You are in: eMedicine Specialties > Plastic Surgery > ANCILLARY PROCEDURES Laser Hair RemovalArticle Last Updated: Feb 21, 2007AUTHOR AND EDITOR INFORMATIONSection 1 of 10
  Author: Joseph A Molnar, MD, PhD, FACS, Associate Professor, Department of Plastic and Reconstructive Surgery, Wake Forest University School of Medicine; Associate Director, of North Carolina Hospital Burn Unit, Wake Forest University School of Medicine Joseph A Molnar is a member of the following medical societies: American Association of Plastic Surgeons, American Burn Association, American College of Surgeons, American Medical Association, American Society for Parenteral and Enteral Nutrition, American Society of Plastic Surgeons, North Carolina Medical Society, and Wound Healing Society Coauthor(s): Christian N Kirman, MD, Staff Physician, Department of Plastic and Reconstructive Surgery, Wake Forest University Baptist Medical Center; Samer Alaiti, MD, Clinical Assistant Professor, Departments of Dermatology and Internal Medicine, University of California at Los Angeles School of Medicine Editors: James F Thornton, MD, Assistant Professor, Department of Plastic and Reconstructive Surgery, University of Texas Southwestern; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Mark E Krugman, MD, Assistant Professor of Plastic Surgery and Clinical Professor of Otolaryngology-Head and Neck Surgery, University of California at Irvine School of Medicine; Nicolas (Nick) G Slenkovich, MD, Practice Director, Colorado Plastic Surgery Center at Swedish Medical Center; Jorge I de la Torre, MD, FACS, Professor of Surgery and Physical Medicine and Rehabilitation, Residency Program Director, Division of Plastic Surgery, University of Alabama at Birmingham; Director, Center for Advanced Surgical Aesthetics Author and Editor Disclosure Synonyms and related keywords: laser-assisted hair removal, laser hair removal, unwanted body hair INTRODUCTIONSection 2 of 10
  Up to 22% of women in North America have excessive or unwanted facial hair, which negatively affects the quality of life for many individuals. Men also feel compelled to rid themselves of unwanted body hair, as dictated by popular culture and appearance anxieties. Body hair may be undesirable for patients for cultural, social, cosmetic, or psychological reasons; unwanted hair can result in feelings of embarrassment or emotional burden that may impede patients' relationships or daily activities. This level of impairment is comparable to that experienced by patients with psoriasis and eczema and eclipses that experienced by patients with acne. Adequate methods for hair removal have long been in demand; long-term hair removal with minimal adverse effects is the ultimate goal. Laser hair removal has become well established as an effective form of treatment for unwanted body hair. The shaving and hair removal market in the United States increased 14.5% between 1998 and 2003 and currently exceeds 2.1 billion dollars annually. None of the hair removal methods practiced today provides complete or permanent hair removal. This goal will likely be reached with a more complete understanding of anatomy, physiology, hair growth cycles, and laser-tissue interactions, and as more sophisticated technologies emerge. History of the ProcedureNumerous methods are successful in temporarily removing hair.
EtiologyExcessive hair growth in men or women may be classified into either hirsutism or hypertrichosis, depending upon the distribution on the body. Other disorders, such as pseudofolliculitis barbae or acne keloidalis nuchae, may be caused by the hair itself, causing ingrown hairs and localized inflammatory reactions that may result in pigmentary disorders, hair loss, and scarring. INDICATIONSSection 3 of 10
Hirsutism Hirsutism is defined as an excess of thicker darker hairs in a male pattern of distribution where they are normally thin or absent in the female. Affected areas are those that are stimulated by circulating androgens and include the face, chest, arms, and areolae. This disorder may be caused by several types of endocrine disorders that lead to excessively high androgen levels or by hair follicles that are particularly sensitive to normal levels of androgens. The latter accounts for approximately 95% of all reported cases. An estimated 1 in 20 women of reproductive age are affected by this disorder. Treatment for excessive hair in hirsutism is not generally required if no clear etiology of the disorder exists and the patient does not find the excessive hair growth objectionable. However, treatment generally relies upon antiandrogen to inhibit the effects of androgens on the skin, such as 5-alpha-reductase inhibitors, spironolactone, or flutamide. Whether choosing to treat medically or with any of the aforementioned methods of hair removal, patients must understand that treatment is long-term and must be continued to maintain low levels of visible hair. Hypertrichosis A hair growth pattern in a nonandrogen-dependent pattern is termed hypertrichosis and may involve vellus, terminal, or lanugo type hair. This may be associated with a number of congenital syndromes or occur as an isolated finding. What is considered a normal amount and appearance of body hair can vary widely among different ethnic groups, and treatment should be tailored to the needs or desires of the individual patient. Hypertrichosis may be an unwanted adverse effect of medications such as cyclosporine, minoxidil, and oral and topical corticosteroids that are used to treat other disorders. Pseudofolliculitis barbae When hair grows in a curly and tightly coiled pattern, patients may be afflicted with numerous ingrown hairs that may cause skin irritation, papules, and pustules. These may eventually lead to changes