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.     

瘢痕性女性型脱发1例

报道1例瘢痕性女性型脱发。患者女,36岁,因脱发加重十余年就诊。皮肤科检查：弥漫性头发稀疏,发质细软,可见多数铅笔橡皮擦样大小的灶性秃发区。TrichoScan检查提示额部毛发密度明显降低,毛发直径变异度大于20%,毳毛比例明显增加。毛发镜检查：毳毛增加,可见大量直径3 ~ 5 mm的灶性秃发区域,部分毛囊开口消失,可...     

Characteristic features of Japanese women's hair with aging and with progressing hair loss

BACKGROUND: There have been few studies of the features of hair with aging and hair loss in Japanese women. OBJECTIVE: Features of Japanese women's hair with aging and with progressing hair loss were investigated. METHODS: Japanese women with hair loss (n=46) or with no or less hair loss (n=113), aged 14-68 years, were studied. Severity of hair loss was rated by visual comparison with six standard photographs. Hair density, hair growth rate, and hair diameter were analyzed by phototrichogram. Follicular units were deduced by a non-invasive method using tree-view analysis on scalp imaging. RESULTS: Hair loss in Japanese women is commonly characterized by a diffuse central pattern occurring after approximately 40 years of age. Hair density declines with age after the 40s. The reduction resulted from an increase in the number of one-haired follicular units and a reduction of three- and more-haired follicular units. Both the ratio and the growth rate of anagen hair also declined with age after the 40s. Mean hair diameter and the ratio of thick hairs increased with age from about 10 to 40 years, and decreased with progressing hair loss. There were few vellus-like hairs in women with hair loss, in comparison with male-pattern baldness. CONCLUSION: In Japanese middle-aged women, hair density declined with age without the appearance of hair loss. Hair loss appeared after approximately 40 years of age. The major causes might be reduction of hair density and the ratio of thick hairs, but not an increase of vellus-like hairs.     

Hair density, hair diameter and the prevalence of female pattern hair loss

BACKGROUND: Female pattern hair loss is common but estimates of its prevalence have varied widely. The relationships between the clinical diagnosis of female pattern hair loss and objective measurements of hair density and hair diameter have not previously been evaluated. OBJECTIVES: To determine the prevalence of female pattern hair loss and to relate the clinical findings to hair density and hair diameter. METHODS: We examined 377 women, aged 18--99 years, who presented to a general dermatology clinic with complaints unrelated to hair growth (the unselected sample). A second group of 47 women referred with typical female pattern hair loss was included in analyses of the relationships between hair density, hair diameter and the clinical diagnosis. Hair density was measured using a photographic method. In each subject the major and minor axis diameters were measured in a random sample of 50 hairs. RESULTS: Six per cent of women aged under 50 years were diagnosed as having female pattern hair loss, increasing to 38% in subjects aged 70 years and over. The mean +/- SEM hair density was 293 +/- 61.3 hairs cm(-2) at age 35 years, falling to 211 +/- 55.1 hairs cm(-2) at age 70 years. Hair density showed a normal distribution in the unselected sample. Most women classified as having female pattern hair loss had hair densities within the lower half of the normal distribution. The perception of hair loss was determined mainly by low hair density (ANOVA P < 0.001), but there was overlap in hair density between women classified as having Ludwig I hair loss and the no hair loss group, which was partly accounted for by differences in mean hair diameter (ANOVA P < 0.001). Low hair density was associated with fewer hairs of all diameters. CONCLUSIONS: Hair density in women is distributed as a normal variable, indicating that it is determined as a multifactorial trait. Women with female pattern hair loss have a hair density which falls below the mean but lies within the spectrum of the normal distribution, although other factors, including hair diameter, may affect the subjective impression of hair loss. The hair diameter data suggest that low hair density is not due to progressive diminution in hair follicle size and that follicular miniaturization may occur within the space of a single hair cycle.     

Topical minoxidil therapy in hereditary androgenetic alopecia

A randomized double-blind trial of topical minoxidil therapy was carried out on 56 patients with hereditary male pattern baldness. The subjects selected were required to have a discernible balding patch, a minimum of 2.5 cm in diameter on the vertex of the head where the hairs could be counted and photographed. Minoxidil, 1.0 mL, was applied twice a day to the scalp beginning at the balding vertex and spreading centrifugally around the scalp. Cosmetically acceptable hair growth was achieved in 18 patients (32%). The most notable indicators for regrowth of hair were the number of indeterminate hairs initially present, the duration of baldness, and the size of the balding area. No serious systemic or cutaneous side effects were noted.     

