Expression of the L-fucose moiety on infrainfundibular follicular keratinocytes of terminal follicles, its decreased expression on vellus and indeterminate follicles of androgenetic alopecia, and re-expression in drug-induced hair regrowth.

The distribution of various glycoprotein molecules on the surface of follicular keratinocytes was studied with a panel of lectins with specificity for various sugar moieties on biopsy specimens from both bald/balding scalp and normal occipital scalp, of 23 patients with androgenetic alopecia as well as on biopsies of normal forearm skin of four patients. The most significant differences between bald and normal scalp biopsy were noted with Ulex europaeus agglutinin I (UEA I). We noted an increased (91.8% +/- 3.1; mean +/- SE) expression of UEA I binding sites on the infra-infundibular follicular keratinocytes in anagen terminal scalp hairs, compared to 28.5% +/- 5.2 in the indeterminate (anagen) hairs of balding scalps, and 23.2% +/- 6.3 in the anagen follicles of vellus fore-arm hairs. By contrast, the telogen hairs demonstrated minimal UEA I staining: 4.0% +/- 0.8, mean +/- SE in telogen scalp hairs, 1.8% +/- 0.5 in telogen hairs of balding scalps (0% in completely bald scalps, in which all the hairs were in the telogen phase), and 1.9% +/- 0.2 in telogen forearm hairs. The percentage of UEA I staining correlated with the length of the infra-infundibular follicles in all cases studied. In three cases of hair regrowth after hair growth promotors, the UEA I staining increased to 80.6% +/- 6.1 in anagen hairs and correlated with increased length of infra-infundibular follicles. Our data indicate that there are 1) marked differences between anagen and telogen follicles in UEA I binding to infra-infundibular follicular keratinocytes; 2) the percentage of UEA I staining reflects the size (length) of the infra-infundibular hair follicle; and 3) the anagen follicles of balding scalps (indeterminate hairs) show UEA I staining resembling that exhibited by anagen follicles of vellus hairs.     

Changes in hair weight and hair count in men with androgenetic alopecia after treatment with finasteride, 1 mg, daily

BACKGROUND: Finasteride, a type II 5alpha-reductase inhibitor, reduces scalp and serum dihydrotestosterone and has been shown to be effective in men with androgenetic alopecia (AGA). OBJECTIVE: The purpose of this study was to determine the effect of finasteride on scalp hair weight in men with AGA. METHODS: Sixty-six men with AGA received finasteride, 1 mg/d, or placebo in a 48-week study, and 49 men continued in a 48-week extension. Efficacy was assessed by scalp hair weights and hair counts. RESULTS: As expected, hair counts improved with finasteride (net mean percent change +/- SE [95% CI] compared with placebo = 9.2% +/- 2.8% [3.8, 14.6] and 15.4% +/- 3.2% [9.1, 21.7] at 48 and 96 weeks, respectively; P <.01 for both time points), and net improvements in hair weight were greater (25.6% +/- 3.6% [18.5, 32.7] and 35.8% +/- 4.6% [26.7, 44.8] at 48 and 96 weeks, respectively; P <.001 for both time points). Finasteride was generally well tolerated. CONCLUSION: In this study, finasteride, 1 mg, increased hair weight in men with AGA. Hair weight increased to a larger extent than hair count, implying that factors other than the number of hairs, such as increased growth rate (length) and thickness of hairs, contribute to the beneficial effects of finasteride in treated men.     

Measuring reversal of hair miniaturization in androgenetic alopecia by follicular counts in horizontal sections of serial scalp biopsies: results of finasteride 1 mg treatment of men and postmenopausal women

