Removal of unwanted hair

INTRODUCTION — The majority of postpubertal persons in the world regularly practice some form of hair removal. Be it shaving, plucking, or other methods, most of us have hair on some part of our bodies that we wish to remove.

This topic reviews options for removal of unwanted hair. There are only limited data from clinical trials, so much of the information presented here is based on expert opinion. The evaluation and management of hirsutism are discussed separately. (See "Pathophysiology and causes of hirsutism" and "Evaluation of premenopausal women with hirsutism" and "Management of hirsutism in premenopausal women".)

HAIR GROWTH — We are born with all the hair follicles we will ever have [1]. At puberty, as a result of androgenic effects, some of these follicles enlarge and produce their characteristic growth patterns (beard growth, pubic hair). In some people, hair growth has a strong genetic influence leading to some of the more predictable ethnic patterns of hair distribution and thickness. The cells of the matrix at the base of the hair shaft differentiate under the influence of the dermal papilla and then proliferate to form the growing hair. Melanocytes within the matrix give the hair its color. The primary growth phase of the hair is called anagen, and it makes up the majority of the time a hair spends in the growth cycle. The other two phases are called catagen and telogen. (See "Evaluation and diagnosis of hair loss", section on 'Hair cycle'.)

During catagen, the hair follicle involutes, bringing an end to the active growth phase (anagen). The next phase, telogen, is the quiescent or resting phase that typically lasts for several months. At this stage, hair may be shed by brushing or during washing. Most hairs spend the majority of time in anagen (80 to 90 percent of the growth phase); however, this depends upon where the hairs are located. Scalp hairs typically spend the most time in anagen and can remain in anagen for several years before transitioning to telogen. Eyebrows and lashes have a much shorter anagen phase, and thus a relatively shorter length. It is during anagen that a hair is most susceptible to some of the newer methods of removal [2,3].

REMOVAL OPTIONS

Temporary methods — The following methods typically result in only temporary removal of hair; however, in some circumstances the dermal papilla may be damaged by the removal, leading to permanent removal of hair.

Plucking/epilation — A relatively safe and inexpensive method of hair removal is epilation, better known as plucking. The term "epilation" means to extract hair [4]. Plucked hairs can remain absent for six to eight weeks [2,3,5]. However, plucking can be very uncomfortable and time consuming. Further, epilation can cause irritation (folliculitis) due to the traumatic nature of the procedure. In some patients, particularly those with highly pigmented skin, the trauma induced by plucking can lead to postinflammatory hyperpigmentation. Scarring can also occur in predisposed individuals.

Plucking hairs during anagen probably maximizes the effect and increases the likelihood of destroying the dermal papilla, which could lead to permanent hair removal in some patients [2]. In general, though, hair typically regrows after being plucked. In a study comparing axillary hair plucking with electrolysis, plucking did not reduce hair counts [6].

Plucking can be performed with tweezers, by use of thin threads (threading), or any one of a number of commercially available devices and is best suited for relatively small areas such as the face.

Waxing — Waxing, which is technically a form of epilation, involves applying a layer of wax to the area where hair removal is desired. When the wax is pulled off, the trapped hairs are pulled out. Although operator dependent, waxing may be less painful than plucking individual hairs.

Waxing can be performed with either a molten wax or a room temperature liquid wax (called cold wax). The hot wax treatment causes follicular dilatation allowing entire hairs to be removed down to the bulb. The "cold wax" treatment sometimes uses an added resin to entrap hairs and allow them to be pulled out, also at the bulb.

Waxing can be used on a broad range of body areas such as eyebrows, back, bikini area, and legs. As long as the hairs are removed with the bulb intact, one can expect similar results to plucking [2,5].

Depilation — Depilation is the use of a chemical (a depilatory agent) to essentially dissolve the hair. The active ingredients in most products are thioglycolates, which chemically disrupt disulfide bonds in the hair [2]. The end result is dissolution of the hair into a gelatinous form, which can be wiped or scraped away.

Depilatories work well, but the results do not typically last much longer than two weeks [2]. In addition, since most depilatories are sulfur-containing compounds, the odor produced can be unpleasant.

Depilatories are used most often on bikini areas and legs but can be used on various areas of the body. Depilatories may be particularly useful in men with severe ingrowing of facial hair (pseudofolliculitis barbae); however, when used for this purpose they may cause severe irritation leading to postinflammatory hyperpigmentation in some individuals. (See "Pseudofolliculitis barbae", section on 'Chemical depilatories'.)

Irritant or allergic contact dermatitis can occur with the use of depilatories as a result of the sulfur component in addition to added coloring and fragrances. Different strengths and compounds can be tried if irritation occurs.

