Laser Hair Removal 

Updated: Sep 25, 2017
Author: Mounir Bashour, MD, PhD, CM, FRCSC, FACS; Chief Editor: Arlen D Meyers, MD, MBA 

Overview

Background

Success in laser hair removal is typically reported in terms of permanent hair elimination or in terms of marked delay in its growth. Most investigators have assessed patients with light skin types (ie, Fitzpatrick skin types I-III), but more recent groups have studied newer lasers for Fitzpatrick skin types IV-VI.

See the image below.

Anatomy of the hair follicle. Anatomy of the hair follicle.

History of the Procedure

Goldman et al first described ruby-laser injury to pigmented hair follicles in 1963.[1] In 1983, Oshiro and Maruyama noted hair loss from nevi after treatment with a ruby laser.[2] However, at fluences affecting hair follicles, the epidermis was severely damaged.

The theory of selective photothermolysis that Anderson and Parrish developed in 1983 was based on a laser of particular wavelength and a pulse duration of light to target a particular chromophore.[3] By applying this theory, the target can be destroyed selectively, sparing the surrounding tissue.

Use of a topical suspension of carbon particles followed by treatment with a Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) laser was the first laser treatment for hair removal the US Food and Drug Administration (FDA) approved. This initial method reportedly delayed regrowth by 3 months, but it did not provide permanent hair reduction.

In 1996, Grossman and associates, who used a normal-mode ruby laser, reported the first application of Anderson and Parrish's theory for hair removal.[4] In 1998, Dierickx and associates published their report of a 2-year follow-up study demonstrating long-term, permanent hair removal with this laser.[5]

Hair-removing lasers and light sources

Since then, the market has been flooded with numerous hair-removing lasers and light sources.[6]

Initial laser systems, such as the Q-switched Nd:YAG (1064 nm, Soft Light system; Thermolase Corp, San Diego, CA), used a suspension of carbon mineral oil to penetrate the hair follicle and to act as an energy-absorbing chromophore.

An optically filtered xenon flashlamp (Epi Light, ESC Luxar; Energy Systems Corp, Needham, MA) uses filters to select operating wavelengths of light at a cutoff of 690 nm, allowing light above this wavelength to pass through to affect hair.

The long-pulse ruby laser (EpiLaser 694 nm, Palomar Technologies, Lexington, MA; EpiTouch, Sharplan Laser, Allendale, NJ) uses the principle of selective thermolysis in which melanin acts as the target chromophore.

The long-pulse alexandrite laser (PhotoGenica LPIR 755 nm; Cynosure Inc, Chelmsford, MA) is based on the principle of thermokinetic selectivity and targets melanin in the hair follicle. In this way, the epidermis is allowed to cool efficiently while the melanin in the hair follicle is heated.[7, 8]

Coherent Medical (Santa Clara, CA) and Palomar (Lexington, MA) have introduced the LightSheer, a diode laser operating at 800 nm that has pulse durations of as long as 30 ms. This technology minimizes the size of the laser by replacing the laser tube in place of solid-state diode circuitry.[9]

Most technical improvements in laser devices have been incremental in terms of improving efficacy and reducing side effects. Some new models combine light- and heat-based methods by using radio-frequency (RF) energy; these are based on the theory that the heated areas can be further heated without causing damage to surrounding skin.

New devices are frequently introduced, and old models may be discontinued but still available as after-market products. Check with the manufacturers for latest information.

Home-use lasers and IPL devices

Several low-power devices have been marketed directly to consumers as home-use epilators. Originally, most were not capable of even epilation. More recently, the FDA has approved some devices for in-home use. Physicians should ascertain whether patients presenting with adverse effects were using one of these devices instead of medical-grade lasers.[10, 11]

Problem

Unwanted pigmented hair is a common cosmetic problem for both men and women.