Hair regrowth was evaluated by histologic analysis in men and women treated for androgenetic alopecia, by counting follicles in horizontal sections of scalp biopsies. Serial 4mm punch biopsies were taken at baseline and after 12mo of treatment from the transitional area of hair thinning between normal hair and vertex balding in men, and in an area of frontal/parietal thinning in women. Horizontal sections of reticular and papillary dermis were read by one observer, blinded to patient, treatment, and time. All terminal hair bulbs, terminal anagen and telogen hairs, and vellus and vellus-like miniaturized hairs were counted. Twenty-six men aged 18-41y, comprising 14 on finasteride 1 mg daily and 12 on placebo, and 94 postmenopausal women, aged 41-60y, comprising 44 on finasteride 1 mg daily and 50 on placebo, were evaluated. In the male study, the terminal hairs increased from a mean baseline count of 15.5-20.9 after 12mo of finasteride, versus 17.3-18.3 in the placebo patients. The miniaturized hairs decreased from 26.7 to 23.6 with finasteride versus 21.3-20.3 with placebo. The terminal-to-vellus ratio increased more in the finasteride than in the placebo patients, suggesting some reversal of the miniaturization process with finasteride. In the female study, no significant differences in follicular counts were found between the finasteride and placebo groups after 12mo of treatment. Follicular counts in horizontal sections provide an informative adjunct to noninvasive measures used in hair growth studies. Finasteride appears to be capable of reversing hair miniaturization in androgenetic alopecia in young to middle-aged men, but not in postmenopausal women.     

Melatonin increases anagen hair rate in women with androgenetic alopecia or diffuse alopecia: results of a pilot randomized controlled trial

BACKGROUND: In addition to the well-known hormonal influences of testosterone and dihydrotestosterone on the hair cycle, melatonin has been reported to have a beneficial effect on hair growth in animals. The effect of melatonin on hair growth in humans has not been investigated so far. OBJECTIVES: To examine whether topically applied melatonin influences anagen and telogen hair rate in women with androgenetic or diffuse hair loss. METHODS: A double-blind, randomized, placebo-controlled study was conducted in 40 women suffering from diffuse alopecia or androgenetic alopecia. A 0.1% melatonin or a placebo solution was applied on the scalp once daily for 6 months and trichograms were performed to assess anagen and telogen hair rate. To monitor effects of treatment on physiological melatonin levels, blood samples were taken over the whole study period. RESULTS: Melatonin led to a significantly increased anagen hair rate in occipital hair in women with androgenetic hair loss compared with placebo (n=12; P=0.012). For frontal hair, melatonin gave a significant increase in the group with diffuse alopecia (n=28; P=0.046). The occipital hair samples of patients with diffuse alopecia and the frontal hair counts of those with androgenetic alopecia also showed an increase of anagen hair, but differences were not significant. Plasma melatonin levels increased under treatment with melatonin, but did not exceed the physiological night peak. CONCLUSIONS: To the authors' knowledge, this pilot study is the first to show that topically applied melatonin might influence hair growth in humans in vivo. The mode of action is not known, but the effect might result from an induction of anagen phase.     

Hair counts from scalp biopsy specimens in Asians.

BACKGROUND: Differences in hair density have been described according to the ethnic background in whites and blacks. Asians are known to have fewer hairs than whites. OBJECTIVE: We performed this study to assess the normal values of hair counts in scalp biopsy specimens from Koreans. METHODS: A total of 35 subjects with clinically normal occipital scalps (13 patients with androgenetic alopecia, 20 with patchy alopecia areata, and 2 healthy volunteers) were included. Horizontal sections of 4-mm punch biopsy specimens from clinically normal occipital scalps were examined at various levels from the papillary dermis to the subcutis, and follicular counts of terminal/vellus hairs and anagen/telogen hairs were obtained. RESULTS: The numbers of total hairs, terminal and vellus hairs, and terminal anagen hairs were significantly lower (P <.05) in Koreans compared with the published data of whites and blacks. Percent ratio of terminal anagen and telogen hairs were similar to whites and blacks. Follicular density was significantly lower (P <.05) in Koreans than in whites and blacks. In Koreans, female subjects had a significantly higher number of terminal hairs than male subjects (P <.05). CONCLUSION: Hair density is significantly lower in Koreans than in whites or blacks. Slight sexual difference exists in follicular counts in Koreans. Our data could be used as a guideline for determining normalcy in interpreting horizontal sections of scalp biopsy specimens from Asians.     

