Medical Care
Only two drugs currently have US Food and Drug Administration (FDA)–approved indications for treatment of androgenetic alopecia: minoxidil and finasteride.
Minoxidil
Although the method of action is essentially unknown, minoxidil appears to lengthen the duration of the anagen phase, and it may increase the blood supply to the follicle. [30] Regrowth is more pronounced at the vertex than in the frontal areas and is not noted for at least 4 months. Continuing topical treatment with the drug is necessary indefinitely because discontinuation of treatment produces a rapid reversion to the pretreatment balding pattern.
Patients who respond best to this drug are those who have a recent onset of androgenetic alopecia and small areas of hair loss. The drug is marketed as a 2% or a 5% solution, with the 5% solution being somewhat more effective. A 48-week study compared the 2 strengths in men. [31] Findings indicated that 45% more regrowth occurred with the 5% compared with the 2% solution. In general, women respond better to topical minoxidil than men. The increase in effectiveness of the 5% solution was not evident for women in the FDA-controlled studies. Subsequent studies have shown at best a modest advantage to the higher concentration in women. In addition, the occurrence of facial hair growth appears to be increased with the use of the higher-concentration formulation.
Central chorioretinopathy has been associated with the use of minoxidil 2% for androgenetic alopecia. A 37-year-old man developed this adverse effect consisting of a positive elative scotoma, metamorphopsia, and impaired dark adaptation of the right eye after 8 months use of minoxidil for androgenetic alopecia. However, 1 month after cessation of the drug, normal findings were found upon reexamination. [32]
Although not FDA-approved for the purpose, oral minoxidil has also come into use for the treatment of androgenetic alopecia. Hypertrichosis is oral minoxidil’s most commonly known adverse effect, although it occurs more often on higher doses of 5 mg per day than in patients taking 2.5 mg daily. There is also concern regarding the possibility with oral minoxidil of hypotension, tachycardia, pericardial effusion, lower limb edema, and electrocardiograph changes, although side effects tend to be dose-dependent and, when the drug is stopped, reversible. [33, 34]
In a survey of dermatology practitioners, Sanfilippo and Friedman found that most respondents supported the management of androgenetic alopecia with oral minoxidil. Support varied according to the number of years the providers had been in practice, with the least supportive being those who had been practicing for more than 30 years. [35]
Finasteride
Finasteride is given orally and is a 5-alpha reductase type 2 inhibitor. [36] It is not an antiandrogen. The drug can be used only in men because it can produce ambiguous genitalia in a developing male fetus. Finasteride has been shown to diminish the progression of androgenetic alopecia in males who are treated, and, in many patients, it has stimulated new regrowth.
Although it affects vertex balding more than frontal hair loss, the medication has been shown to increase regrowth in the frontal area as well. Finasteride must be continued indefinitely because discontinuation results in gradual progression of the disorder. A study in postmenopausal women indicated no beneficial effect of the medication in treating female androgenetic alopecia.
A 10-year follow-up study of men using finasteride 1 mg daily for androgenetic alopecia reported that better improvements were noted in patients older than 30 years or men who had higher androgenetic alopecia grades. Interestingly, the efficacy of the medication was not reduced with time, and in some cases improved later on. [37]
A Japanese study of 3177 men noted the efficacy and safety of finasteride in the treatment of androgenetic alopecia. Photographs were assessed in 2561 men who completed the 42-month study. Of these men, 11.1% showed great regrowth, 36.5% moderate growth, and 39.5% had a slight increase in hair growth. Adverse effects occurred in 0.7% of the men, and there were no safety problems observed with long-term use. The authors concluded that in Japanese men with androgenetic alopecia, long-term use of oral finasteride maintained progressive hair regrowth without recognized adverse effects. [38]
A retrospective study by Palloti et al indicated that in males with androgenetic alopecia, finasteride treatment can affect sperm and testosterone but is not associated with sexual dysfunction. The investigators found that 6 months after the start of treatment (1 mg finasteride once per day), the total sperm number and percentage of abnormal sperm forms had worsened, while at 12 and 24 months, aside from the percentage of abnormal forms, sperm parameters did not differ. Moreover, results from the International Index of Erectile Function–15 (IIEF-15) did not significantly vary over the course of the study. [39]
Other drugs
Some drugs are not approved by the FDA but are potentially helpful medications. [40] In women with androgenetic alopecia, especially those with a component of hyperandrogenism, drugs that act as androgen suppressants or antagonists (eg, spironolactone, oral contraceptives) may be beneficial. Evidence exists of an association between androgenetic alopecia, hypertension, and hyperaldosteronism. Spironolactone could play a dual role in treatment.
A literature review by Fields et al indicated that topical ketoconazole may provide an effective adjunctive or alternative therapy for androgenetic alopecia. Reports found an increase in hair shaft diameter in association with the agent, and photographic and subjective assessment revealed clinical improvement of the alopecia following treatment. [41]
Dutasteride is another possible treatment for androgenetic alopecia. This drug inhibits type I and type II 5-a reductase isoenzymes and is felt to be 3 times as potent as finasteride in inhibiting the type II enzyme and 100 times as potent in inhibiting the type I enzyme. A phase II study on the use of dutasteride in the treatment of alopecia was carried out in the United States, but no further trials are currently being conducted in the US. However, an ongoing trial is being conducted outside of the United States.