Epidemiology

Frequency

About 4% of young, healthy randomly selected white women feel disfigured by their facial hair. The percentage is even higher in people of color and increases with age. This percentage does not reflect the vast number of patients who have unwanted hair in other areas, and it does not account for the huge number of men who feel disfigured by unwanted hair (eg, on the ears and back).

Etiology

Excessive hair growth affects the healthy population, but it also severely affects patients with hormonal disturbances, such as polycystic ovary disease, congenital adrenal hyperplasia, hirsutism, hypertrichosis, and congenital hairy nevi.

Excessive hair growth has been implicated in the pathogenesis of pilonidal disease and in the unfavorable outcome of some reconstructive flaps.

Pathophysiology

Hirsutism is characterized by the excessive growth of coarse terminal hairs in women in a pattern similar to that of adult men. Given the subjectiveness of this perception, especially in different racial groups, Ferriman and Galway developed a scoring scale. Nine body areas are used to grade hair growth on a scale of 0-4. The scores for the 9 body parts are added, and a total score of 8 or more defines hirsutism. On the basis of this scale, 5% of women in the United States have hirsutism.

Hyperandrogenism (ie, increased plasma androgen levels) is sometimes the cause. This condition may be related to adrenal causes (eg, congenital adrenal hyperplasia, androgen-producing tumors), pituitary causes (eg, Cushing disease), ovarian causes (eg, polycystic ovary disease, ovarian tumors), or exogenous causes (eg, anabolic steroids, testosterone).

Idiopathic hirsutism is likely caused by subtle forms of ovarian or adrenal hypersecretion, alterations in serum androgen-binding proteins or androgen metabolism, or (most likely) excessive genetic sensitivity of hair follicles to normal androgen levels.

Presentation

Patients typically have a history of either excessive hair growth or hair growth in undesired body locations. For men, these areas are often the shoulders, back, and ears. For women, these areas are often the face, breasts, legs, and lower abdomen.

Take a complete history, including menstrual, pregnancy, and family histories. Discuss the degree of past, recent, and potential future sun exposure.

Perform a full external physical examination. If a hormonal problem is suspected, consider referring the patient to an endocrinologist or a gynecologist.

Indications

The indication for hair removal is mostly subjective. A desire for hair removal is the only criterion for laser surgery.

Relevant Anatomy

Each hair has 3 distinct components: the bulb, which lies near the insertion of the erector pili, the isthmus, and the infundibulum.

Pluripotential cells in the bulb and bulge areas cause growth of the hair follicle. Melanocytes are present in these areas. For most people, the bulb is approximately 4 mm beneath the surface of the skin (deeper in some individuals). Therefore, a considerable laser-penetration depth is required to remove the bulb.

Hair grows in cycles. Anagen is the active growth phase, catagen is the transition phase, and telogen is the resting phase. The duration of the anagen phase governs the length of hair at different body sites. Lasers are truly effective in only the anagen phase, when hair-matrix cells divide rapidly and migrate outward from the shaft and when the melanin load is at its highest. During the catagen phase, mitosis ceases, the hair matrix regresses, the papilla retracts to a place near the bulge, and capillary nourishment diminishes. In the telogen phase, the follicle detaches from the papillae and contracts to a third of its original depth, eventually falling out. The telogen phase varies in duration from one body area to the next. For example, the telogen phase may last as long as a year for hair on the leg.

The ratio of anagen follicles to telogen follicles varies with body location. Because not all of the hairs are in the anagen phase at any 1 time, laser treatment must be repeated to capture the new hairs coming into the anagen phase.

Contraindications

For the laser to be effective, the hair pigment must be darker than the surrounding skin pigment. If this is not the case, the treatment will not work, and harmful complications may occur. Early in the evolution of the procedure, patients with Fitzpatrick skin types V or VI were not candidates, and even patients with skin types III and IV were at high risk. With new technologies, most patients can now be treated, though caution must still be exercised.