African hair growth parameters

BACKGROUND: Hair growth parameters have been studied mostly in caucasian hair, whereas few data on African hair have been reported in the literature. OBJECTIVES: To evaluate hair growth characteristics of African volunteers born in Africa. METHODS: Thirty-eight young adults (19 women, 19 men, mean +/- SD age 27 +/- 10 years), native of central and western Africa, took part in the study. Phototrichograms were performed in order to record three parameters of hair growth: hair density, telogen percentage and rate of growth. For each volunteer, three regions of the scalp, namely vertex, temporal and occipital areas, were assessed. RESULTS: Hair density varied from 90 to 290 hairs cm(-2), with higher counts on the vertex. No significant difference between men and women was recorded. Telogen percentage showed wide variations, from 2 to 46%, with higher levels on the temporal area and in men. The rate of growth fluctuated from 150 to 363 microm day(-1) with no difference related either to gender or to scalp region. These data were compared with those previously obtained in caucasian volunteers of comparable age, and showed significant differences between the two ethnic groups in all three parameters studied. Hair density in African volunteers was lower than that in caucasians (mean +/- SD 190 +/- 40 and 227 +/- 55 hairs cm(-2), respectively). African hair grew at a much slower rate than caucasian hair (mean +/- SD 256 +/- 44 vs. 396 +/- 55 microm day(-1)), and telogen counts were frequently higher in African hair (mean +/- SD 18 +/- 9% vs. 14 +/- 11%). CONCLUSIONS: This study demonstrated significant differences between African and caucasian hair growth parameters, which might suggest a trend towards increased hair loss in Africans, even though it contrasts with a lower and slower incidence of the development of alopecia in Africans.     

The size and form of the medulla of human scalp hair is regulated by the hair cycle and cross-sectional size of the hair shaft

Hairs were sampled from long-haired Caucasian females, and cross-sectional measurements were performed using a rotating profile method at fixed humidity (100%). The effect of the hair cycle on medullation was investigated by examining medulla size and form along the lengths of anagen and telogen terminal hairs and also from a composite model of the entire medulla, as produced from a full cycle's growth, by amalgamating the results from the anagen and telogen hairs. The effect of hair shaft cross-sectional size on medullation has been investigated by controlling any effect of the hair cycle on terminal hairs and by use of the maximal medulla size in short, fine (vellous) hairs from the same subjects. All terminal hairs were medullated for the majority of their lengths. The presence and size of the medulla, in terminal hairs, was profoundly affected by the hair cycle. It was largest early in anagen, where the medulla minor axis, major axis and cross-sectional area represented about 26%, 23% and 7% of the corresponding whole hair shaft parameters (at 100% humidity). The medulla was virtually absent towards the end of anagen. The shape of the medulla cross-section was less elliptical than that of the whole hair shaft and was close to circular. There was no significant change in medulla shape through anagen. The form of the medulla was also affected by the hair cycle; approximately, it was continuous for the first 50% of anagen, discontinuous for the next 25% and virtually absent or absent for the final 25%. The maximal size of the medulla, as occurred in early anagen, was markedly associated with the cross-sectional size of the whole hair shaft, both within terminal hairs and between all scalp hairs. The medulla was large in terminal hairs and small or absent in very small hairs. The proportion of the whole hair shaft occupied by the medulla increased with increase in hair size and reached a maximum in terminal hairs, in which the medulla minor axis represented about 30% of the whole hair shaft minor axis. Furthermore, this proportion was constant in the terminal hairs and was not related to whole hair shaft size. Such maximal proportional medullation might represent a defining feature of terminal hairs. Variation in size of the medulla is not the cause of the previously reported cycle-dependent change in cross-sectional size of the whole hair shaft of terminal hairs.     