in pigmentation and even scarring. Pseudofolliculitis barbae occurs most commonly in the underarm or bikini area with shaving, or, in men, at the lower neck, where coarse facial hair grows. Laser hair removal is effective in treating this disorder by temporarily or permanently removing the hair from the chronically inflamed lesion. Laser treatment leads to resolution and healing of the papular and pustular lesions, dramatically improving skin texture and the associated postinflammatory hyperpigmentation. Acne keloidalis nuchae This condition is most commonly seen in African Americans and is characterized by follicular papules and chronic plaques on the occipital area of the scalp. It may often lead to keloidal thickening of the skin and permanent scarring. In early lesions, an entrapped hair is usually in evidence, and early treatment with laser hair removal is most effective at this stage. The entrapped hair acts as a foreign body in the skin and, when chronic, can cause skin changes, decreased hair growth, and scarring of the affected area. The treatment goals with laser hair removal for this disorder are to destroy the impacted hair and cause a delay in new hair growth, thus decreasing further scarring. RELEVANT ANATOMYSection 4 of 10
In order to gain a more comprehensive understanding of how laser hair removal procedures work, one must have knowledge of relevant hair microanatomy, physiology, and growth cycles associated with growth of hair on the body. Hair follicles are found over almost the entire body surface, with the exceptions of the palms of the hands and soles of the feet. Each person has approximately 5 million individual hair follicles. Hair follicles may be straight, wavy, helical, or spiral, and the morphologic features of follicles vary among different anatomic locations and racial backgrounds. White persons typically have thinner hair shafts than persons of Asian or African American backgrounds. The density of hair follicles in a given skin surface area also varies widely among individuals. Hair shape is also highly variable; on cross-section, straight hair tends to be round and wavy or spiral hair is oval. Keep in mind the variations in color, texture, and amount of hair on a given body surface area when deciding upon the need for hair removal procedures. Types of Hair Adult hair has 2 primary types. Vellus hair can be found over the entire body and appears as soft, fine, short hairs that are nonpigmented or very lightly pigmented and can be all but invisible. Terminal hair is the longer, coarser, and more darkly pigmented hair found on the scalp, underarm area, and groin. Subgroups of terminal hair include those on the scalp, pubic region, and eyebrows. Terminal hair is also found on the androgen-sensitive areas of the body, such as the beard and chest area in males. Although greatly outnumbered by vellus hairs, terminal hairs are more important, as they are responsible for the appearance of hair on the body. They may aid in enhancing a person's image, or they can cause great anguish and distress due to their distribution, length, or texture. Hair follicle anatomy Hair follicles are associated with other structures within the skin. As the hair follicles develop, they become associated with developing sebaceous glands, apocrine glands, and erector pili muscles. Together, these structures form the folliculosebaceous-apocrine unit. Each hair follicle may be divided into 4 histologic divisions, which are (from superficial to deep) the infundibulum, isthmus, stem, and bulb.
Hair phases Adult hair has 3 distinct phases of development: anagen, catagen, and telogen. As hairs progress through these phases, they are affected differently by treatment with laser-assisted hair removal.
The length of time spent in each phase depends upon the location of the hair. On the scalp, hair follicles spend up to 10 years in anagen, but on the trunk, brow, and limbs, anagen lasts no longer than 6 months. Catagen lasts only 2-3 weeks, and telogen lasts from 3-4 months. Up to 90% of hairs in a given body location can be in the anagen phase at a given time. This fact becomes important because only hairs in the anagen phase of development are susceptible to injury during a session of laser-assisted hair removal. Thus, multiple treatments are necessary to treat all hair follicles on a given body surface area. Melanin Melanin is a biologic pigment that is found in many cells in the body and is primarily responsible for the color of the skin and hair. The primary function of melanin in the skin is to protect it from the harmful effects of sunlight. The amount of melanin in hair and skin varies widely between individuals and races and is determined by the concentration of melanin within the skin. This variability produces a great range of hair darkness, skin color, and tone. Melanin is the target chromophore, or light-absorbing molecule, for laser treatment and has an absorption spectrum of 250–1200 nm, which spans the entire ultraviolet, visible, and infrared light ranges. Melanin absorbs energy in the form of heat from a pulse of laser light. This heat causes thermal injury to the melanin-containing cell and its surroundings. Ideally, the laser energy is absorbed selectively by the melanocytic hair bulb and matrix, thus destroying the hair follicle and its capacity to regrow, while protecting the surrounding tissue where the melanin concentration is minimal. In persons with darker skin, however, the higher levels of melanin in heavily pigmented skin compete as a chromophore for the laser light. This light is converted to heat and can cause skin blistering or changes in skin pigmentation. CONTRAINDICATIONSSection 5 of 10
TREATMENTSection 6 of 10
