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Laser Hair Removal

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Last Update: February 17, 2021.

Continuing Education Activity

The demand for safe, long-lasting, and effective hair reduction for aesthetic as well as medical indications is on the rise. A variety of options for hair removal are available, such as epilation by plucking or waxing, depilation by shaving, chemical depilatories, electrolysis, eflornithine cream, and laser and intense pulsed light (IPL) systems. A variety of lasers and IPL systems are available and are the best option for long-term hair reduction. This activity describes the different lasers, their indications, contraindications and complications and highlights the role of the interprofessional team in educating patients who want to undergo hair removal.

Objectives:

  • Describe the different lasers used for hair removal.
  • Review the indications for laser hair removal.
  • Summarize the complications of laser hair removal.
  • Outline interprofessional team strategies for improving care coordination and communication to advance care bundle approaches for hair removal with the laser and improving outcomes.
Earn continuing education credits (CME/CE) on this topic.

Introduction

The demand for safe, long-lasting, and effective hair reduction for aesthetic as well as medical indications is on the rise. A variety of options for hair removal are available, such as epilation by plucking or waxing, depilation by shaving, chemical depilatories, electrolysis, eflornithine cream, and laser and intense pulsed light (IPL) systems. A variety of lasers and IPL systems are available and are the most effective options for long-term hair reduction.[1] The mechanism of action of these systems is the targeting melanin in the hair shaft, follicular epithelium, and hair matrix by emitting light with wavelengths ranging from 600 to 1200 nanometers (nm), because those wavelengths are selectively absorbed by melanin.[2]

Anatomy and Physiology

Selective Photothermolysis

Lasers for skin treatment work on the theory of "selective photothermolysis." This term implies a site-specific, thermally mediated injury of microscopic tissue targets by the selective absorption of pulses of radiation by the targets and the chromophores. The natural or artificial chromophores absorb monochromatic or broadband electromagnetic radiation of specific wavelengths. The chromophore employed in laser hair reduction is melanin. Melanin absorbs light in the range of 300 to 1200 nm, and lasers in this range of wavelengths can be effectively used for hair reduction.[3][4]

An Extended Theory of Selective Photothermolysis

Target absorption may not always be uniform. In these cases, the weakly absorbing parts may have to be destroyed by heat diffusion from the highly absorbing parts. This is the "extended theory of selective photothermolysis." This principle is applied to laser photoablation. Melanin content is much higher in melanin-bearing structures like the hair shaft and matrix cells than in the hair follicle. Thus melanin captures energy from the laser and distributes it to the surrounding follicular structures. This results in the destruction of the hair matrix and hair bulge stem cells.[5]

Indications

  1. Hirsutism and hypertrichosis
  2. Aesthetic purposes
  3. Medical indications like pseudofolliculitis barbae, pilonidal sinus, and acne keloidalis nuchae.[6]

Equipment

Lasers for hair reduction include the following:

  1. Ruby Laser (694 nm) - Red light is delivered through synthetic ruby crystals, more effective for lighter skin types with dark hair (skin types I-III*)[7]
  2. Alexandrite Laser (755 nm) - Greater penetrance, good for lighter hair (skin types I-III)[8]
  3. Diode Laser (810 nm) - Penetrates deeper, delivers better fluence, less epidermal damage, safer in darker skin (skin types I-V)[9]
  4. Neodymium-doped Yttrium-Aluminium-Garnet (Nd: YAG) Laser (1064 nm) - Better penetration, less epidermal damage, relatively less melanin absorption (skin types I-VI)[10]
  5. Intense Pulse Light (IPL) or Broadband Light (BBL) (500-1200 nm) - High-intensity pulses of polychromatic, non-coherent light are delivered by a flash-lamp; various filters allow the narrowing of the emitted wavelength band, can be used on darker skin, larger areas can be covered due to its larger spot size, less expensive than a true laser but not as effective[11][12][13]

* Fitzpatrick Skin Types[10]

  • I- Pale white skin, blue/green eyes, blond/red hair; always burns, does not tan
  • II- Fair skin, blue eyes; burns easily, tans poorly
  • III- Darker white skin; tans after the initial burn
  • IV- Light brown skin; burns minimally, tans easily
  • V- Brown skin; rarely burns, tans darkly easily
  • VI- Dark brown or black skin; never burns, always tans darkly

Preparation

  1. Detailed clinical history to rule out infections, drug intake, etc.
  2. Hormonal evaluation to assess causes of hirsutism.
  3. Counsel the patient to manage expectations. It must be stressed that the procedure provides permanent hair reduction rather than removal.
  4. Evaluate skin and hair types to choose the right laser and parameters.
  5. Avoid hair epilation by plucking or waxing for 6 weeks before the procedure.
  6. Sunscreens may be prescribed 4 to 6 weeks before the procedure, especially on exposed areas.
  7. Pre-procedure photographs, with due consent, to maintain a record for evaluation of treatment response.
  8. Shave the area long enough before the procedure to allow a slight stubble to develop; this will provide enough of a target for the laser without absorbing too much energy in the hair shaft itself.
  9. Obtain an informed consent.
  10. If need be, a topical anesthetic cream may be applied one-half to one hour before the procedure.[14][15]