Female-patterned alopecia in teenage brothers with unusual histologic features

BACKGROUND: Patterned hair loss, follicular miniaturization, and increased telogen hair counts characterize androgenic alopecia (AGA). Follicular inflammation in AGA has been associated with treatment resistance and progressive hair loss. CASE REPORT: Brothers, 15 and 18 years old, presented with frontal and mid-scalp hair loss with an intact frontal hairline noted over a 1-year period. The elder reported past use of androgenic steroids. Laboratory assessment for metabolic and hormonal abnormalities was unrevealing, and hair pull test was negative. Scalp biopsies revealed decreased terminal hairs, marked diameter variation of anagen hairs, decreased terminal to vellus hair ratios (3.7:1/3.4:1, older/younger), and increased telogen counts (23%/21%). Infrabulbar and peri-isthmic (follicular bulge region) lymphocytic infiltrates were present. Hair loss has progressed, unabated by daily topical 0.5% clobetasol (for 6 months), daily 5% minoxidil (1 year), and latter, daily oral finasteride (2 years - older brother only). DISCUSSION: Based on patterned hair loss and miniaturized hairs, these brothers have AGA. The female pattern of hair loss (diffuse hair loss affecting the central scalp with preservation of frontal hair line) coupled with follicular isthmic lymphocytic inflammation represents an unusual presentation, possibly a treatment resistant, inflammatory variant of AGA. The differential diagnosis includes exogenous androgen-mediated hair loss, cicatricial pattern hair loss, or the superimposition of alopecia areata.     

'Atrophic telogen effluvium' from cytotoxic drugs and a randomized controlled trial to investigate the possible protective effect of pretreatment with a topical vitamin D analogue in humans

BACKGROUND: Hair loss from cytotoxic drugs is classically ascribed to the loss of fractured hairs (anagen effluvium). Telogen hair loss has also been described but some authors have denied any effect on the hair cycle. There are conflicting reports on a protective effect of pretreatment with a vitamin D analogue on cytotoxic drug-induced hair loss in rodents. OBJECTIVES: To investigate the process of cytotoxic hair loss and any protective effect on the hair of pretreatment with topical calcipotriol. METHODS: Breast cancer patients who were about to receive cycles of chemotherapy with cyclophosphamide 600 mg m(-2), methotrexate 40 mg m(-2) and 5-fluorouracil 600 mg m(-2) were recruited and randomized to receive calcipotriol scalp solution 50 microg mL(-1) or vehicle. The solution was applied twice daily from 4 days prior to chemotherapy and continued for 14 days in each treatment cycle. Shed, plucked and cut hairs were sampled. Absolute shed rates, the proportion of major hair types, the presence of proximal hair shaft changes, regrowth (using the new anagen hair count) and hair density were assessed. RESULTS: Ten patients receiving calcipotriol and 14 receiving vehicle completed three treatment cycles and nine from both groups completed six cycles. There was no detectable effect of calcipotriol on the proportion of patients experiencing minimal hair loss from chemotherapy, shed rates, plucked telogen and fractured hair counts, the morphology of shed and plucked hair, hair regrowth or hair density. Combining results of the treatment groups, there was a large variation in the impact of chemotherapy on hair loss, from total loss in five patients to no obvious loss in five. Excluding the latter, during chemotherapy shed telogen hairs (mean 81% of shed hairs) predominated over fractured (12%) and anagen hairs (6%) (P = 0.0002). The major pathological change was proximal hair shaft tapering, baseline mean 3% of shed hairs rising to 48% (P = 0.0005) during treatment, and there was a consequent decrease in normal telogen hairs, baseline mean 98% of all telogen hairs falling to 55% (P = 0.0005) during treatment. The pathological tapered telogen hairs had normal or small, sometimes diminutive, bulbs. Fracturing of hairs with diminutive bulbs produced typical 'exclamation mark' hairs. CONCLUSIONS: The cardinal effects of cytotoxic drugs found in this study were tapering of the proximal hair shaft and premature entry of the follicle into telogen, conflicting with the conventional view that affected hair follicles continue in anagen. There was a resulting effluvium of a mixture of tapering telogen hairs and fractured hairs. As entry into telogen is an integral part of the process, cytotoxic hair loss may be regarded as a variant of the conventional 'telogen effluvium' and we propose the term 'atrophic telogen effluvium'. There was no obvious protective effect on the hair loss of prior treatment with topical calcipotriol.     

Histologic response to topically applied minoxidil in male-pattern alopecia

The histopathology of androgenetic alopecia is characterized by reductions in follicular size and mean hair shaft diameter without significant reduction in follicular density.¹ The proportion of hairs found in anagen is diminished with a corresponding increase in hairs in normal telogen, plus a marked increase in a persistent stage of telogen. The telogen germinal unit is the term given by Headington² to the structure that represents a persistence of telogen after shedding of the club hair but in which anagen has not been re-established.