Shaving — Shaving is a popular method of hair removal. Methods of variable expense are available including old-fashioned straight razors, multiple blade safety razors, and electric shavers.

Shaving only removes hair down to just below the surface of the skin. When used for facial hair, most people must repeat the process daily with some needing retreatment in less than 12 hours. The process is purely mechanical and provides only shortening of the hair involved. Most body areas are amenable to shaving.

Shaving does not cause hair to grow back thicker [2,7,8]. Rather, the sharp, beveled edge created from the shearing off of the hair creates the rough texture. Thickening of hair is produced by exposure to androgens either as a normal result of sexual maturity or in pathologic disease states.

Shaving can produce skin irritation either from the cutting process of the blade, or from the shaving creams, gels, and other facial preparations intended to smooth the process. Pseudofolliculitis barbae (razor bumps, shave bumps) is a common complication, particularly in Black men. Shaving also may nick or abrade the epidermis, increasing the risk for superficial infection (eg, folliculitis) by bacteria, such as Staphylococcus aureus, or fungi, such as Pityrosporum. (See "Pseudofolliculitis barbae" and "Infectious folliculitis".)

In addition, shaving can lead to the spread of viral warts (verruca vulgaris and condyloma) or molluscum contagiosum. It is advisable to avoid shaving the involved areas entirely, especially during treatment of warts or molluscum. Patients who have these lesions and still choose to shave should be advised to not use the same razor on other areas of the body.

Bleaching — Although not a method of hair removal, bleaching is a relatively common method for masking the presence of undesired hair, particularly facial hair [9]. A variety of products are available, all of which contain hydrogen peroxide and sulfates. These components lighten and soften the hair, making it less conspicuous.

Patients can develop a reaction to the active ingredients, as with all chemical methods of hair control. Side effects include irritation, pruritus, and possible skin discoloration. In addition, patients with sensitivity to sulfa may want to avoid these products. Testing the product on a small area of skin prior to use may help the patient avoid a more pronounced reaction.

Pharmacologic options — Pharmacologic therapy is commonly used for the treatment of hirsutism (excessive male-pattern hair growth) in women. The main systemic treatment options are oral contraceptives and antiandrogens. A systematic review of randomized trials found evidence to support the efficacy of oral contraceptives as well as the antiandrogens spironolactone and flutamide [10]; however, trials are limited and the quality of evidence is low overall. Additional studies will be useful for clarifying the relative efficacy of systemic therapies. Pharmacologic treatment of hirsutism is discussed in detail separately. (See "Management of hirsutism in premenopausal women".)

Eflornithine is a topical option for the treatment of hirsutism in women. Eflornithine 13.9% cream can reduce hair growth by irreversible inhibition of ornithine decarboxylase, an enzyme important for normal hair growth; it is approved by the US Food and Drug Administration (FDA) for removal of facial hair in women. Unpublished data from the manufacturer on two randomized trials involving 594 women treated for 24 weeks found that more women had at least marked improvement with eflornithine than with placebo (32 versus 8 percent) [11]. Noticeable results take about six to eight weeks, and once the cream is discontinued hair returns to pretreatment levels after about eight weeks. The drug is not covered by most insurance companies in the United States.

Clinical trials have also found that combining eflornithine with laser hair removal results in a more rapid response than laser treatment alone [12,13].  

Eflornithine can cause an acneiform eruption in 20 to 30 percent of patients [13]. Systemic absorption is low when it is applied topically [14].

Laser and intense pulsed light — Photoepilation therapies (laser and intense pulsed noncoherent light sources [15]) can be used to reduce hair via selective photothermolysis. Total removal of hair is uncommon, and realistic expectations for treatment include less hair, lighter hair, and thinner hair. In general, dark hair responds best. (See "Principles of laser and intense pulsed light for cutaneous lesions".)

Coupling the absorption characteristics of a target (melanin in the case of hair, also known as the "chromophore") with a laser of a corresponding wavelength allows for the selective targeting of the specific chromophore within the matrix. Ideally, the wavelength of laser light should be selectively absorbed by melanin only within the hair bulb, thus destroying only the hair and theoretically resulting in permanent removal. However, competing structures within adjacent skin can cause laser energy to be absorbed by pigment in the epidermis in addition to melanin within the hair bulb, thus reducing the effectiveness of the treatment and increasing the potential for adverse effects.

An early study of 183 patients of varying skin phototypes who were treated over the course of a year with up to six treatments with a 694 nm ruby laser found that six months after a single treatment, 67 percent of patients had a greater than 50 percent reduction in hair at the treatment site [16]. Multiple treatments increased the percentage of patients with 50 percent reduction to 90 percent. However, by one year there was a return of fine vellus hair in the majority of patients. All body sites were represented in this study. More modern lasers now allow better selective photothermolysis with less potential for complications.

