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A. Tosti et al. (eds.)Hair and Scalp Treatmentshttps://doi.org/10.1007/978-3-030-21555-2_5

5. Laser and Light-Based Therapies in the Treatment of Hair Loss

Rachel Fayne¹, Nelson Sanchez¹ and Antonella Tosti²

(1)

Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL, USA

(2)

Fredric Brandt Endowed Professor of Dermatology, Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL, USA

Nelson Sanchez

Email: nsanchez@med.miami.edu

Keywords

Low-level light therapyFractional laserErbium-glass laserThallium laserCO₂ laserExcimer laserPulsed laser

Introduction

Laser and light-based therapies including low-level laser and light therapy fractional, excimer, and other lasers are increasingly well-regarded treatment options for patients with hair loss.

Lasers emit wavelengths of light specific to a chromophore in the tissue, causing a targeted thermal response with minimal damage to the surrounding tissue [1]. The cascade of events downstream of the initial injury is responsible for the clinical effects seen. Low-level laser or light therapy was accidentally discovered in the 1960s when Hungarian scientist Endre Mester attempted to repeat an experiment performed by American Paul McGuff, who had cured malignant tumors in rats using a ruby laser [2]. Mester’s laser was much less powerful than McGuff’s, and while he did not successfully cure any tumors, he observed for the first time that a low-level laser induced hair growth and improved wound healing. The mechanism by which this occurs is described as photobiomodulation or the stimulation of biological processes in the target tissue [3]. This accidental discovery is the basis for the huge variety of LLLT products available on the market today.

In the last 2 years alone, the number of approved items classified as laser, comb, or hair products intended for the purpose of the growth of scalp hairs on the FDA’s 510(k) premarket notification list, meaning the device is demonstrated to be at least safe and effective, has nearly doubled to a total of 50. This chapter will summarize current knowledge regarding all laser and light devices for patients with various forms of alopecia and will outline treatment strategy, device parameters, and appropriate limitations of use to guide providers toward optimal patient management.

Diagnosis and Pretreatment Considerations

The device to be utilized depends on the type of alopecia. For patients with androgenetic alopecia, options include LLLT and fractional laser. Patients with alopecia areata may benefit from use of excimer or fractional lasers. For patients with lichen planopilaris or its variants including frontal fibrosing alopecia (FFA), there is evidence for excimer laser, but LLLT is in development (Table 5.1).

Table 5.1

Summary of devices used for common hair loss disorders

Device	Treatment schedule
Androgenetic alopecia
Erbium-glass laser	Use for 5–12 sessions with approximately 2 weeks in between sessions [5, 6]
Thulium laser	Use for 12 sessions with 1 week in between sessions Study with concurrent use of topical growth factor serum [12]
Comb devices (HairMax^® LaserComb, NutraStim Laser Hair Comb, HairMax^® LaserBand)	Use for 8–15 minutes 3 times per week [24–27]
Cap/Helmet devices (iRestore Laser Hair Growth System, Thermadome Hair Growth Helmet, Capillus Pro Laser Cap, iGrow laser helmet, Oaze Hair Beam)	Use for 6–30 minutes every day or every other day [28–33]
Office devices (“Cold” X5 HairLaser, Apira Science Revage 670, Sunetics International laser, Capillus Office Pro)	“Cold” X5: use for 15 minutes for up to 26 weeks [34] Sunetics International, Apira Science Revage: use for 20 minutes 2 times per week for up to 6 months If additional treatments are needed, use for 20 minutes 2 times per month for an additional 6 months [35]
Alopecia areata
Erbium-glass laser	Use every 2–3 weeks for approximately 3–6 months [8, 9, 11]
CO₂ laser	Use for 1–6 sessions with 2- to 4-week intervals [15, 16]
Excimer laser	Use 2 times per week for at least 12 weeks [39–46]
Pulsed devices (The Super Lizer™, Pulsed Diode)	Super Lizer™: use for 3 minutes every 1–2 weeks for up to 5 months [49] Pulsed Diode: use 1 time per week for 1 month [50]
Lichen planopilaris
Excimer laser LLLT devices	Use 2 times per week for up to 16 sessions [47, 48] Use 3 times per week
Frontal fibrosing alopecia
Excimer laser	Use 2 times per week for up to 16 sessions [47, 48]

Patients with a low threshold for pain may benefit from the use of a topical anesthetic prior to fractional laser treatment. Many devices have built-in or optional cooling sprays that are administered simultaneously with each pulse to improve patient comfort. Application of ice or cooling packs to the skin after treatment may help patients feel more comfortable and reduce post-inflammatory changes.