Recently, Aldraibi et al looked at using topical corticosteroid treatment to help minimize the side effects when treating skin types IV-VI with an Alexandrite laser system.[12] Their study showed that using a topical corticosteroid treatment appears to minimally help in reducing posttreatment erythema and edema and also decreases the duration of hyperpigmentation. It was felt in this study that treating skin type VI was "less safe."

A literature review by Fayne et al suggested that Fitzpatrick skin types IV-VI can undergo safe and effective laser hair reduction using longer wavelengths and employing Nd:YAG, diode, alexandrite, or ruby lasers. Some intense pulsed light sources were also found to be useful.[13]

Sun tanning is obviously contraindicated during or before treatment because the practice darkens the pigment of the skin surrounding the hair.

 

Workup

Other Tests

See the list below:

  • Do not forego skin patch testing, the most important step in laser hair removal. The results of skin patch testing determine the settings for the laser and the safety profile.

  • Perform testing in a low-visibility area with the same skin type as the area intended for treatment. If possible, allow at least 3 days before reexamining the site to assess for efficacy and for a reaction.

  • If sufficient energy is delivered and absorbed, a generalized hyperemia reaction with mild focal swelling is visible after 3-5 minutes.

    • Increase the fluence for the particular skin type, and note the patient's pain reaction until the hyperemia reaction is observed.

    • For light or thin hair, the reaction may be minimal even at high settings.

  • Note the laser setting for each type of treated area.

 

Treatment

Medical Therapy

Alternative treatments for hair removal or concealment are available and include waxing or sugaring, electrolysis, bleaching, depilation, shaving, tweezing, and application of eflornithine hydrochloride cream (Vaniqa).

Vaniqa is a recently introduced topical cream that works for some women. The active ingredient is eflornithine hydrochloride, which inhibits an enzyme (ornithine decarboxylase) that affects hair growth. Unpublished efficacy data submitted to the FDA showed that about 58% of women using the cream on facial hair had an improvement. This observation suggests the cream may be particularly effective in postmenopausal women. Vaniqa is currently approved for use on only the face and chin in female adolescents and women older than 12 years. In theory, the agent can be used as an adjuvant to laser hair removal.

Surgical Therapy

Patients are ready for treatment after their skin type is categorized and after they have had a patch test. The treatment can be performed with or without topical anesthesia, depending on the patient's comfort level; however, see Cautions about topical anesthetics below. The pain response varies with the individual, with the area being treated (see the image below), and with the energy level of the treatment. Accordingly, anesthesia must be tailored to each patient.

Pain-sensitivity diagram. Pain-sensitivity diagram.

In the opinion of the present authors, the most effective and simplest anesthesia currently available is eutectic mixture of local anesthetics (EMLA) or ELA-Max topical anesthetic cream. Table 1 lists the most common anesthetics, their active ingredients, and their advantages and disadvantages.

Table 1. Advantages and Disadvantages of Anesthetics (Open Table in a new window)