Several different wavelengths of laser or intense pulsed light (IPL) are available for photoepilation (table 1) [17-19]. The ideal subjects for laser hair removal are people with lightly pigmented skin and dark hair in whom most of the laser energy is absorbed by melanin in the hair bulb rather than by the surrounding epidermis. The efficacy of most lasers and IPL is greatest for darker pigmented hair (black > brown > gray, red, or blonde > white), while the risk of burns and skin tone interference increases with increasing skin pigmentation. However, continued advances in laser technology have given people with more darkly pigmented skin better options for laser hair removal [20,21]. As an example, a study in 144 subjects with Fitzpatrick skin types III to V found that treatment with a long-pulsed alexandrite laser (755 nm) could effectively remove hair without scarring or long-term pigment changes; hair reduction at nine months was greater after three treatments than with two or one (hair reduction of 55, 44, and 32 percent, respectively) [22].

One popular laser used for hair removal in individuals with darkly pigmented skin is the 1064 nm long-pulsed neodymium-doped yttrium aluminum garnet (Nd-YAG) laser. It has demonstrated efficacy in all skin types and is particularly effective in those with darkly pigmented skin [21]. It is particularly helpful in patients with pseudofolliculitis barbae. Since this laser operates in the infrared region of the spectrum the side effects are those related to heat. Patients may often be pretreated with a topical anesthetic cream to reduce discomfort. Four percent lidocaine in a cream vehicle is one of the most commonly used medications. In addition, posttreatment cooling can reduce some of the related discomfort from this laser.

Success rates of laser therapy are not completely explained by hair growth phase and melanin content [23]; overall success is likely determined by a combination of hair location, skin and hair color, the stage of hair growth, laser type, and treatment plan [24].

Since the hair matrix is most sensitive to laser treatment while it is in the anagen phase, multiple treatments are necessary. This is to ensure all hairs have been treated during this most sensitive phase of growth. Patients typically require four to six treatments spaced approximately four to six weeks apart in order to achieve satisfactory hair removal [22]. Adjustments of laser settings are often needed for optimal results. Once the primary course is complete, patients may require maintenance treatments once every 6 to 12 months to remove the smaller vellus hairs that may grow back.

IPL systems have been shown to be as effective as laser in hair removal. An intense pulsed light system makes use of a flash-lamp that produces intense light of a range of wavelengths depending on the intended target. IPL devices produce light in the 500 to 1200 nm range. Various filters allow the narrowing of the emitted wavelength band. IPL systems also can be used for the treatment of pigmented and vascular lesions.

Laser or IPL therapy is probably best suited for people who desire treatment of large areas or areas with dense hair growth, but like electrolysis, can also be used for smaller areas [18]. Laser or intense pulsed light can cause irritation and postinflammatory pigment changes. In addition, pain, erythema, blistering, and scarring are possible [18,19,21,24,25]. Paradoxical hypertrichosis of the treated areas appears to be a rare complication of laser therapy [26,27].

Photoepilation therapies are the most expensive methods of hair removal/reduction. A systematic review found two trials that suggested that laser therapy was more effective than electrolysis; however, these trials were very small and had other methodologic problems [17].

Home-use laser and light-based devices — A number of home-use devices have been developed for the treatment of unwanted hair. Depending on the device, the clinical response is achieved either by a laser, intense pulsed light flash lamp (IPL-FL) or a combination of IPL-FL and radio frequency radiation (RF). The home-use lasers generally derive their light from a diode that emits an 808 nm beam [28].

Peer-reviewed studies of home-use devices are limited, and the available data primarily consist of industry-sponsored, uncontrolled studies with relatively short follow-up periods [29]. In the United States, such products are categorized by the US Food and Drug Administration as cosmetic products, meaning that they are subject to much less rigorous evaluation of safety and efficacy prior to commercial distribution than products classified as medical devices.  

The relative low cost (most products are priced less than $1,000) of home-use laser and light-based devices make them attractive alternatives for many patients. Some devices may yield modest results [29]. However, additional study is necessary for conclusions on long-term efficacy and relative efficacy compared with the more powerful devices used for professional laser and light treatments.

Electrolysis — Electrolysis, if performed properly, is technically the only permanent method of hair removal. However, since technique can vary among electrologists, many patients can experience hair regrowth. This method is rarely performed by physicians, but may be offered in a "spa-like" setting as one of several methods for hair removal.

Electrolysis is performed by inserting a very fine needle into the hair follicle and applying an electrical current. The basis of its therapeutic effect is the destruction of the rapidly dividing cells of the matrix and the follicle itself.