Quantitative assessment of 2% topical minoxidil in the treatment of male pattern baldness

Forty-seven men with male pattern baldness were treated in a double-blind clinical trial with topical 2% minoxidil or placebo. Twelve were randomly selected for quantitative hair measurement using the unit area trichogram and visual counting. There was no significant difference after 6 or 12 months of treatment with a 2% minoxidil solution for total hair density (THD; hair cm-2), meaningful hair density (MHD; hair greater than 40 microns in diameter greater than 30 mm in length cm-2), per cent of hair in the anagen growth phase, or the per cent of meaningful hair in the anagen growth phase. Significantly fewer hairs were recorded with the visual hair counting method, compared to values obtained from adjacent sites with the unit area trichogram. In addition, a significantly larger mean total hair count was recorded by an experienced observer, compared to an inexperienced observer. Increased pigmentation was observed within the vellus hair population of treated subjects. Our findings indicate that minoxidil appears unlikely to affect the long-term course of male pattern baldness. However, we found no significant deterioration in total hair density, or meaningful hair density in treated subjects, suggesting minoxidil may have a prophylactic effect. Further long-term studies employing the unit area trichogram are required to evaluate this finding.     

A Comparative Study of Axillar Hair Removal in Women: Plucking versus the Blend Method

Fourteen healthy adult Japanese females were selected to participate in a comparative study of hair plucking (a temporary hair removal technique) and the blend method (a permanent hair removal technique). The effectiveness of permanent hair removal and the safety of the blend method were examined in this study. If hairs of the left axilla were removed by the blend method, then hairs of the right axilla were removed by plucking, and vice versa. Every hair was removed and the number of hairs was counted each time. Sessions were conducted every three weeks, and the experiment continued until no new hair growth was seen using the same experimental standard. Electrologists with more than 1000 hours of experience were selected to perform electrolysis. Examinations of the axilla, before and after each test, were conducted by the authors. The results showed that the number of hairs decreased in the axilla with each session using the blend method: permanent hair removal was achieved in an average of 26.8 weeks or 9.9 sessions. However, the number of hairs did not decrease in the axilla after plucking. Also, there were no reports of hair removal related side-effects in this study. It was thus demonstrated that the blend method is a safe and effective way of achieving permanent hair removal.     

Transplants from balding and hairy androgenetic alopecia scalp regrow hair comparably well on immunodeficient mice

Human hair follicles were grafted onto 2 strains of immunodeficient mice to compare the regeneration potential of vellus (miniaturized, balding) and terminal (hairy, nonbalding) follicles from males and a female exhibiting pattern baldness. Each mouse had transplants of both types of follicles from a single donor for direct comparison. Grafted follicles from 2 male donors resulted in nonsignificant differences in mean length (52 mm vs 54 mm) and mean diameter (99 microm vs 93 microm) at 22 weeks for hairs originating from balding and hairy scalp, respectively, corresponding to 400% versus 62% of the mean pretransplantation diameters. Follicles from the female donor transplanted to several mice also resulted in nonsignificant differences in length (43 mm vs 37 mm) for hairs from balding and hairy scalp, respectively, during a period of 22 weeks. The mean diameter of the originally vellus hairs increased 3-fold, whereas the terminal hairs plateaued at approximately 50% of pretransplantation diameter, resulting in a final balding hair volume double that of the nonbalding hairs. This report shows that miniaturized hair follicles of pattern alopecia can quickly regenerate once removed from the human scalp and can grow as well as or better than terminal follicles from the same individual.     

Qualification of a new and precise automatic tool for the assessment of hair diameters in phototrichograms

Background/purpose: To automatically assess hair growth during cosmetic trials, incorporating parameters such as anagen‐to‐telogen rate, growth rate, and especially hair diameter. Methods: We designed and qualified a new and automatic phototrichogram system based on a high‐resolution DSLR camera system (theoretical resolution of 2.557 μm/pixel) and modular macrolens system with fixed focus, combined with a trainable pattern recognition software for automated analysis. Results: We improved the standard routine for dermatological phototrichogram technique to overcome inaccuracy in thickness measurements due to hair swelling by using an alternative immersion fluid, and increased the effective resolution for hair size and thickness measurement to <4 μm. After having qualified manual measurements as gold standard for the determination of hair diameters, we established a new trainable automatic picture analysis software able to locate and measure individual hairs in length and thickness even in picture series taken from the same skin area at different time points. Comparisons between manual and automatic measurements of the same hairs showed a >90% correlation, and by comparing the automatic results with manual measurements of the same images without individual hair annotation, we could find a correlation of at least 80%. Conclusion: According to the results and findings generated in this qualification study, we have a reliable tool now that enables us to test cosmetic products for hair treatment in a highly automated way with a sufficient degree of precision and accuracy to detect even small changes in hair diameter during cosmetic trials.     