Anesthetic

Active Ingredient

Advantages

Disadvantages

Ametop gel

Tetracaine 4%

  • Performed well in clinical trials

  • Requires no plastic covering

  • Has rapid onset

  • Must be applied generously

  • Not available in the United States

  • May become runny or sticky after application

Betacaine cream

Lidocaine, prilocaine

  • Requires no plastic covering

  • Has a rapid onset

  • Requires no prescription

  • Must be applied generously

  • May become runny or sticky after application

  • Can cause redness that lasts a few hours

  • Available only from manufacturer

ELA-Max or ELA-Max 5 cream

Lidocaine 4% or 5%, respectively

  • Performed well in clinical trials

  • Requires no plastic covering

  • Has a rapid onset

  • Requires no prescription

  • Widely available

  • Must be applied generously

  • May become runny or sticky after application

  • Can cause redness that lasts a few hours

EMLA cream

Lidocaine 2.5%,

prilocaine 2.5%

  • Performed well in clinical trials

  • Might be covered by insurance

  • Widely available

  • Must be applied generously

  • Must be covered with plastic

  • Has slow onset

  • Requires a prescription

  • May lose effectiveness once uncovered

  • Can cause skin whitening for a few hours

Mento-kaine liquid

Benzocaine 20%, phenol, camphor, menthol

  • Good before waxing

  • Inexpensive

  • Has a rapid onset

  • Does not penetrate as deeply or as well as creams or gels

  • Irritates sensitive skin

Stud spray

Lidocaine 9.6%

  • Good before waxing

  • Inexpensive

  • Has a rapid onset

  • Does not penetrate as deeply or as well as creams or gels

  • Small bottle

Preoperative Details

Patients are instructed not to pluck hairs for several weeks before treatment and not to sunbathe for several weeks or even months before treatment. Some lasers (eg, the CoolGlide laser) are reported to work even when patients sunbathe, but the procedure is less effective in people who sunbathe than in those who do not.

The area to be treated is shaved before anesthetic cream is applied. The cream is later removed, and the area is marked (an eye-makeup marker works best) and photographed. If a cooling gel is used, it is applied at this stage. If the handpiece offers dynamic cooling, it is firmly applied to the skin.

Cautions about topical anesthetics

At least 3 deaths have been linked to use of topical anesthetics in preparation for laser hair removal. Practitioners must educate patients about interactions between topical anesthetics and other pain medications, and both the practitioner and the patient must be aware of early symptoms of adverse reactions.

Intraoperative Details

The laser is applied to the target area at the fluence level predetermined by patch testing.

Postoperative Details

After treatment, most patients have a mild sunburn-type sensation that fades in 2-3 hours. Moisturizers and/or cool compresses can help during this time. Small blister areas can be treated with Bacitracin applied 3 times daily until they resolve.

Sunblock should be used for as long as 6 weeks after treatment if sun exposure is anticipated. No waxing, shaving, or dying should be performed for 2 weeks after treatment. Pretreatment restrictions also apply to the posttreatment period.

Ejection of hair shafts (ie, clearing out) occurs in the first 10-14 days. Some erythema and minor edema can persist for 2-3 days after facial treatment and longer in other areas (eg, 1 wk on the trunk). Treated sites should be washed with gentle soap (eg, Dove) and water twice a day.

Follow-up

Three treatments (range, 2-6 sessions) are usually needed to achieve the desired effects. The timing of treatments is important because hair should be treated during the anagen phase. This phase is short (6-12 wk) for hair on the head, and treatments are spaced a month apart. On the trunk, the telogen phase lasts 12-24 wk, and 2-month spacing is best.

Table 2. Distribution of Hairs in the Telogen and Anagen Phases and Growth Times (Open Table in a new window)

Location

Resting Hairs,

%

Growth Time

Telogen

Anagen

Telogen

Anagen

Head

Scalp

13

85

3-4 mo

2-6 y

Eyebrows

90

10

3 mo

4-8 wk

Ear

85

15

3 mo

4-8 wk

Cheeks

30-50

50-70

NA

NA

Beard or chin

30

70

10wk

1 y

Mustache or upper lip

35

65

6 wk

16 wk

Body

Axillae

70

30

3 mo

4 mo

Trunk

NA

NA

NA

NA

Pubic area

70

30

3 mo

4 mo

Arms

80

20

18 wk

13 wk

Thighs

80

20

24 wk

16 wk

Breasts

70

30

NA

NA

NA = not applicable.

*Adapted from Cutis. Mar 1990;45(3):199-202[14]

 

Complications

Hyperpigmentation is the most common effect and usually resolves within 6 months without treatment. The following complications are possible: itching during treatment; pain, tingling, or a feeling of numbness (with a cold spray); crusting or scab formation on ingrown hairs; bruising (rare); purpura on tanned areas; redness; swelling; infection (uncommon); and temporary hypopigmentation or hyperpigmentation; and scarring (which does not occur at proper fluences and with appropriate skin cooling).