Regrowth of scalp hair following topical application of minoxidil has been demonstrated in both primates^3,4 and humans^5,6 suffering from androgenetically determined alopecia. As part of a nationwide multicenter trial of topical minoxidil in male-pattern alopecia, scalp biopsy specimens were obtained before and after treatment to determine what histopathologic changes might be found and if this might help us understand the way in which the clinically observed regrowth of hair might occur.     

Characterization of dermal type I collagen of C3H mouse at different stages of the hair cycle

Hair follicles develop or regress in accordance with the hair cycle. In this study, we partially characterized fibrillar type I collagen, the predominant component in the dermis, at two stages of the hair cycle: anagen and telogen. Skin samples were obtained from the backs of two groups of 11-week-old C3H mice: one at anagen stage induced by shaving and the other at telogen stage. The amount of neutral salt-soluble (newly synthesized) collagen obtained from anagen skin was about twofold that from telogen skin, while the level of acid-soluble collagen was not significantly different between the two groups. The degree of lysine hydroxylation of pepsinized type I collagen obtained from anagen skin was significantly higher than that in telogen (5.0% higher in alpha1 chain, and 15.6% higher in alpha2 chain). Proline hydroxylation at the anagen stage was also slightly higher than in the telogen stage. Two major collagen cross-links were found in both groups of skin; dehydro-hydroxylysinonorleucine and dehydro-histidinohydroxymerodesmosine. The concentration of the latter, a complex tetravalent cross-link, was significantly lower in anagen skin when compared with telogen skin (mean +/- SD 0.64 +/- 0. 07 vs. 0.78 +/- 0.06 mol/mol collagen). The former showed no significant difference between the two groups. In addition, a significant amount of lysyl-aldehyde (a cross-link precursor) was found in anagen (0.16 +/- 0.02 mol/mol collagen), while it was 0.12 mol/mol collagen in telogen. These results indicate that the remodelling of collagen is more active in anagen skin than in telogen, and that characteristic post-translational modifications of dermal collagen seen in anagen may play a part in facilitating an environment around hair follicles for their migration and growth.     

Progression of hair loss in men with androgenetic alopecia (male pattern hair loss): long-term (5-year) controlled observational data in placebo-treated patients

Relatively little is known about the progression of androgenetic alopecia (AGA; male pattern hair loss) in untreated men. We evaluated the long-term (5-year) progression of AGA in men treated with placebo in a controlled clinical trial setting. We analyzed pooled data over 5 years from two replicate studies with finasteride 1 mg/day in men with predominantly vertex-pattern AGA. Each study consisted of an initial 1-year, randomized, double-blind, placebo-controlled base study and four consecutive, 1-year, double-blind, placebo-controlled extension studies. Change over time in scalp hair growth was evaluated by four predefined endpoints: scalp hair counts; assessment of standardized clinical photographs by an expert panel; investigator clinical assessment; and patient self-assessment. All four predefined endpoints demonstrated progressive scalp hair loss in men receiving placebo over the 5-year study period, with a loss of 239 hairs from baseline (26.3% decline in hair density) measured in the target area at 5 years (p < 0.001 vs. baseline). Similarly, visible progression of scalp hair loss was demonstrated by global photographic assessment, with 75% of placebo patients rated as worsened from baseline at 5 years. We found that scalp hair loss continued in a progressive manner over a 5-year period in placebo-treated men with AGA.     

Finasteride improves male pattern hair loss in a randomized study in identical twins.

OBJECTIVES: This study compared the efficacy of finasteride with placebo in the treatment of male pattern hair loss (androgenetic alopecia) in nine pairs of male identical twins. METHODS: In this randomized, double-blind, placebo-controlled, single-center study, one twin from each identical twin pair received finasteride 1 mg/day for one year while the other received placebo. Hair growth was evaluated from standardized clinical photographs, hair counts and patient self-assessment questionnaires. Serum dihydrotestosterone and testosterone levels were analyzed and adverse events recorded. RESULTS: Finasteride significantly improved hair growth at one year compared to placebo (p < 0.05) based on analysis of photographs of the vertex and superior-frontal scalp. These results were consistent with the hair count change measured in the finasteride group, which was superior (p < 0.05) to the change measured in the placebo group. Patient self-assessment demonstrated that treatment with finasteride, in comparison to placebo, led to improvements in scalp hair growth and patients' satisfaction with appearance of hair. No drug-related adverse events were reported during the study. CONCLUSION: Through the use of identical twins, this study provides further evidence that finasteride significantly reduces hair loss progression and restores hair growth in men with male pattern hair loss.     