Natural progression of male pattern baldness in young men

Twenty-six men who presented with male pattern baldness (androgen-dependent alopecia), were quantitatively evaluated for scalp hair variables and compared with 13 age-matched controls. Compared to controls, significant mean differences for hair variables were found in the frontal-vertex area, while in the occipital area, a reduction in total hair density (hairs/cm2) was the only significant (P less than 0.05) finding. A large proportion (48.5%) of meaningful hair (non-vellus hair) was less than or equal to 40 mm in length, yet had diameters similar to hairs growing much longer. In controls, these hairs accounted for only 12.2% of the total population. Compared to baseline, mean values from the frontal-vertex area of subjects with androgen-dependent alopecia were significantly lower for total hair density, meaningful hair density (non-vellus hairs/cm2) and percentage of hair in the anagen growth phase, 12 and 24 months later. During this time, total hair density decreased by 6.5% after 12 months and by 11.9% after 24 months. Similarly, meaningful hair density declined at 12 months by 10.8% and by 22.7% after 24 months. No change in any hair variable was detected in controls after 12 or 24 months. Our findings suggest that medications capable of maintaining the existing hair population should be regarded as effective treatments for this condition. Left untreated androgen-dependent alopecia progressively deteriorates. The induction of non-vellus hairs less than or equal to 40 mm in length to grow longer, would substantially improve the aesthetic profile without the need to generate new hair.     

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.     

Usefulness of TrichoScan professional in the evaluation of hair loss in females. Report of 180 cases

Background TrichoScan Professional is a computerized program used for digital measurement of hair growth and hair loss. The aim of our study was to undertake an evaluation with TrichoScan Professional of female patients consulting at our hospitals for hair loss. The purpose of our study was to determine whether TrichoScan was able to identify differences in hair parameters that would correlate with the pattern of alopecia or according to the age of the patients evaluated. Material and methods One hundred‐eighty women that consulted consecutively for loss of hair were included. Patients were aged between 8 and 85 years (mean age 36 years). Data including age, the number of hairs, hair density per square centimetre, anagen and telogen percentage and percentage of terminal and miniaturized hair were analysed. Results Results observed with TrichoScan were as below: number of hairs (mean 154.9; range 34–316). Hair density per square centimetre (mean 239; range 52–486). Hair in anagen phase (mean 62.4%; range 9–93%). Hair in telogen phase (mean 37.4%; range 7–91%). Terminal hair (mean 95.2%; range 82–100%). Vellus hair (mean 4.7%; range 0–17%). Pearson′s correlation test was used to measure the strength of the association of age with the rest of parameters. The statistical analysis showed a significant correlation between age and both the number of hairs and the hair density per square centimetre. However, no significant correlation between age and rest of the parameters was observed. Conclusions TrichoScan Professional may help to quantify hair density and in our sample, this was the only parameter showing a significant decrease according to age in various types of alopecia affecting the females.     

Effective medical treatment for common baldness in women

Endocrine profiles were established in nineteen women, aged 18–43 years, with common baldness. Reduced plasma levels were found in SHBG (68%), luteal phase progesterone (52%) indicating sub-fertility, LH (42%), oestradiol (37%) and FSH (21%), while plasma total testosterone was raised in only one patient. Three women with a history of diffuse loss of scalp hair of 2, 13 and 23 years duration and a familial history of premature balding in two, were treated with cyclical antiandrogen therapy (CAT) for 52 weeks. All showed an increase in hair density (hairs/cm²), and in the number of hairs greater than 40 um diameter/cm² (meaningful density) after 24–28 weeks. The percentage of hairs in the anagen growth phase increased during therapy. Three control patients, left untreated for 26 weeks, showed no significant improvement in hair density, meaningful density or the percentage of hair in the anagen growth phase. During CAT, each patient showed an increase in plasma SHBG and a fall in plasma testosterone levels. One patient with severe depressive symptom related to hair loss prior to therapy, returned to a normal way of life without the need for psychotropic drugs.     