Technique

  1. Clean the area to remove oils from the skin
  2. Position the patient comfortably.
  3. Use eye protection for both the operator and the patient.
  4. Avoid reflecting surfaces or metallic objects near the laser.
  5. Individualize the parameters to each patient's skin and hair type and the type of laser being used. 
  6. Place the handpiece perpendicular to the skin. Ensure that it is pressed down gently but firmly to bring the follicles close to the surface and temporarily decrease the blood supply to the treatment area.
  7. Perifollicular edema and erythema is an expected side effect, and this must be explained to the patient prior to the procedure.[14][15]

Post-Procedure Care

  1. Although most machines have inbuilt cooling systems, ice packs or cooling agents may be used post-procedure to minimize pain and swelling.
  2. In case of inadvertent epidermal injury, topical antibiotics may be used.
  3. Strict sun protection and the use of sunscreens is a must.
  4. Topical steroid creams may be prescribed to minimize erythema and swelling.[14][11]

The hair matrix is only sensitive to laser treatment during the anagen phase of the hair growth cycle; therefore multiple treatments will be necessary in order to address all hair follicles when they are most sensitive to treatment. In the initial phase of hair removal therapy, 4 to 6 sessions spaced 4 to 6 weeks apart are the minimum required to achieve adequate results. Subsequently, patients may need maintenance treatments once every 6 to 12 months as small vellus hair may grow back.[16]

Various factors may affect the outcome, such as:

  1. Hair location (axillary and pubic hair respond better than hair on the extremities and chest)
  2. Skin and hair color (light skin of Fitzpatrick skin types I-IV with dark hair achieve the best results due to the lack of melanin in the skin and the abundance of melanin to absorb laser energy in the hair follicles)
  3. Hair growth stage (anagen hair being most sensitive)
  4. Laser type
  5. Hormonal status
  6. Treatment plan[2]

Complications

Adjacent epidermal structures other than melanin within the hair bulb can compete for absorption, and may cause laser energy to be absorbed by pigment in the epidermis. This hampers the effectiveness of the treatment and causes adverse effects due to adjacent epithelial damage. [17]

Common adverse effects of laser or IPL-based hair removal include post-treatment erythema, pain, and burning.[18]

More severe adverse effects include blistering, crusting, dyspigmentation, purpura, and sometimes scarring.[19][20] Ocular complications due to accidental injury may be seen. Paradoxical hypertrichosis may rarely occur, more commonly in skin type III and with the use of IPL systems.[21][22][23]

Clinical Significance

Selecting the correct lasers with the appropriate parameters, individualized to each patient, is very important, particularly in patients with intrinsically dark skin. Most complications are preventable when adequate precautions are taken with adjustment of the fluence, spot size, wavelength, and the use of appropriate cooling. Thus, it is all the more important that trained personnel with a thorough knowledge of the mechanisms, techniques, and complications carry out these procedures.

Enhancing Healthcare Team Outcomes

Laser hair removal is performed by many healthcare workers including nurses, dermatologists, plastic surgeons, primary care providers and other cosmetic surgeons. Unfortunately, because of lack of oversight, complications are common during this procedure. To make matters worse, patients are often given unrealistic expectations. The key is to use the correct laser, especially in dark skinned individuals. Common adverse effects of laser or IPL-based hair removal include post-treatment erythema, pain, and burning.[18] More severe adverse effects include blistering, crusting, dyspigmentation, purpura, and sometimes, scarring.[19][20] Ocular complications due to accidental injury may be seen. Paradoxical hypertrichosis may rarely occur, more commonly in skin type III and with the use of IPL systems.[21][22][23]

Overall, lasers can remove hair but rarely does the procedure provide a permanent cure for hair growth. Touch up maintenance treatments are required for most patients in the long term.