In patients with a previous history of herpes virus infection, prophylactic antiviral therapy should be used before, during, and after the fractional laser treatment.

Laser therapy is commonly utilized in association with other treatments for alopecia, including topical minoxidil, 5-alpha reductase inhibitors, and topical/intralesional steroids.

Fractional Lasers

Introduction

Conventionally, fractional lasers are used in the treatment of atrophic scars and skin resurfacing to minimize enlarged pores and reverse effects of photoaging. However, a number of pilot studies have begun to examine the role of fractional lasers, including erbium-glass, thallium, and CO₂ lasers, in the treatment of alopecia. Each operates with different energy settings and thus requires a different protocol for optimal results. Evidence of efficacy is still poor.

Mechanism of Action

Fractional lasers utilize fractional thermolysis (FT), a slightly different mechanism of action than traditional laser technology. FT induces thermal injury to targeted skin in a pattern characterized by skip areas and repetition to minimize adverse effects [4]. While the precise mechanism by which FT induces hair growth is unknown, it is proposed to be related to dermal remodeling. After thermal injury from the laser, dermal tissue experiences increased blood flow with induction of cytokines and expression of growth factors, including TGFB and IGF1, to promote hair growth [5, 6]. Additionally, upregulation of signaling via increased molecular levels of Wnt and β-catenin after laser treatment is thought to enhance the transition of hairs from telogen to anagen phase of the hair growth cycle, further promoting hair growth [7].

Devices, Energy Settings, Treatment Protocols (Table 5.2)

Erbium-Glass Laser

The 1550 nm erbium-glass laser provides significant results when used with a low-energy approach of 5–15 mJ [5, 6, 8–11]. Low-energy is preferable to avoid excess breakage of the hair shaft. These lasers should not be used too frequently (>2 times per week), as this may induce fibrous changes around the hair follicle that could prevent future growth [5]. Optimal treatment interval appears to be approximately 2 weeks between sessions [5, 6, 8].

Table 5.2

Summary of studies using fractional lasers for the treatment of alopecia

Study	Subjects	Wavelength (nm)	Energy (mJ)	Density (spots/cm²)	Total sessions	Treatment interval (weeks)	Results	Follow-up (month)	Adverse effects^a
Erbium-glass
Kim et al. [5] (pilot study)	MPHL (n = 20)	1550	5	300	5	2	Increased hair density; increased hair growth rate; increased anagen:telogen ratio	1	Breakage of hair shaft, damage to cuticles and cortex, transient shedding
Meephansan et al. [6] (prospective, nonrandomized)	MPHL, FPHL (n = 23)	1550	6	300	12	2	Increased hair density, hair shaft diameter; increased terminal hair count; reduced vellus/nonvellus hair ratio	5	None reported
Lee et al. [8] (prospective, nonrandomized)	AA (n = 28)	1550	6	800	10	2	Increased hair density; increased hair thickness	5	Transient pruritus
Eckert et al. [9] (case series)	AA (n = 5)	1550	6–8	Not reported	2–3	3–6	Increased visual global improvement score; full to almost-full regrowth within 3 months	24–48	None reported
Cho et al. [10] (case series)	Various (n = 17)	1550	6–8	300	8–22	Not reported	Hair growth noted in 70.6% of all study participants	2	None reported
Yoo et al. [11] (case report)	AA (n = 1)	Not reported	10–15	300	24	1	Complete regrowth after 6 months of treatment without recurrence	6	None reported
Thallium
Cho et al. [12] (blinded, controlled mouse model)	MPHL (n = 10)	1927	4–6	Not reported	12	1	Increased hair count; increased hair thickness	3	None reported
CO ₂
Cho et al. [10] (case series)	Various (n = 17)	10,600	30–50	150	8–22	Not reported	Hair growth noted in 70.6% of all study participants; terminal hair regrowth; hair thickening	2	None reported
Bae et al. [14] (mouse model)	C57BL/6 mice (n = 6)	10,600	10–30	100–300	1	Not applicable	Increased proportion of hairs in the anagen phase; various degrees of hair regrowth seen	Not applicable	Scar tissue formation with excess energy and density
Yalici et al. [15] (prospective, controlled)	AA (n = 32)	30 W	10–45	75–100	3–6	2–4	No increase in mean hair count as compared to controls	1	None reported
Issa et al. [16] (prospective, nonrandomized)	AA (n = 3)	60 W	60 mJ/pixel	Not reported	1–6	3	Clinical improvement seen within 1 month after 1 treatment	12	None reported