Surgical TherapyLaser-assisted hair removal is accomplished by destroying the follicular unit and thus inhibiting future hair growth by the follicle. The ability to accomplish this without damaging any surrounding tissue is based on the theory of selective photothermolysis. The theory states that at a particular wavelength (in nm), pulse duration, and fluence matrix, lasers or other light sources with wavelengths within the absorption spectrum of melanin are effective for hair removal. Typically the pulse duration, or length of time the pulse of light is emitted, should be shorter than or equal to the thermal relaxation time (TRT) of the target. The TRT of a hair follicle is from 10-100 milliseconds. However, pulses longer than the TRT of the hair shaft allows thermal damage to occur in the hair matrix stem cells and ensure follicular destruction. In order to minimize the risk of thermal damage to surrounding skin cells, cooling devices may be used to chill the skin before or during laser treatment. Laser systemsSince the first lasers were approved for the use of hair removal in 1996, dramatic advances have occurred in laser technology. This has led to the development of several laser types for the treatment of unwanted hair. Before the widespread use of longer wavelengths and pulse durations and more effective cooling devices, laser-assisted hair removal was best used to treat individuals with light skin and dark hair. More recently, however, long-pulsed lasers have been used to safely and effectively treat patients with darker skin types. Laser light sources currently used to destroy hair photothermally include the long-pulsed ruby (694 nm), long-pulsed alexandrite (755 nm), long-pulsed diode (810 nm), and long-pulsed neodymium:yttrium-aluminum-garnet (Nd:YAG, 1064 nm). The efficacy of these different lasers for treatment of unwanted hair and the frequency of adverse effects encountered after treatment have been compared in various skin types. The efficacy of each of the following laser systems is compared in terms of permanent hair reduction. Hair reduction, as defined by the FDA, "refers to a significant reduction in the number of terminal hairs after a given treatment, which is stable for a period of time longer than the complete growth cycle of hair follicles at the given body site." Long-pulsed ruby The long-pulsed ruby laser was the first widely used laser for hair removal. Its light energy has the most selective absorption by melanin and the shortest depth of penetration (wavelength of 694 nm). Use of this laser for hair removal is indicated in individuals with light skin and dark hair. Its efficacy in individuals with light skin has been demonstrated in numerous studies, ranging from 20-60% hair reduction after one treatment and up to 50-78% reduction after multiple treatments. The ruby laser penetrates the skin by only 1-2 millimeters and can cause significant absorption by epidermal melanin of thermal energy. In studies treating a wide range of skin types with the ruby laser, more adverse reactions have occurred in patients with darker skin. The use of this laser on patients with darker skin types is not recommended. Long-pulsed alexandrite The 755-nm alexandrite laser has now been widely used for laser hair removal and is recognized as being efficacious and generally safe. This laser is still typically used for patients with lighter skin types, but its longer wavelength allows for deeper penetration into the skin, and it can be used for patients with darker skin. Studies have reported hair reduction from 4-56% after only a single treatment and from 33-95% hair reduction after multiple treatments, depending upon number of treatments and body location. The adverse effects of this laser, when used on patients with darker skin types, can include blistering, crusting, and alterations of pigment, even when skin cooling devices are used. In patients classified as having the darkest skin, residual hypo- or hyperpigmentation is the rule with the alexandrite laser. Long-pulsed diode Treatment of unwanted hair with the 810-nm long-pulsed diode laser has been demonstrated as comparable to those of the ruby or alexandrite lasers. After a single treatment, hair reductions of 32-34% have been reported, and up to 84% hair reduction has been reported after multiple treatments. The diode laser has a longer wavelength and adjustable pulse duration, and, when used with an efficient skin-cooling device, allows for the treatment of patients with darker skin types. The diode laser is more effective for laser-assisted hair removal in patients with dark skin because of the higher absorption by melanin than is seen with the Nd:YAG laser. Still, temporary adverse effects have been reported with the use of the diode laser in the form of postinflammatory hyperpigmentation when used on individuals with dark skin. Long-pulsed Nd:YAG The Nd:YAG laser is the safest type used to treat unwanted hair on patients with dark skin and is most suitable for patients in this group. At 1064 nm, this laser penetrates the skin deeper than other lasers (to a level of 4-6 mm) with less absorption at the skin, but it is also less effectively absorbed by melanin. This leads to lower instances of adverse effects and better tolerance in patients with dark skin, but also lower efficacy for hair removal. Permanent hair loss has been reported, however, with reported hair reductions of 27-53%, depending on the number of treatments administered and the body location. The FDA has approved the long-pulsed diode and the long-pulsed Nd:YAG lasers for use in hair removal in patients with darker skin classifications. All FDA-approved laser systems used for hair removal must have efficient and effective epidermal cooling devices incorporated as part of the system. Intense pulsed