Trichoscan: what is new?

The treatment of androgenetic alopecia (AGA) is usually long lasting, and the effects of treatment attempts are difficult to measure. Consequently, there was a need for a sensitive tool to monitor hair loss and treatment response. Therefore, we developed the Trichoscan as a method which combines epiluminescence microscopy with automatic digital image analysis for the measurement of human hair. The Trichoscan is able to analyze all important parameters of hair growth (density, diameter, growth rate, vellus and terminal hair density) with an intraclass correlation of approximately 91% within the same Trichoscan operator and an intraclass correlation of approximately 97% for different Trichoscan operators. The application of the technique was demonstrated by comparison of the hair parameters in 9 men with frontal balding which were treated for 6 months with 5% minoxidil. Even in this small cohort of patients, we noticed after 3 months of treatment compared to baseline a significant increase in hair density (+21.3 hairs/cm2; p = 0.047) and cumulative hair thickness (+0.61 mm; p = 0.008) and after 6 months a significant increase in hair density (+34 hairs/cm2; p = 0.011) and cumulative hair thickness (+0.88 mm; p = 0.010). The study shows that the Trichoscan has many advantages. It can be used for clinical studies to compare placebo versus treatment or to compare the relative potencies of different hair-growth-promoting substances. It can be used for studying AGA or other forms of diffuse hair loss, and it can be adopted to study the effect of drugs or laser treatment on hypertrichosis or hirsutism. The drawbacks, however, are that the Trichoscan still needs a hair dye for contrast enhancement and the measurement area must be clipped before analysis. This mini-review summarizes recent attempts to optimize the technique and shows new options such as the calculation of follicular units or the 'anagen hair count'.     

Scalp immersion proxigraphy (SIP): an improved imaging technique for phototrichogram analysis*

In recent years we have developed the concept of using automated computer assisted image analysis (ACAIA) for hair growth evaluation. The success of this sophisticated technology depends on the quality of the original images that are fed into the mainframe of the image analyzer. Application of immersion oil onto the scalp site to be photographed appears to improve contrast between hair and scalp and has been named ‘Scalp Immersion Proxigraphy’ (SIP) in contrast to crude proxigraphy, that is close-up photography without application of immersion oil, commonly used for phototrichogram analysis (PT). In this paper, we report evidence indicating that besides the qualitative improvement of the image, SIP also contributes to generate more accurate quantitative data. Such a conclusion was reached after hair growth variables were compared as a function of the photographic method (SIP vs. PT: 16 scalp sites; 5 balding subjects with clinical features consistent with androgen dependent alopecia). Each site was photographed with both techniques immediately after clipping and 48 h later. After image recording, we manually re-processed the original pictures on transparencies. The original pictures and the transparencies were analyzed with ACAIA. There was a significant difference between methods in terms of evaluation of linear hair growth rate (LHGR; mm/day, n= 1332 bairs; Scheffe F-test, P < 0.05). LHGR recorded with re-processed SIP pictures (0.317 mm/day) was very close to that measured in our laboratory with micrometric methods. Distorted figures were generated by PT, leading to an underestimation of this parameter by 30% on average (0.224 mm/day). From previous studies, we knew that hair diameter correlates with linear hair growth rate: the thinner the hair fiber, the slower the growth rate. Both variables may be considered as additive in terms of severity of the alopecia. In this comparative trial of two phototrichogram techniques, we showed that linear hair growth rates can only be accurately estimated with SIP. Therefore, SIP should be used instead of crude proxigraphy when a global assessment of hair growth is to be monitored during clinical trials.     