Objective evaluation of photoepilation by phototrichogram

Photoepilation is one of the most popular cosmetic procedures. However, there has been no objective method to evaluate the efficacy of hair removal. The goal of this study is to evaluate the effect of photoepilation more objectively using a phototrichogram method. Thirteen young, healthy, female volunteers were enrolled in this study. At initial work-up, semi-permanent tattoos were marked in both axillae of all the volunteers and hair variables were evaluated by phototrichogram and digital camera. Intense pulsed light-assisted photoepilations were performed in both axillae of the volunteers twice at 4-week intervals. At each visit, dermatologists checked changes of hair parameters. Clinically, 8 weeks after two treatments, hair reduction of all patients was achieved. Total hair counts, changes of anagen ratio, non-vellus hair counts, hair density, anagen growth rate and hair diameter were decreased sequentially and the reduction was statistically significant. No correlations were found between power, pain, patient and doctor evaluations at 4 weeks. Doctor evaluations correlated with anagen hair counts, anagen/total hair ratio, anagen/telogen ratio and total growth rate. Using phototrichograms could be an objective evaluation technique for hair removal. Anagen parameters and total growth rate of hairs in phototrichograms may be able to be predictable values for evaluating epilation.     

Proposal and evaluation of a Monte Carlo model for hair regrowth following plucking

Background/aims: The efficacy of single or multiple hair removal treatments reveals a number of properties of the hair follicle, such as the phase in the growing cycle and the hair growth speed. The aim of the present study was to provide a method to evaluate the results of hair removal treatments, in particular plucking, in order to obtain insight into some properties of the follicle and to propose a strategy for optimal treatment. Our hypothesis is that plucking of anagen hairs may result in either reset of the follicle to telogen, in mild damage to the follicle, resulting in a temporary reduction of the mitotic activity, or in an unaffected follicle, so that the hair continues to grow. Methods: The regrowth of hairs after plucking was measured as a function of time for a number of subjects. Individual leg hairs within the areas observed were followed over time. Besides this, the growth speed of leg hairs was measured, and the extracted anagen hair length was determined to obtain an estimate of the anagen follicle depth on the leg. Monte Carlo simulations of the hair plucking and regrowth process were performed after the experiments. Some parameters derived from the experiments were used as inputs; others were fitted to achieve a good correlation between the result of the simulations and the experiments. Finally, the Monte Carlo routine was used to investigate the influence of the time interval between multiple plucking treatments. Results: The regrowth of hairs after plucking, the growth speed and the extracted anagen hair length were measured. Both experiments and Monte Carlo simulations indicated that the result of plucking of an anagen hair is not limited to reset of the follicle to telogen or continued hair growth, but that a temporary reduction of the mitotic activity is very likely to occur. Finally, a linear relationship between the interval between epilation treatments and the average number of hairs on the skin was found using the Monte Carlo simulation. Conclusions: The combination of experiments and Monte Carlo simulations is a very successful strategy for studying hair removal and hair (re)growth in detail.     

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.     

TrichoScan: a novel tool for the analysis of hair growth in vivo

Hair loss or hair thinning is a common complaint in clinical dermatology, and patients seeking advice for hair loss are not necessarily bald. Because the effects of treatment attempts are hard to measure, there is need for a sensitive tool to monitor hair loss and treatment responses. Such a method must be able to analyze the biologic parameters of hair growth, which are: (i) hair density (n per cm2); (ii) hair diameter (microm); (iii) hair growth rate (mm per day); and (iv) anagen/telogen ratio. Herein we present the TrichoScan as a method that combines epiluminescence microscopy with automatic digital image analysis for the measurement of human, and potentially animal hair, in situ. The TrichoScan is able to analyze all four parameters of hair growth with a so-called 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 is demonstrated by comparing the hair parameters in individuals without apparent hair loss, men with untreated androgenetic alopecia, and men after treatment with finasteride (1 mg per day). We were able to detect a significant increase in hair counts and cumulative hair thickness 3 and 6 mo after treatment. Advantages of the TrichoScan are that it can be used for clinical studies to compare placebo versus treatment, to compare different capacities of hair growth promoting substances, to study androgenetic alopecia and other forms of diffuse hair loss, and to study the effects of drugs and laser treatment on hypertrichosis and hirsutism.     