A report by Motofei et al suggested that finasteride is preferable to dutasteride as a therapy for androgenetic alopecia. The investigators stated that finasteride “preserves important physiological roles of dihydrotestosterone” unrelated to androgenetic alopecia and that it appears to have at least partially predictable adverse effects. [42]
A study by Singh et al suggested that botulinum toxin may be a viable treatment for androgenetic alopecia in males, since intramuscular infection of the drug into the scalp results in muscle relaxation and, therefore, increased blood flow. The study included 10 patients, with each of 30 sites in each patients’ scalp injected with 5 U of botulinum toxin. In eight patients, the investigators reported good to excellent results on photographic evaluation. [43]
Low-level laser light therapy, in particular a red light hairbrush–like device has been marketed as an over-the-counter technique for hair growth. In a double blind, sham-device controlled, multicenter, 26-week trial, 110 patients in the active treatment group who completed the study showed a significantly greater improvement in overall hair regrowth than did the sham group. [44] Marketed as the HairMax LaserComb, it has obtained 510K FDA approval for use as a medical device. Note that this approval refers to safety rather than actual efficacy and that the data required for medical devices are quite different from those required to demonstrate the safety and efficacy of drugs.
Topical latanoprost 0.1%, a prostaglandin analogue used to treat glaucoma, has been noted to cause an increase in the number, length, and thickness of eyelashes. Blume-Peytavi et al conducted a 24-week topical treatment with this agent to note the effect on androgenetic alopecia. Sixteen young men with mild androgenetic alopecia were studied. They applied latanoprost 0.1% and placebo daily on 2 minizones on the scalp. Measurements of the hair growth, density, diameter, pigmentation, and anagen/telogen ratio were performed throughout the study. At 24 weeks, an increase in hair density was noted at the latanoprost-treated site compared with baseline and the placebo site. They concluded that this medication could be useful for stimulating hair follicle activity and treating hair loss. [45]
Androgenetic alopecia is very common; therefore, not surprisingly, it may accompany other forms of hair loss. Cases of telogen effluvium often occur in patients with underlying androgenetic alopecia. Therefore, a search for treatable causes of telogen effluvium (eg, anemia, hypothyroidism), especially in patients with an abrupt onset or a rapid progression of their disease, is indicated.
Dawson et al, while discussing female androgenetic alopecia, list the following treatment options to arrest hair loss progression and stimulate partial hair regrowth in this disorder: the androgen receptor antagonists spironolactone and cyproterone acetate, the 5alpha-reductase inhibitor finasteride, and the androgen-independent hair growth stimulator minoxidil. These treatment are most effective when instituted early. [46]
A phase 1, double-blind clinical trial designed to evaluate the safety of a bioengineered, nonrecombinant, human cell–derived formulation containing follistatin, keratinocyte growth factor (KGF), and vascular endothelial growth factor (VEGF) was performed to assess the efficacy in stimulating hair growth. Twenty-six subjects were entered into the study and none showed an adverse reaction to the single intradermal injection. After 1 year, a statistically significant increase in total hair count continued to be seen. [47]
A 2015 study in Spain indicated that plasma rich in growth factors (PGRP) is effective in the treatment of androgenetic alopecia. [48] Over 100 patients were studied and were given two intradermal cycles of PGRF every 4 weeks. Anagen follicles significantly increased by 6.2% compared with baseline, and there was a decrease of 5.1% seen in telogen follicles. No adverse effects were noted in any of the patients.
Serena repens extract has been shown to inhibit both types of 5-α reductase and, when taken orally, has been shown to increase growth in androgenetic alopecia patients. A study by Wessagowit et al attempted to assess the efficacy of topical S repens in androgenetic alopecia. [49] Fifty male patients were studied and were treated with topical S repens products for 24 weeks. The result was that the average hair count increased at 12 and 24 weeks compared with baseline. They believe prolonged use of these products beyond 4 weeks is necessary for sustained efficacy.
Adipose-derived stem cells secrete various growth factors that promote hair growth. Using trichograms, Fukuoka and Suga evaluated the effects of adipose-derived stem cell‒conditioned medium on hair regeneration. [50] The studies were done on patients both on and off finasteride. It was their impression that combination therapy was preferable to single-agent treatment. They believe that using adipose-derived stem cell‒conditioned medium seems to represent a new avenue of therapy for hair regeneration, and they believe that long-term use (over a period of years) should be studied to note effects and histological changes.
Surgical Care
Surgical treatment of androgenetic alopecia has been successfully performed for the past 4 decades. Although the cosmetic results are often satisfactory, the main problem is covering the bald area with donor plugs (or follicles) sufficient in number to be effective. Micrografting produces a more natural appearance than the old technique of transplanting plugs.
A 2009 review of surgical procedures concluded that both patients and physicians alike are pleased with the results of contemporary hair transplantation. [44] Patients with less than 40 follicular units/cm2 in their donor areas are poor candidates for the procedure. Scalp reduction has been attempted to decrease the size of the scalp to be covered by transplanted hair. However, the scars produced by the reduction technique often spread and become more noticeable with time.
Also see the Medscape article Hair Transplantation.
Other Treatments
A South Korean study noted the effect of a 1550-nm fractional erbium-glass laser in women with androgenetic alopecia. The patients received 10 treatments at 2-week intervals. Global photographs taken at baseline and at the end of laser treatment showed improvement in 24 (87.5%) of the 27 patients studied. However, 2 patients reported mild pruritus after treatment. [51]
A literature review by Jedlowski and Anthony indicated that fractionated erbium-glass laser treatment in androgenetic alopecia can increase hair shaft diameter but does not increase hair shaft count. [52]
Hair weaving techniques are available, and, together with hairpieces, they offer the patient a prosthetic method of coverage.