Recent findings with computerized methods for scalp hair growth measurements

Sensitive tools have been developed in order to monitor hair loss and treatment responses. Recently the Tricho-Scan was presented (by RH) as such a method which combines epiluminescence microscopy (ELM) with automatic digital image analysis. Herewith new TrichoScan data obtained from 10 women and 21 men with androgenetic hair loss after 6 mo of treatment with 5%-minoxidil are presented. Even in this small cohort of patients, we noticed a significant increase of hair density, cumulative hair thickness and terminal hair counts. Alternative methods were developed during a human alopecia investigation and research technology (HAIR Technology) programme at Skinterface. This involves contrast-enhancement, image acquisition, and processing by qualified technicians followed by computer-assisted image analysis. The specific identification of exogen hair, further adds to this very refined non-invasive investigative method for hair follicle function investigation. Regional variations of hair growth dynamics do exist in the human scalp such as in female patients complaining of hair loss, scalp hair density and growth on top of the head differs significantly from the occipital site. Finally, from transversal studies and from detailed monitoring of subsequent hair cycles during longitudinal studies, data were obtained that support the fact that shortening of hair cycle, slowing down of growth rates and thinning of hair shafts are heralding hair miniaturisation. In the workshop the TrichoScan, the method of Canfield and Skinterface have been shown.     

Hypertrichosis in females applying minoxidil topical solution and in normal controls

BACKGROUND: Hypertrichosis has been reported more frequently in females than in males who use minoxidil topical solution (MTS) for the treatment of androgenetic alopecia (AGA). This article examines the occurrence of MTS-induced hypertrichosis in females. METHODS: Data from placebo-controlled clinical trials in females (up to 5% MTS) were analysed based on spontaneous reports of hypertrichosis/facial hair and investigators' inquiries (solicited) about the presence of any new hair growth on body parts other than the scalp. A postmarketing drug surveillance database for MTS was also examined for reports of hypertrichosis/facial hair. RESULTS: In the clinical trials involving a total of 1333 females, spontaneous reports of hypertrichosis/facial hair were noted for 50 (4%) females in a dose-related pattern of response (5% MTS > 2% MTS > placebo). Nine females (seven and two in the 5% MTS and 2% MTS groups, respectively) discontinued treatment because of hypertrichosis/facial hair. Solicited reports of excessive hair growth (primarily facial) also showed a dose-related pattern of response. Post-marketing data showed a lower occurrence (0.5%) of hypertrichosis/facial hair than in the clinical trials. Of interest, in one clinical trial, 27% of the females enrolled (MTS and placebo treated) had facial hair growth reported at baseline. CONCLUSIONS: Females with some hirsutism are particularly prone to seek treatment for AGA, and this may explain the high occurrence of hypertrichosis/facial hair found in the MTS clinical trials. Furthermore, some demographic groups of females are prone to develop facial hair and the problem of unwanted facial hair growth seems to be underestimated. Some females may have hair follicles that are very sensitive to MTS and should use the lowest strength of MTS (2%) to help avoid unwanted hair growth. The hypertrichotic effect of MTS on other sites than the scalp, including the face, is reversible and does not always require discontinuation of therapy.     

Topical minoxidil in male pattern baldness: effects of discontinuation of treatment

Ten men with male pattern baldness who had been treated with 2% or 3% minoxidil for at least 4 months were evaluated for any changes in scalp hair growth on and off drug. Objective assessments by hair counts showed a mean doubling of nonvellus target scalp hairs on topical minoxidil and loss of most of these recruited hairs when the drug was discontinued. Four of ten men had nonvellus hair counts off topical minoxidil that fell below baseline levels. Thus, hair growth on topical minoxidil is not sustained when the drug is discontinued.     