Alopecia areata incognita: a hypothesis

To explain why in alopecia areata the hair falls out in a particular area the hypothesis is proposed that the area occurs as a stochastic event only in those subjects who, in a restricted zone of their scalp, happen to have a group of hairs that are simultaneously in the early anagen VI subphase of the hair cycle. Once this point has been accepted, a number of conclusions may be drawn. Especially important is the inference that only people with low percentages of telogen hairs are likely to exhibit areas, whereas those with androgenetic alopecia, when affected by alopecia areata, preferentially show a diffuse and delayed hair loss that has the features of Kligman's telogen effluvium (alopecia areata incognita). Epidemiological evidence is provided.     

Hair counts in scalp biopsy of males and females with androgenetic alopecia compared with normal subjects

Background:  Hair counts were studied in scalp biopsy specimens of androgenetic alopecia (AGA) in male and female patients. We also assessed the normal value of hair count in scalp biopsy specimen from Iranians and compared with published data.
Methods:  Thirty subjects with clinically normal scalps, 25 male and 28 female patients with AGA were studied. Vertical and horizontal sections of 4-mm punch biopsy specimens were examined at various levels from the papillary dermis to the subcutis. Hair counts of total, terminal, vellus, anagen and telogen hairs were obtained by ocular micrometer.
Results:  Hair counts were not significantly different from published data in American Whites but significantly higher in Iranians compared with Koreans (p < 0.001). There was no significant difference between male and female patients with AGA. Perifollicular inflammation was lower in both the normal subjects and the patients compared with other studies.
Conclusion:  In AGA patients, total and vellus hairs were lower and terminal to vellus (T:V) ratio was higher than the results of previous studies in Whites (p < 00.1). T:V ratio of control group was significantly higher in this study compared with previous published data. Perhaps the higher ratio than the reported data could means the onset of miniaturization.     

Permanent alopecia after systemic chemotherapy: a clinicopathological study of 10 cases

Anagen effluvium due to chemotherapy is usually reversible with complete hair regrowth. However, there is increased evidence that certain chemotherapy regimens can cause dose-dependent permanent alopecia. The histological features of this type of alopecia and the mechanisms of its origin are not known yet. We discuss the histological features of 10 cases of permanent alopecia after systematic chemotherapy with taxanes (docetaxel) for breast cancer (6 patients), busulfan for acute myelogenous leukemia (3 patients), and cisplatin and etoposide for lung cancer (1 patient). All patients had moderate to very severe hair thinning, which in 4 cases was more accentuated on androgen-dependent scalp regions. Patients complained that scalp hair did not grow longer than 10 cm and showed altered texture. Paired scalp biopsies from the affected scalp areas were obtained and evaluated in serial horizontal and vertical sections. The histology of all specimens was characterized by a nonscarring pattern with a preserved number of follicular units and lack of fibrosis. The hair count revealed decreased number of terminal hairs, increased telogen hairs, and increased miniaturized vellus-like hairs with a terminal to vellus and anagen to telogen ratios of 1:1 and 3.6:1, respectively. There was increased number of fibrous streamers (stelae) in both reticular dermis and subcutis. Arao-Perkins bodies were found in the subcutaneous portions of the streamers. The histological findings of permanent alopecia after chemotherapy are those of a nonscarring alopecia similar to androgenetic alopecia. Dermatopathologists should be aware of this condition as the absence of fibrosis and the presence of miniaturized hairs may be considered as features consistent with a diagnosis of androgenetic alopecia. Hence, these cases could easily be misdiagnosed in the absence of a good clinicopathological correlation.