Table 3. Reported Incidence of Adverse Events in Different Laser, Light, and Light/Heat Energy Systems on Skin Types IV-VI (Open Table in a new window)

Adverse event

Long-Pulsed

694 nm Ruby

Long-Pulsed

755 nm Alexandrite

Long-Pulsed

800 nm Diode

Long-Pulsed

810 nm Diode

Long-Pulsed

1064 Nd:YAG

IPL

IPL/

Heat Energy

Erythema

...

90%

69%

52%

23%

92%

54%

Burning

...

61%

30%

44%

14%

...

4%

Blistering/crusting

8%

...

...

5%

...

4%-12%

...

Hypopigmentation

4%

8%

5%

11%-25%

...

12%

8%

Hyperpigmentation

16%

40%

31%

9%-38%

2%

12%

8%

Other scarring

...

15%

6%

...

2%

...

...

* Adapted from J Drugs Dermatol. Jan 2007;6(1):40-6[15]

Laser hair removal has not been available long enough to permit a full assessment of its long-term health effects. At this time, short-term data indicate that laser hair removal is generally safe. Because studies have shown that laser hair removal can alter skin structures such as sweat and oil glands, they may cause lasting changes to the skin as adverse effects in some patients.

Based on over 1200 medical device reports (MDRs) concerning medical technology used in dermatology, as contained in the US Food and Drug Administration’s Manufacturer and User Facility Device Experience (MAUDE) database, Tremaine and Avram identified radiofrequency devices, diode lasers, and intense pulsed light devices to be the devices most frequently reported in association with injuries.[16]

Outcome and Prognosis

Outcomes vary, and any assurances of 100% effectiveness or 0% regrowth (often stated in marketing campaigns) should not be believed. Certain patients have a minimal response, whereas others have exceptional response. In addition, the treatment applied is often variable in the outcome.

Treatment at painless, low-energy levels produces a response that the present authors call laser waxing. This technique essentially induces the follicles to enter the telogen phase so that they grow back over time; however, they grow back exactly as they had been.

For permanent hair reduction, the laser must be applied to its limit for the particular patient and for the area being treated (as determined with careful patch testing). This requirement usually means a painful treatment and a need for local anesthesia. Only this method truly provides an opportunity for permanent follicular death. Any claims to the contrary should be viewed with suspicion.

Treatment as described provides gratifying and permanent results, and patients are often extremely pleased.

A study by Ormiga et al involving 21 female patients indicated that a diode laser and intense pulsed light (IPL) can both be used to achieve safe, effective long-term axillary hair removal. The diode laser was nonetheless found to be more effective than IPL, although it was also found to be more painful.[17]

Future and Controversies

Laser manufacturers will further refine their products, and other modalities (eg, oral or topical medical therapy) may eventually supplant laser hair removal. Until then, current laser treatment probably has reached its maturity, and the field lacks only long-term studies to prove the permanent efficacy of laser hair removal when it is properly applied.

In 2007, Sand et al published a paper that studied the use of sprayed-on liposomal melanin (Lipoxome; Dalton Medicare B.V., Zevenbergschen Hoek, The Netherlands) to allow removal of blond/white and gray hair with a diode laser.[18] Their study found a very mild increase in the removal of such hairs after 6 months, but "the clinically observed hair reduction was so weak that additional effort as well as higher costs argues against the application of the tested formulation."

A study by Chuang et al suggested that the burning-hair plume often released during laser hair removal is a biohazard and that smoke evacuators, good ventilation, and respiratory protection should therefore be employed for health-care workers involved in this procedure, especially those who undergo prolonged plume exposure. Using gas chromatography-mass spectrometry, the investigators found known or suspected carcinogens and known environmental toxins in the plume.[19]