Quantification of hair follicle parameters using computer image analysis: A comparison of androgenetic alopecia with normal scalp biopsies

Computer image analysis enables large numbers of hairs to be measured in an automated fashion. In this study, we examined horizontal scalp biopsies from 10 patients with a histological diagnosis of androgenetic alopecia and 10 normal control subjects. The density of hair follicles and the ratio of terminal to vellus hairs were determined. Hair shaft, hair canal and hair follicle diameter, inner root sheath width and outer root sheath area were measured using the Chromatic Colour Image Analysis program. This study showed a statistically significant progressive decrease in size of hair canal diameters from normal terminal hairs (85.93 ± 10.07 μm) through to androgenetic alopecia terminal (68.83 ± 13.60 μm) and vellus hairs (28.67 ± 5.60 μm). This pattern is also seen with hair follicle diameters; normal terminal (268.41 ± 24.88 μm), androgenetic alopecia terminal (236.34 ± 17.23 μm), and vellus hairs (130.88 ± 19.96 μm). Outer root sheath areas, hair shaft diameters and ratio of terminal to vellus hairs were significantly larger in normal (18500 ± 4222 μm²; 82.71 ± 13.79 μm; 36:1; respectively) compared with androgenetic alopecia scalp biopsies (8403 ± 3322 μm²; 61.11 ± 14.42 μm; 3:1; respectively), whereas inner root sheath width and density did not vary significantly. Computer image analysis can be adapted for use in clinical trials where large numbers and objectivity are critical in determining the efficacy of hair growth promoters.     

Thickness, medullation and growth rate of female scalp hair are subject to significant variation according to pigmentation and scalp location during ageing

The biological importance and/or significance of human hair colour is unknown even though greying is obviously associated with ageing. In order to further characterise hair pigmentation in relation with hair growth variables we evaluated 3 scalp sites (top of the head (T): left and right and occipital(O)) in 12 untreated menopausal women (age range: 49-66 years: average 59.63 +/- 5.66) who presented complaining of hair loss and/or diffuse alopecia. Controls were 12 non menopausal sexually mature woman (7 age range 15-21 and 5 age range 38-48) not complaining of hair loss. One hair sample (whenever possible n = 60) was taken one month after clipping from T and O on each person; menopausal women were sampled twice. The following measures were performed with a light microscope: diameter (average min-max., microm), medulla (0% = absent to 100% = fully developed) and linear hair growth rate (mm/day). The hairs were categorised as pigmented (P) or non-pigmented (white, W) as compared with a black and white reference card. A total of 3343 hairs were analysed with 2-factor analysis of variance (ANOVA). A global comparison (all hairs) showed that the average diameter of W hair (67.68 microm) exceeded that of P hair (57.41 microm) (p = 0.0001) and this was maintained on all 3 scalp sites. In addition, the medulla of W hair (23.91%) appeared more developed than the medulla of P hair (12.21%) (p = 0.0001) and was more expressed in W T hairs as compared with W O hairs (p = 0.0325). There was also a significant interaction between site and pigmentation (p = 0.0074). Growth rate of W hairs (0.38 mm/d) was higher than that of P hairs (0.35 mm/d) (p = 0.0001) and there was a significant variation according to scalp sites (p = 0.0001). There was also a significant interaction between site and pigmentation (p = 0.0062) with the following rank order: O W (0.40 mm/d), T W (0.37 mm/d), O P (0.37 mm/d) and T P (0.34 mm/d). Subgroups of W and P of paired thickness in the range of 50 to 80 pm consistently showed a 10% faster growth rate of W. Previous studies have shown that growth rate and diameter declines in age and alopecia i.e. in hair thinning. Our data shows that the reduced growth rate of terminal hairs is in fact limited to the pigmented hairs. The mechanisms by which white hairs are spared these ageing changes are not yet understood. Less pigmented hairs are usually undetected by photo- graphic techniques used for drug trials. The potential role of drug induced modifications of hair pigmentation should be taken into account during the interpretation of efficacy except if contrast-enhancement has been applied.     