Continuing Education / Review Questions

References

1.
Haedersdal M, Wulf HC. Evidence-based review of hair removal using lasers and light sources. J Eur Acad Dermatol Venereol. 2006 Jan;20(1):9-20. [PubMed: 16405602]
2.
McDaniel DH, Lord J, Ash K, Newman J, Zukowski M. Laser hair removal: a review and report on the use of the long-pulsed alexandrite laser for hair reduction of the upper lip, leg, back, and bikini region. Dermatol Surg. 1999 Jun;25(6):425-30. [PubMed: 10469087]
3.
Anderson RR, Parrish JA. Selective photothermolysis: precise microsurgery by selective absorption of pulsed radiation. Science. 1983 Apr 29;220(4596):524-7. [PubMed: 6836297]
4.
Lask G, Elman M, Slatkine M, Waldman A, Rozenberg Z. Laser-assisted hair removal by selective photothermolysis. Preliminary results. Dermatol Surg. 1997 Sep;23(9):737-9. [PubMed: 9311365]
5.
Altshuler GB, Anderson RR, Manstein D, Zenzie HH, Smirnov MZ. Extended theory of selective photothermolysis. Lasers Surg Med. 2001;29(5):416-32. [PubMed: 11891730]
6.
Goldberg DJ. Laser hair removal. Dermatol Clin. 2002 Jul;20(3):561-7. [PubMed: 12170888]
7.
Dierickx CC, Grossman MC, Farinelli WA, Anderson RR. Permanent hair removal by normal-mode ruby laser. Arch Dermatol. 1998 Jul;134(7):837-42. [PubMed: 9681347]
8.
Garcia C, Alamoudi H, Nakib M, Zimmo S. Alexandrite laser hair removal is safe for Fitzpatrick skin types IV-VI. Dermatol Surg. 2000 Feb;26(2):130-4. [PubMed: 10691941]
9.
Lou WW, Quintana AT, Geronemus RG, Grossman MC. Prospective study of hair reduction by diode laser (800 nm) with long-term follow-up. Dermatol Surg. 2000 May;26(5):428-32. [PubMed: 10816229]
10.
Chan CS, Dover JS. Nd:YAG laser hair removal in Fitzpatrick skin types IV to VI. J Drugs Dermatol. 2013 Mar;12(3):366-7. [PubMed: 23545924]
11.
Weiss RA, Weiss MA, Marwaha S, Harrington AC. Hair removal with a non-coherent filtered flashlamp intense pulsed light source. Lasers Surg Med. 1999;24(2):128-32. [PubMed: 10100650]
12.
Tse Y. Hair removal using a pulsed-intense light source. Dermatol Clin. 1999 Apr;17(2):373-85, ix. [PubMed: 10327304]
13.
Sadick NS, Weiss RA, Shea CR, Nagel H, Nicholson J, Prieto VG. Long-term photoepilation using a broad-spectrum intense pulsed light source. Arch Dermatol. 2000 Nov;136(11):1336-40. [PubMed: 11074695]
14.
Nanni CA, Alster TS. A practical review of laser-assisted hair removal using the Q-switched Nd:YAG, long-pulsed ruby, and long-pulsed alexandrite lasers. Dermatol Surg. 1998 Dec;24(12):1399-405; discussion 1405. [PubMed: 9865211]
15.
Tanzi EL, Lupton JR, Alster TS. Lasers in dermatology: four decades of progress. J Am Acad Dermatol. 2003 Jul;49(1):1-31; quiz 31-4. [PubMed: 12833005]
16.
Grossman MC, Dierickx C, Farinelli W, Flotte T, Anderson RR. Damage to hair follicles by normal-mode ruby laser pulses. J Am Acad Dermatol. 1996 Dec;35(6):889-94. [PubMed: 8959946]
17.
McBurney EI. Side effects and complications of laser therapy. Dermatol Clin. 2002 Jan;20(1):165-76. [PubMed: 11859590]
18.
Dierickx CC. Hair removal by lasers and intense pulsed light sources. Dermatol Clin. 2002 Jan;20(1):135-46. [PubMed: 11859588]
19.
Nanni CA, Alster TS. Laser-assisted hair removal: side effects of Q-switched Nd:YAG, long-pulsed ruby, and alexandrite lasers. J Am Acad Dermatol. 1999 Aug;41(2 Pt 1):165-71. [PubMed: 10426883]
20.
Lapidoth M, Shafirstein G, Ben Amitai D, Hodak E, Waner M, David M. Reticulate erythema following diode laser-assisted hair removal: a new side effect of a common procedure. J Am Acad Dermatol. 2004 Nov;51(5):774-7. [PubMed: 15523357]
21.
Hussain M, Polnikorn N, Goldberg DJ. Laser-assisted hair removal in Asian skin: efficacy, complications, and the effect of single versus multiple treatments. Dermatol Surg. 2003 Mar;29(3):249-54. [PubMed: 12614418]
22.
Battle EF, Hobbs LM. Laser therapy on darker ethnic skin. Dermatol Clin. 2003 Oct;21(4):713-23. [PubMed: 14717412]
23.
Alajlan A, Shapiro J, Rivers JK, MacDonald N, Wiggin J, Lui H. Paradoxical hypertrichosis after laser epilation. J Am Acad Dermatol. 2005 Jul;53(1):85-8. [PubMed: 15965427]
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Bookshelf ID: NBK507861PMID: 29939638

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