Hyperpigmentation Post Laser Hair Removal in Patients... : Journal of Dermatology and Dermatologic Surgery (2024)

INTRODUCTION

Unwanted hair is a common complain that is seen in dermatology clinics. The laser is a popular modality for hair removal in both males and females. Many laser devices are used for hair removal including long-pulsed (LP) 694-nm ruby, LP 755-nm alexandrite, LP 810-nm diode, and LP 1064-nm neodymium-doped yttrium aluminum garnet.[¹]

Although laser hair removal (LHR) is generally a safe procedure, many adverse effects (AEs) have been reported. AEs are mainly related to the partial absorption of the laser energy by the epidermis leading to unwanted collateral epidermal damage.[²] Using cooling devices or longer wavelength lasers can minimize the risk of such damage.[¹] Commonly reported AEs of LHR include pain and transient erythema.[³] More severe side effects include burns, blistering, hyperpigmentation, hypopigmentation, and scarring.[³⁴⁵] Hyperpigmentation is commonly seen in individuals with dark skin and is usually a major esthetic concern, especially in the Middle East. Despite that, studies on risk factors for the development of hyperpigmentation post LHR are relatively limited.

We have observed that many of our patients who are taking Vitamin D are complaining of hyperpigmentation post LHR. Considering the documented role of Vitamin D in melanogenesis, we hypothesized that the oral intake of Vitamin D might be a risk factor for developing hyperpigmentation post LHR. The aim of this study is to assess the prevalence of hyperpigmentation post LHR in patients taking Vitamin D supplements.

METHODS

This is a cross-sectional study of patients who had LHR in a private dermatology clinic in Riyadh, Saudi Arabia. It was conducted between June 2017 and December 2017. The study was approved by the ethical committee in Al-Imam Muhammed bin Saud Islamic University (HAPO-01-R-011). Informed consent was obtained from all enrolled subjects.

Each patient was interviewed by the laser specialist during the clinical evaluation for LHR. We have excluded any patient who was diagnosed with any dermatological disease typically associated with hyperpigmentation (e.g., lichen planus). The collected data include age, gender, skin phototype, and regular sun exposure pre- or post-LHR. In addition, the details of LHR in the past 6 months were documented including the number of sessions and the type of laser used. Next, patients were asked if they have been taking Vitamin D supplements and/or other medications regularly during the past 6 months. Finally, they were asked whether they have observed hyperpigmentation after any of those LHR sessions.

Statistical analysis

Data were entered, coded, and analyzed using SPSS version 20.0 (IBM Inc., Chicago, Illinois, USA). Descriptive analysis for categorical variables was presented in the form of frequencies and percentages and in the form of mean ± standard deviation for numerical variables. Chi-square test was used to compare proportions. In addition, multivariate logistic regression analysis was performed to identify factors that are independently associated with hyperpigmentation post LHR. The P values were adjusted using the Bonferroni correction, and any output with a P < 0.006 was interpreted as an indicator of statistical significance.

RESULTS

A total of 508 patients with a mean age of 29 ± 9 years were included, 70.4% of whom were females [Table 1]. Some data were missing but are within the 10%–15% acceptable range. The majority of patients had skin Types III and IV (93.8%). Vitamin D was taken by 18.3% during the past 6 months and 17.2% reported taking other medications. Hyperpigmentation post LHR was observed by 10.8% of the patients. The number of LHR sessions was variable and ranged from 1 to more than 3 sessions in the past 6 months. LP 755-nm laser was the most commonly used laser followed by LP 1064-nm laser. Most of the patients (88.9%) did not get exposed regularly to the sun over the past 6 months.

Univariate analysis showed that hyperpigmentation was significantly more common in females and with taking medications in general including Vitamin D supplements [Table 2]. After performing multivariate logistic regression analysis, none of the factors were independently associated with hyperpigmentation post LHR [Table 3]. However, Vitamin D intake was associated with hyperpigmentation (odds ratio [95% confidence interval]; 2.6 [1.17–5.80], P = 0.02).

DISCUSSION

LHR is a popular procedure worldwide for the reduction of unwanted hair. Different wavelengths are used for this purpose, and choosing the wavelength is dependent on multiple factors. One of the most important factors is the patient skin phototype. Competitive absorption of laser energy by the epidermal melanin increases the likelihood of pigmentary changes, especially in patients with darker skin types.[²] Therefore, using longer laser wavelength with relatively low fluences in addition to proper cooling might help minimize such complications.[¹] Vitamin D supplements might play a role in the development of hyperpigmentation post LHR.

Even if all precautions are taken, pigmentary changes cannot be avoided post LHR. Thus, the exploration of factors associated with post-LHR hyperpigmentation is important. Hyperpigmentation is considered a major cosmetic concern, especially in patients with darker skin types. In one prospective study of 480 patients who underwent LHR, the prevalence of postlaser hyperpigmentation was 2%.[²] Two factors were associated with more risk of hyperpigmentation, namely skin phototype and laser wavelength. Most of our patients had darker skin types (III and IV) with only a few who had very light skin types (I and II). Accordingly, we could not make a comparison between those with very fair skin and those with darker skin due to the small sample size. The majority of our patients were treated with LP 755-nm laser. A lack of difference in the prevalence of hyperpigmentation when compared to other lasers might be attributed to the smaller sample treated with other lasers.

In our study, males were less likely to have post-LHR hyperpigmentation. This can be explained partially by the documented role of estrogen in activating melanocytes and triggering or worsening melasma.[⁶⁷]

Vitamin D supplements were associated with hyperpigmentation post LHR. Vitamin D affects melanogenesis. Both Vitamin D2 (ergocalciferol) and D3 (cholecalciferol) stimulate melanogenesis in vitro.[⁸⁹] Cocultured with melanoma cells for 4 days, calciferols were associated with increased melanin content and tyrosinase activity.[⁸] However, ergosterol and 7-dehydrocholesterol (precursors of ergocalciferol and cholecalciferol) had little effect on tyrosinase activity.[⁸] In addition, cholecalciferol increased the dendricity of melanocytes.[⁹] Calcitriol (1,25-dihydroxyvitamin D3) induced the differentiation of murine immature melanocyte precursors.[¹⁰] Specifically, some cells became positive for tyrosinase, 3,4-dihydroxyphenylalanine, and endothelin B receptor after treatment with calcitriol for 3 days. Ultrastructural examination showed more accumulation of Stages III–IV melanosomes post calcitriol treatment.[¹⁰]

Our study has several limitations. Those include recall bias which is part of the issues of a retrospective cross-sectional design. Furthermore, patients were most probably taking different forms of Vitamin D and this was not documented in our study. In addition, it was not clear why these patients were taking Vitamin D and their Vitamin D level was not measured. Hyperpigmentation was not objectively determined in our study population. Finally, most of our patients were of skin types III and IV, so the results cannot be generalized to all skin types.

CONCLUSION

In conclusion, taking oral Vitamin D is associated with more post-LHR hyperpigmentation. Whether this relationship is causal is not clear.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

REFERENCES