Advances in the treatment of male androgenetic alopecia: a brief review of finasteride studies

Finasteride is a type 2 5a-reductase inhibitor and therefore mimics the biochemical profile of inherited type 2 5a-reductase deficiency in men. It was developed to grow hair in androgenetic alopecia and shrink benign prostatic hyperplasia. Various clinical trials of finasteride have confirmed its beneficial effects in androgenetic alopecia in males, but not in females. It can produce visible hair growth in up to 66% of men with mild to moderate alopecia, but importantly can stop hair loss in 91% of patients. In long-term finasteride studies, placebo patients were characterized by significant and progressive hair loss. It can be concluded that finasteride prevents further hair loss by actually continuing to grow enough hair to preserve scalp coverage. This is confirmed by the loss of hair following withdrawal of finasteride in such cases. The proven preservative effect of finasteride, in addition to its restorative effect, is a strong indication for prescribing it in early cases of androgenetic alopecia before much hair has been lost.     

Improvement in scalp hair growth in androgen-deficient women treated with testosterone: a questionnaire study

Background Androgens are thought to have an adverse effect on female scalp hair growth. However, our clinical experience of androgen replacement therapy in women with androgen deficiency, in which hair loss was seldom reported, led us to question this concept. Objectives To evaluate the effect of subcutaneous testosterone therapy on scalp hair growth in female patients. Methods A total of 285 women, treated for a minimum of 1 year with subcutaneous testosterone implants for symptoms of androgen deficiency, were asked to complete a survey that included questions on scalp and facial hair. Age, body mass index (BMI) and serum testosterone levels were examined. Results Out of the 285 patients, 76 (27%) reported hair thinning prior to treatment; 48 of these patients (63%) reported hair regrowth on testosterone therapy (responders). Nonresponders (i.e. no reported hair regrowth on therapy) had significantly higher BMIs than responders (P = 0·05). Baseline serum testosterone levels were significantly lower in women reporting hair loss prior to therapy than in those who did not (P = 0·0001). There was no significant difference in serum testosterone levels, measured 4 weeks after testosterone implantation, between responders and nonresponders. No patient in this cohort reported scalp hair loss on testosterone therapy. A total of 262 women (92%) reported some increase in facial hair growth. Conclusions Subcutaneous testosterone therapy was found to have a beneficial effect on scalp hair growth in female patients treated for symptoms of androgen deficiency. We propose this is due to an anabolic effect of testosterone on hair growth. The fact that no subject complained of hair loss as a result of treatment casts doubt on the presumed role of testosterone in driving female scalp hair loss. These results need to be confirmed by formal measurements of hair growth.     

Contrast enhanced phototrichogram (CE-PTG): an improved non-invasive technique for measurement of scalp hair dynamics in androgenetic alopecia--validation study with histology after transverse sectioning of scalp biopsies

Global changes of scalp hair represent the cumulative end result of discrete changes of individual hair follicle structure and/or function. Monitoring of such changes requires an accurate non-invasive method. The phototrichogram (PTG) appears to be an appropriate choice to do so. However, a known weakness of the method is the lack of detection of less pigmented or thinning hair. Balding scalp of male subjects with androgenetic alopecia (AGA) was analysed with our previously published PTG method and with contrast enhanced (CE-)PTG followed by biopsy and transverse section examination with the light microscope. As compared with PTG, the CE-PTG method significantly improved detection not only of thin but also of thick hair. Equal numbers of thick (diameter > 40 mm) hair were detected with CE-PTG and with histology. CE-PTG was also able to detect the severely miniaturised hair fiber (down to 8 mm diameter) and was comparable to scalp biopsy analysis. The latter could identify hair fibres, which did not reach the scalp surface, a measure that is considered as not clinically significant. All growth stages - anagen, catagen and telogen - as well as the empty follicle stage could clearly be observed with CE-PTG. Staging of the more severely affected hair follicles was not always possible neither with CE-PTG nor histology - even with serial sectioning. The finding of such technological advantages makes the CE-PTG a first choice method for detailed analysis of hair cycling in androgenetic alopecia - a scalp disorder characterised by extreme hair follicle miniaturisation, decreased hair pigmentation and hair thinning.     