^aAdverse effects universal to all laser and light-based therapies (i.e., transient pain, pruritus, or erythema) are not recorded in this table

Patients with androgenetic alopecia may require continuous use of the laser to prevent eventual decrease in hair density, which can be seen as early as 4 months after discontinuation of treatment [5]. Patients with alopecia areata may require fewer treatments without long-term use to achieve full regrowth of bald patches [9, 11].

Thulium laser

The fractionated thulium laser operates with a wavelength of 1927 nm. This laser shows clinical efficacy when used at a low-energy setting of 4–6 mJ 1 time per week over 12 weeks. A decrease in hair count may be seen months after stopping treatment, so continuous use may be necessary to maximize results for patients with pattern hair loss [12].

This device has also been studied in laser-assisted hair restoration therapy in association with intraperifollicular injections of polydeoxyribonucleotide (PDRN). [13]

CO₂ Laser

The ablative CO₂ laser emits light with wavelength of 10,600 nm, allowing for use of higher energies, ranging from 10 to 50 mJ, with lower densities of 100–300 spots/cm². After one treatment session, hair growth may be observed, but this laser is safe for repeated use with up to 22 sessions [10, 14]. Other CO₂ lasers measure power in watts. Higher power is more often associated with pain, which can be intolerable for patients. Using a power setting as low as 30 W does not yield significant clinical results, but the use of a topical anesthetic may allow an increase in power that is tolerable [15]. With power of 60 W, a clinical improvement can be noted after 1–6 treatments at 3-week intervals [16].

Adverse Effects

Mild pain is reported almost universally with fractional lasers in the treatment of alopecia. Transient erythema, crusting, and pruritus have also been reported. More severe, long-lasting effects are often a result of using higher energy settings. With the erbium-glass laser, higher energy settings may cause breakage to the hair shaft and damage to the hair cuticle and cortex. Care should be taken not to exceed approximately 5–15 mJ unless additional protective measures are undertaken [5]. Similarly, when using the ablative CO₂ laser, do not use an energy >10 mJ/spot with a density of 300 spots/cm², as this may lead to decreased potential for future hair growth due to scar tissue formation [10]. Prophylaxis is recommended in patients with a history of herpes infections.

LLLT

Introduction

LLLT has been extensively studied and shown to provide significant clinical results as both an individual therapy and an adjuvant to traditional therapies like minoxidil and finasteride for patients with androgenetic alopecia [17]. LLLT is safe, easy to use, and widely accessible and thus may provide a satisfactory alternative for patients dissatisfied with other therapeutic options.

Mechanism of Action

While the precise mechanism of action by which LLLT affects hair growth remains unknown, a number of proposed theories have been developed. LLLT may accelerate cell turnover by generating reactive oxygen species and various antioxidants, creating an environment that supports hair growth [18]. It may also have an activating effect on mitochondria, thus increasing cell metabolism and hair growth [19, 20]. It has also been shown that, subsequent to treatment with LLLT, there is decreased local inflammation, which may allow for increased hair growth [21–23]. Preliminary data and author’s personal experience indicate that LLLT treatment can be helpful in case of AGA associated with inflammatory scalp disorders and even to reduce inflammatory changes in lichen planopilaris and other types of scarring alopecias (Figs. 5.1 and 5.2) [24].

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