light systems Pulsed, noncoherent broadband light sources are now accepted and widely used in the medical industry for hair removal and other applications. Intense pulsed light (IPL) systems utilize a xenon bulb as a light source, which produces polychromatic light with wavelengths from 550-1200 nm. This is in contrast to laser light sources, which produce monochromatic light of a specific wavelength. Light emitted by the bulb passes through a filter that excludes shorter wavelengths that may severely damage skin. The ability to "tune" the wavelength of light emitted by these systems gives IPL systems the advantage of versatility. Using different filters, a pulsed light system could mimic any number of laser systems, allowing the operator to treat many different conditions amenable to light therapy, including, of course, the removal of unwanted hair. Studies have shown intense pulsed light to be an effective method of hair removal. In a study of 210 patients who underwent hair removal by IPL, a mean hair reduction of 80% was reported after 3-5 treatments. Minimal adverse effects, including transient erythema and localized edema, were reported. The variability of light output can also be a disadvantage of IPL systems. The light spectrum may vary slightly with each pulse, and reproducibility of treatments varies between operators. The handpieces of IPL systems are typically larger than laser-based systems, which makes treatment of fine areas of the skin difficult. Preoperative DetailsA large discrepancy can exist between patient expectations of treatment with laser-assisted hair removal systems and the actual effects of such a treatment. Open communication must exist between the care provider and the patient. A body surface area does not realistically remain completely hair-free after a single laser-assisted hair removal treatment. Expectations
Skin preparation and safety
Intraoperative DetailsOptimal outcomes of laser-assisted hair removal are obtained with the highest fluences, appropriate pulse duration, and the largest laser spot size. Test spots may be performed prior to treatment of larger areas to determine to highest fluence tolerated by the individual patient and the laser's effect on surrounding skin. The amount of fluence used should also depend upon the area of the body to be treated and the density of hairs at the site.
To minimize the possibility of thermal damage to skin and to improve patient comfort, the skin should be cooled during laser-assisted hair removal. As previously stated, all FDA-approved laser systems have an epidermal cooling device incorporated into the handpiece. Incorporated cooling mechanisms currently in use include cryogen sprays, sapphire-cooled hand pieces, and cold airflow.
During laser treatment, each laser spot should overlap by no more than one third of the spot size. Further overlapping of continuous pulses causes accumulation of thermal injury and potentially causes epidermal damage. No overlapping of spots could result in missed areas in the treatment area. A treatment grid could be applied to the patient's skin and used as a guideline to outline the treatment area. With experience, the laser operator becomes proficient in visually tracking the treatment area. Postoperative Details
Follow-upFuture treatments should be planned when they are likely to be most effective. Timing depends upon the body surface area to be treated. Hair on the trunk and extremities grows more slowly than on the face and head, and future treatments to the trunk and extremity should be planned after 2-4 months. In women, facial hair is lighter in color and finer in texture than on other parts of the body. These hair properties make the face a resistant area to treatment. Therefore, greater numbers of treatments are often required, and at shorter intervals. Treatments of the face should be timed at intervals of approximately 4-6 weeks. COMPLICATIONSSection 7 of 10
Immediate effects after a single treatment of laser-assisted hair removal include perifollicular erythema and edema. These are expected after treatment and should not be considered adverse effects. They are minimized by cold application and resolve in a few hours. The risk of developing adverse effects or complications after laser-assisted hair removal varies widely and depends upon many factors. The type of laser used may contribute to the incidence of adverse effects.
The incidence of adverse effects was reported after laser-assisted hair removal was performed on 480 patients. Reported adverse effects included (from highest to lowest incidence) blistering, hyperpigmentation, scabbing, hypopigmentation, scar formation, and thrombophlebitis.
OUTCOME AND PROGNOSISSection 8 of 10
In a comprehensive evidence-based review of hair removal using laser light sources, outcomes from different laser treatments were evaluated. The levels of efficacy and adverse effects from treatment with ruby, alexandrite, diode, and Nd:YAG laser light sources were compared from the results of 8 randomized controlled and 20 controlled trials.
Active communication must exist between the clinician and the patient regarding indications, expectations, and treatment goals before laser-assisted hair removal treatment begins. The FDA definition of permanent hair reduction should be reviewed with the patient seeking treatment, as evidence-based clinical trials report their results based upon this definition. Advertisements throughout the media often portray laser-assisted hair removal that could lead to unrealistic goals of treatment, and this approach may lead to more realistic expectations from both the clinician and the patient. MULTIMEDIASection 9 of 10
REFERENCESSection 10 of 10
Article Last Updated: Feb 21, 2007 | |||||||||||||||||||