Treatment of chemotherapy-induced alopecia

Chemotherapy-induced alopecia has been well documented as a cause of distress to patients undergoing cancer treatment. Despite the importance of hair loss to patients, however, patients often receive little more counseling than the advice to purchase a wig or other head covering for the duration of their treatment. Research into non-camouflage (wigs, turbans, and head scarves) treatment methods has been complicated both by a lack of a standardized methodology for evaluating hair loss and hair regrowth and by a lack of human trials. Nevertheless, scalp cooling as a method of preventing hair loss during chemotherapy and 2% topical minoxidil as a therapy for accelerating regrowth after chemotherapy are both effective non-camouflage options for treatment. Other proposed treatments for prevention of hair loss during chemotherapy have demonstrated promise in early trials, but these findings will need validation from rigorous further studies. The increasing number of reports of permanent alopecia not just with pre-bone marrow transplant, high-dose busulfan, and cyclophosphamide regimens but also with standard breast cancer chemotherapy regimens illustrates the importance of further research into treatment methods for chemotherapy-induced alopecia.     

Finasteride treatment of patterned hair loss in normoandrogenic postmenopausal women

BACKGROUND: Finasteride, an inhibitor of type 2 5alpha-reductase, inhibits conversion of testosterone to dihydrotestosterone, resulting in a decrease in serum and scalp dihydrotestosterone levels believed to be pathogenic in androgenetic alopecia. Oral finasteride has been shown to be effective in the treatment of hair loss in men, while its efficacy in women has remained controversial. METHODS: 5 postmenopausal women without clinical or laboratory signs of hyperandrogenism were given 2.5 or 5 mg/day oral finasteride for the treatment of pattern hair loss. Efficacy was evaluated by patient and investigator assessments, and review of photographs taken at baseline and at months 6, 12 and 18 by an expert panel. RESULTS: Finasteride treatment improved scalp hair by all evaluation techniques. The patients' self-assessment demonstrated that finasteride treatment decreased hair loss, increased hair growth and improved appearance of hair. These improvements were confirmed by investigator assessment and assessments of photographs. No adverse effects were noted. CONCLUSIONS: Oral finasteride in a dosage of 2.5 mg/day or more may be effective for the treatment of pattern hair loss in postmenopausal women in the absence of clinical or laboratory signs of hyperandrogenism.     

TrichoScan as a method to determine hair root pattern in patients with scalp psoriasis

Scalp involvement is a prominent and often the initial presentation in patients with psoriasis. Hair growth may be impaired with a hair loss and an increased telogen/anagen ratio. The aim of this study was to investigate the hair density and anagen/telogen ratio in psoriatic patients, using epiluminescence microscopy combined with digital image analysis (TrichoScan). Thirty psoriatic patients with scalp involvement and the same number of clinically healthy individuals were included in the study. For the measurement of hair density, anagen/telogen ratio and number of terminal and vellus hairs, a commercially available software TrichoScan was used. Hair density measurements did not show significant difference between patients and controls (P=0.05). The anagen ratio was significantly lower and telogen ratio significantly higher in psoriasis patients than in controls (P<0.01 both). There was no correlation between hair parameters and patient age or duration of disease. Study results support the evidence that scalp psoriasis is associated with an increased telogen/anagen ratio.     

The therapeutic use of topical minoxidil

Topical minoxidil is a trichogenic agent that stimulates the hair follicle via the vasoactive metabolite minoxidil sulfate without any evidence of antiandrogen activity or an effect on the immune system. Less than 5% of the applied dose is absorbed. The therapeutic effect on hair regrowth is demonstrated for androgenetic alopecia in males and females, by a computer-assisted image analysis counting technique of nonvellus hairs from a photographic print. Patients with severe alopecia areata respond poorly to topical minoxidil treatment. The most common adverse reactions are limited to irritant and allergic contact dermatitis on the scalp. The use of retinoic acid with topical minoxidil has been disappointing relative to the increase in systemic exposure. The value of topical minoxidil as an adjunct for the hair transplant procedure and its effect on hair loss from chemotherapy are being evaluated.     