First reported in 1875, electrolysis began with the use of direct current, also called galvanic electrolysis [30]. In the galvanic method, the destruction occurs as a result of the electrical effect on saline in tissues. Sodium hydroxide is produced at the tip of the needle causing the chemical destruction of the hair bulb and dermal papilla. Galvanic electrolysis is a slow process.

The development of thermolytic electrolysis using high frequency alternating current (commonly 13.56 MHz or 27.125 MHz) improved results and reduced the tissue injury caused by galvanic electrolysis [2,31]. Thermolytic electrolysis creates heat at the needle tip destroying the follicle. It is much more rapid, and as a result, electrolysis now typically involves either thermolytic electrolysis or a combination of galvanic and thermolytic electrolysis referred to as "the blend" [32].

Electrolysis can be effective in reducing hair counts [6]. There are no controlled clinical trials comparing each method although the theory behind electrolysis implies permanence [33]. In the best hands, many patients have permanent hair removal with 15 to 25 percent regrowth at the end of six months [2,31]. Given the overall slower nature of the procedure, it is better suited for relatively small areas, though one could, with regular sessions over a long period, remove hair from larger areas.

Electrolysis can be painful. Topical anesthetic creams, such as eutectic mixture of local anesthetics (EMLA; lidocaine-prilocaine) or lidocaine cream (LMX), may be helpful in reducing pain when electrolysis is performed in sensitive areas [34,35]. Electrolysis can cause erythema and postinflammatory pigment changes; it involves tissue destruction, and scarring is possible. It is felt that patients with pacemakers should not undergo electrolysis, as the electrical field generated by thermolysis and direct current through the body could interfere with pacing and possibly cause the device to fail [2,5,31].

Electrolysis, like any injury, may promote a flare of topical herpes simplex virus (HSV) (see "Epidemiology, clinical manifestations, and diagnosis of herpes simplex virus type 1 infection"). Patients with recurrent HSV may want to consider antiviral prophylaxis when treated with electrolysis [2]. (See "Treatment and prevention of herpes simplex virus type 1 in immunocompetent adolescents and adults", section on 'Prophylaxis for recurrent HSV with identified trigger'.)

Perhaps the biggest drawback of electrolysis is the lack of standard regulations governing its practice [30]. The laws regulating electrolysis vary from state to state. Many states require no training before one sets up practice. In the best hands, the method can produce permanent results [2,30,31]. However, there is a great deal of variability in skill as a result of nonstandard regulations and the different types of equipment used.

SUMMARY AND RECOMMENDATIONS — Options for removal of unwanted hair include methods that temporarily remove hair (plucking, waxing, shaving, chemical depilatories, and pharmacologic methods) and methods that may be able to permanently remove hair (electrolysis and laser/light treatments). Decisions among these options involve patient preferences, tolerance of discomfort and pain, risks of complications, and cost. In general:

●Plucking hairs can temporarily remove hair for six to eight weeks, may be uncomfortable, and is best suited to small numbers of hairs, such as on selected areas of the face. (See 'Plucking/epilation' above.)

●Waxing accomplishes the same effect as plucking. If it is well tolerated, like plucking it can be used on small numbers of hairs (eg, face) and can also be used for small or delicate areas (eg, bikini area). Unlike plucking, it may also be appropriate for larger numbers of hairs and/or hair removal over a wider area (eg, back, legs). (See 'Waxing' above.)

●Chemical depilatories can painlessly remove hair, but they may cause irritation and may have an unpleasant odor. They can be used on virtually any body area as long as there are no significant problems with side effects such as irritation. (See 'Depilation' above.)

●Shaving is generally safe, but it can produce skin irritation and must be repeated frequently. Repeated shaving does not cause hair to thicken. Shaving can be used on any body area. (See 'Shaving' above.)

●Laser therapy and intense pulsed light may also remove hair, but do not always result in complete permanent removal. Some patients may require periodic maintenance treatments. Laser/light hair removal is highly effective for small areas (eg, face, bikini area) or large areas such as the arms, legs, chest, and back. Pigmentary changes are uncommon side effects and scarring is rare. (See 'Laser and intense pulsed light' above.)

●Electrolysis can permanently remove hair when done correctly, but it is a slow process that can be uncomfortable and can occasionally cause scarring. Electrolysis is typically used on selected areas of the face (eg, eyebrows, chin, upper lip), but it can also be used in the bikini area and other small areas. (See 'Electrolysis' above.)

●Eflornithine cream can reduce amounts of unwanted facial hair in women, but it takes six to eight weeks to be effective, and the hair returns within about eight weeks after the cream is stopped. Although approved by the US Food and Drug Administration (FDA) only for the face, it could theoretically be used in other areas. However, it's expensive and generally not covered by most insurance plans in the United States, which may limit its practicality to smaller areas. (See 'Pharmacologic options' above.)