Removal of unwanted facial hair
Unwanted facial hair is a common condition that often goes untreated. Women most often seek treatment, but men may also have concerns about this problem. (1) In most cases, a severe underlying medical condition is not the cause of unwanted facial hair. Its presence, however, causes significant psychologic stress and may lead patients to resort to uncomfortable and often expensive means of removal.
Hair Growth Cycle
The growth of human hair is cyclic, involving phases of active growth (anagen) and quiescence (telogen). In addition, an intermediate stage of transition, known as catagen, occurs between active growth and cessation of growth. Between 85 and 90 percent of hairs are in the anagen phase at any one time, with the remainder in telogen. (2-4)
During the anagen phase, mitotic activity in the hair bulb and dermal papilla resumes and forms the new hair shaft, pushing out the old inactive hair, or club hair, as the new hair advances. The matrix cells, which form the new hair, multiply rapidly and ascend into the follicular canal, dehydrate, and form the growing shaft. The visible hair shaft is composed of an outer cuticle, the cortex and, sometimes, a core of compact, keratinized cells, all of which are made of protein. (2-5)
Hairs that are in the anagen phase during removal are more sensitive to the various treatment modalities than hairs in the telogen phase. Alteration of matrix cell activity during anagen, by whatever method chosen, increases the amount of time from removal to regrowth. As a result, one of three alterations can occur: early cessation of anagen causing telogen to occur, transition into a dystrophic stage of anagen, or degeneration of the matrix. (5-8)
Depending on the site of the hair, the time spent in each phase differs considerably, from an anagen phase of two to six years for scalp hair to one to two months for thigh hair. The telogen phase also varies, ranging from one and one half months for mustache hairs to three to six months for leg hairs. (5) During telogen, growth stops, and the entire structure rests for a variable period of time, depending on the site. Once anagen begins, the remaining club hair is ejected, and the growth cycle continues.
Patterns of hair growth vary greatly depending on whether the patient is male or female. In addition, ethnicity may also determine normal growth patterns that can be interpreted as abnormal by physicians outside of a patient's native culture. Growth of androgen-sensitive hairs at various regions of the body (beard, axillae, pubis, chest, and shoulders, for example) can arouse suspicion of an underlying organic cause. (2,3) Overproduction of testosterone and other androgens in female patients may cause abnormal growth patterns that can be clinically evident as hirsutism. (2,3) All such patients should be evaluated for an underlying cause of the hair growth, whether the unwanted facial hair is to be treated or not.
Methods of Hair Removal
Several methods of hair removal are available, each with varying degrees of cost, efficacy, and side effects. Methods of hair removal are summarized in Table 1.
SHAVING
Shaving does not change the thickness or growth rate of human hair. (5,9) Rather, the rough-textured, beveled edge that shaving produces (compared with the softer, tapered tip of uncut hair) may give the appearance of thickening. (5,6) Although shaving is a useful and safe method of facial hair removal (and the chief method chosen by men), it is not popular among women.
Side effects of shaving are generally minimal. Irritation, often caused by components of the shaving lubricant, and minor cuts can occur. Pseudofolliculitis barbae, caused by the ingrowth of curly hair, is also a fairly common side effect in some ethnic groups. (5)
EPILATION/DEPILATION
Epilation, or plucking, is often the first method chosen by patients. The entire hair shaft and bulb are removed, with results lasting six to eight weeks. (5,10) While this method is probably the least expensive, it is not practical for use over larger areas. Unless the hair is plucked in anagen, the method generally does not change the growth rate of hair. (11,12) Plucking during anagen may shorten the duration of time spent in this phase and, if repetitive, may permanently damage the matrix. (5,6 )
Numerous methods are used for epilation, from tweezers to devices that pluck several hairs at once. Hot or cold waxing is also a form of epilation. Mixed with the wax is a resin that hardens around the hair shaft and aids in pulling out the hair when the wax has dried. Side effects, which are more common when more than one hair is removed at a time, include burns (from hot wax products), folliculitis, pseudofolliculitis, postinflammatory hyperpigmentation, and scarring. (5,13)
Depilation is the use of a chemical that dissolves the hair shaft, with results lasting up to two weeks. (5,14) Composed of thioglycolates and mercaptans, and mixed with an alkali compound (calcium hydroxide or sodium hydroxide), depilatories do not affect the hair bulb. (5,14) The thioglycolates disrupt disulfide bonds between the cystine molecules found in hair, helping to dissolve the hair shaft. (5,14) The addition of an alkali compound increases the pH level and can improve the efficacy of the depilatory.