The hair root pattern in psoriasis of the scalp.

Several reports suggest that a localized effluvium of scalp hair may occur in patients with psoriasis. The percentages of telogen and catagen hair have been claimed to be normal or increased in isolated cases. In the present study the anagen/telogen ratio was quantified under standardized conditions in psoriatic plaques and uninvolved areas of the scalp in 22 patients and the scalp of 22 normal controls. This assessment was carried out by light microscopic analysis of hair roots, obtained by the hair pluck-method. A consistent increase in the percentages of telogen and catagen hair was shown in psoriatic plaques, compared with the uninvolved areas. Compared with the scalp of normal controls, this percentage was significantly increased in psoriatic plaques, but not in the uninvolved areas.     

Human eyelash characterization

Background Few biological data on human eyelash follicles have been reported in the literature. Objectives To characterize eyelash follicle growth, cycle and morphology, and further investigate the biological mechanisms that determine eyelash length, curl and pigmentation, compared with scalp hair follicle. Methods Twenty‐nine caucasian female volunteers aged between 26 and 60 years were enrolled in the study to provide eyelashes. Four of these volunteers were followed weekly for 9 months to characterize their eyelash cycle. Eyelash length and time of renewal were measured using a high‐resolution camera and image analysis. Immunohistological study of the bulbs were performed on eyelid biopsies from 17 patients requiring block excision for ectropion repair. Results The calculated durations of anagen phase and complete cycle of the eyelashes were 34 ± 9 and 90 ± 5 days, respectively. Eyelash follicle growth rate was quite variable, with an average rate of 0·12 ± 0·05 mm daily. Eyelash follicle morphology was very close to that of the scalp hair follicle, but some remarkable differences were noticed. For example, the K19‐positive epithelial stem cell population was spread all along the follicle and not split into two reservoirs as seen in scalp hair follicles. Some asymmetry was detected in HSPG and CSPG, as well as K38 (formerly Ha8) and K82 (formerly Hb2) distribution, similar to that observed in curly hair. Finally, dopachrome tautomerase was found expressed in eyelash follicle melanocytes, while it was strikingly absent in scalp hair follicle melanocytes. Conclusions The eyelash is structurally very close to curly hair but some biological processes related to follicle cycle and pigmentation differ markedly.     

Hair shaft abnormalities in alopecia areata evaluated by optical coherence tomography

Background/purpose: Optical coherence tomography (OCT) is able to provide highly reproducible measurements of hair shaft thickness, including hair shaft diameter, cross‐sectional surface area and hair shape, similar to histology but in vivo. Variations in the caliber of hair shafts have been described in patchy hair loss like alopecia areata (AA) using electron microscopy. The aim of this study was to evaluate whether OCT is useful for the evaluation of hair shaft abnormalities in AA. Methods: The measurements were performed on patients with AA (n=9), aged 2–66 years. Fifty hairs from the border of an alopecic area and 50 hairs from an unaffected area without hair loss were examined using the OCT technique. The hair parameters were characterized by the cross‐section (CS) and the form factor. The ratio of the maximal and minimal diameters of the hair at a fixed measuring distance from the scalp surface determined the form factor (d_max/d_min). Results: In all cases, the CS of hairs from an AA patch was significantly lower compared with hairs of an unaffected area. However, the form factor did not indicate any disturbances in hair growth. Conclusions: The results demonstrate that structural abnormalities of hair shafts are found in active lesions of AA, but not in clinically unaffected hairs. The OCT technique is a promising method to gain more insight into the pathogenesis of AA in a non‐invasive way.     

