentation is a frequent dermatological complaint, characterized by dermal and epidermal PIH mainly associated with women of darker skin types. Etiological theory associates axillary hyperpigmentation of a form of post inflammatory hyperpigmentation due to continuous irritation due to hair removal, cleansing, tight cloths, or innate darkening from genetic related factors.11 The purpose of this case study was to evaluate the efficacy of a 1064nm nanosecond QS Nd:YAG laser in the treatment of axillary PIH in Filipino women with Fitzpatrick skin types IV-V.

MATERIALS AND METHODS

Study Design
Nine (9) female patients, aged 20 to 52 years (mean age 39 ± 10 years), with skin types IV-V and bi-lateral underarm hyperpigmentation (18 axillae) were included in this prospective study. Verbal and written informed consent were obtained. The patients were in good health and were not treated with concomitant whitening or depigmenting agents.

All 18 axillae were treated with a QS Nd:YAG (1064nm) laser (Alma Q, Alma Lasers GmbH, Nürnberg, Germany). Treatment was carried out according to the following treatment protocol: four (4) passes over the treatment area with a focused handpiece, 7 mm spot size, fluence of 2.6mJ/cm2 until total energy accumulation reached 800 kJ. Case study design included a 10-week treatment protocol, which consisted of 4 treatment sessions at 2 weeks intervals and a follow-up visit at one and three months following the fourth treatment.

Clinical Evaluation
Primary end point of the study was reduction in axillary hyperpigmentation. Pigmentary changes were assessed by calculating the L* (luminosity) according to the Von Luschan's Chromatic classification scale (Figure 1). Improvement was assessed by comparing the difference (L*Δ) between target treatment area of the axilla and a non PIH affected area (L*Δ= axilla–periaxilla), at baseline and at the final follow-up visits. Assessment was carried out by the treating physician and by two other objective evaluators. Clinical improvement was assessed by the GIAS score (stages of improvement scoring: 1= very much improved, 2= much improved, 3= improved, 4= no change, or 5= worse outcomes) both by the treating physician and the patients throughout the study. Safety parameters included treatment related adverse events and pain, scored on a 10-point visual assessment scale (VAS scale), recorded after each treatment.