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.
Hair-removing lasers and light sources
Since then, the market has flood 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 allow to cool efficiently while the melanin in the hair follicle heat. [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 likely cause 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.
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 treat, 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.
Medical Therapy
Alternative portfolio 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 currently approve for use on only the face and chin in female
adolescents and women older than 12 years. In theory, the agent can use as an adjuvant to laser hair removal.
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 later remove, and the area mark
(an eye-makeup marker works best) and photographed. If a cooling gel use, it apply at this stage.
If the handpiece offers dynamic cooling, it firmly apply to the skin.
Cautions about topical anesthetics
At least 3 deaths have link 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.
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 properly apply.
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 employee 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]