Simulation and analysis of optical skin lesion images

BACKGROUND/PURPOSE: In order to properly analyse the effectiveness of methods for optically differentiating malignant from benign skin lesions, it is necessary to have a set of images for which the ground truth is known. However, aspects of the ground truth of clinical images such as true lesion boundary position are unknown or not known precisely. Therefore, a skin/lesion image simulation with known features including boundary location, skin pattern and lesion colour is needed to enable accurate assessment of feature estimation algorithms for lesion classification. METHODS: In this paper, monochrome and colour skin/lesion images are synthesised with known characteristics including boundary, colour and skin pattern. Skin pattern is simulated with segmented lines with variations in length, orientation and intensity. Skin and lesion textures are modelled by an auto-regressive (AR) process. Monochrome skin lesion images are obtained by combining monochrome skin and lesion textures under the control of a known lesion shape with the addition of skin pattern. Colour skin lesion images are generated by mixing coloured skin and lesion textures. Finally, an inflammation area and image artefacts such as hair and specular reflection are added. RESULTS: The synthesised images provide the image set for evaluating image pre-processing, segmentation and skin pattern analysis. The pre-processing includes hair removal and specular reflection reduction. An AR model interpolation is suggested for hair removal, and multiple illumination processing is developed to decrease specular reflection. A fast snake algorithm is extended to detect the boundaries of skin lesion and inflammation areas. Skin line direction is detected as a feature to measure the disruption of skin pattern caused by lesion. CONCLUSIONS: Simulation of monochrome and colour skin/lesion image has been investigated, which is an alternative way to provide image set with known characteristics to validate image processing algorithms for image pre-processing, lesion/inflammation boundary detection and skin pattern analysis.     

The effects of finasteride on scalp skin and serum androgen levels in men with androgenetic alopecia.

BACKGROUND: Data suggest that androgenetic alopecia is a process dependent on dihydrotestosterone (DHT) and type 2 5alpha-reductase. Finasteride is a type 2 5alpha-reductase inhibitor that has been shown to slow further hair loss and improve hair growth in men with androgenetic alopecia. OBJECTIVE: We attempted to determine the effect of finasteride on scalp skin and serum androgens. METHODS: Men with androgenetic alopecia (N = 249) underwent scalp biopsies before and after receiving 0.01, 0.05, 0.2, 1, or 5 mg daily of finasteride or placebo for 42 days. RESULTS: Scalp skin DHT levels declined significantly by 13.0% with placebo and by 14.9%, 61.6%, 56. 5%, 64.1%, and 69.4% with 0.01, 0.05, 0.2, 1, and 5 mg doses of finasteride, respectively. Serum DHT levels declined significantly (P <.001) by 49.5%, 68.6%, 71.4%, and 72.2% in the 0.05, 0.2, 1, and 5 mg finasteride treatment groups, respectively. CONCLUSION: In this study, doses of finasteride as low as 0.2 mg per day maximally decreased both scalp skin and serum DHT levels. These data support the rationale used to conduct clinical trials in men with male pattern hair loss at doses of finasteride between 0.2 and 5 mg.     

Finasteride in the treatment of men with frontal male pattern hair loss

Background: Finasteride, a specific inhibitor of type II 5α-reductase, decreases serum and scalp dihydrotestosterone and has been shown to be effective in men with vertex male pattern hair loss. Objective: This study evaluated the efficacy of finasteride 1 mg/day in men with frontal (anterior/mid) scalp hair thinning. Methods: This was a 1-year, double-blind, placebo-controlled study followed by a 1-year open extension. Efficacy was assessed by hair counts (1 cm² circular area), patient and investigator assessments, and global photographic review. Results: There was a significant increase in hair count in the frontal scalp of finasteride-treated patients (P < .001), as well as significant improvements in patient, investigator, and global photographic assessments. Efficacy was maintained or improved throughout the second year of the study. Finasteride was generally well tolerated. Conclusion: In men with hair loss in the anterior/mid area of the scalp, finasteride 1 mg/day slowed hair loss and increased hair growth. (J Am Acad Dermatol 1999;40:930-7.)