Dry dermoscopy in clinical treatment of alopecia areata

Although dermoscopy is conventionally utilized with immersion gel for diagnosis of pigmented tumor, we utilized dry dermoscopy, which is dermoscopy without immersion gel, for clinical treatment of alopecia areata (AA). The scalp skin and hair of a 38-year-old Japanese male, and 23-, 22- and 47-year-old Japanese females with AA, whose normal hair color was black, were examined by dry dermoscopy. Exclamation mark hairs, short hairs, fractured hairs and black dots, all characteristic of AA, were detected by dry dermoscopy of the scalp of the 23-year-old female with ophiasis type AA. In the case of the 47-year-old female with round hair loss on the occipital scalp and diffuse hair loss over the fronto-vertical region, dry dermoscopy was useful for diagnosis of AA based on hair characteristic of AA. After she received corticosteroid pulse therapy with 500 mg of i.v. methylprednisolone on 3 successive days, her hair showed apparent regrowth and disappearance of the abnormal hairs characteristic of AA, evidenced by dry dermoscopy 1 month later. In a case of long-lasting AA in the 23-year-old female, we found a follicular plaque-like appearance at the opened hair follicle pores by dry dermoscopy. Histopathologically, the incompletely differentiated remnant hair shaft was packed in the follicular infundibulum. In addition, regrowing vellus hairs, which were difficult to clinically recognize, were detected by dry dermoscopy. Dry dermoscopy is therefore useful for both diagnosis and follow up of AA.     

Topical adenosine increases the proportion of thick hair in Caucasian men with androgenetic alopecia

Adenosine is an effective treatment for androgenetic alopecia (AGA) in Japanese men and women. Adenosine exerts its effects by significantly increasing the proportion of thick hair. In this study, we assessed the clinical outcome of adenosine treatment for 6 months in 38 Caucasian men. The change in proportion of thick hair (≥60 μm) compared with baseline in the adenosine group was significantly higher than that in the placebo group (P < 0.0001). The change in vellus hair proportion (<40 μm) was significantly lower in the adenosine group than that in the placebo group (P = 0.0154). The change in hair density compared with baseline of the adenosine group was also significantly higher compared with that of the placebo group (P = 0.0470). No adverse effects due to treatment were noted during this study by dermatological evaluation. Adenosine is effective in increasing the proportion of thick hair in Caucasian men with AGA as well as in Japanese men and women.     

雄激素源性脱发分型等级的主客观分析

目的为运用计算机图像分析结合临床评价建立融合主客观信息的中国人雄激素源性脱发(androgeneticalopecia,AA)分型系统提供依据,使长期应用形态学图案的主观评估上升至主客观相结合,可以更精确、更真实地评估毛发的脱落或生长.方法①收集目前临床上应用较多的经典的AA分型等级图,运用计算机图像分析以及SPSS分析软件的统计分析,证实各分型模式和图像分析计算的头发遮盖率(hair covering rate,HCR)之间存在良好的相关性.②用病例验证计算机图像分析结果和临床评判结果之间的相关性.结果除了Ludwig分型外,所有分型模式等级和HCR之间都具有很好的相关性(P＜0.01).对AA病例的图像以Hamilton分型等级图为标准进行的临床评估和图像分析得到的结果与上述分析结果一致.结论以临床分析结果和图像分析计算的HCR的良好相关性为基础,可以进一步应用图像分析计算出毛发密度、直径、外形、长度和生长速率等定量信息,并结合主观临床分析建立中国人AA分型系统.     

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.     

Biomechanical properties of human hair with different parameters

Background/purpose: Investigations on the mechanical properties of human hair are inadequate. This research explores the break force of anagen hair by forming criteria according to the diameter of hair, gender, age, strain, use of drugs and hair dyes and how these criteria affect the mechanical resistance of hair.
Methods: The resistances of anagen hair of 120 volunteers were investigated in our biomechanics laboratory. The relationship between the value of break force of hair and hair diameter, gender, age, strain, use of drugs and hair dyes was examined. Tensile tests were applied to each hair with a 50 N load cell device.
Results: The statistical evaluation demonstrated a significant difference between the break forces of hairs with different hair diameters. The hairs with a diameter of 51 μm and above had a significantly higher break force than those of 50 μm and below ( P =0.000). An insignificant correlation was observed between break force and strain ( P =0.554, r =−0.055) whereas the correlation between diameter and strain was statistically significant ( P =0.000, r =0.361).
Conclusion: The break force of hairs did not show any significant dependency on age, presence of hair dyes, gender and usage of drugs. Yet, a statistically significant difference was observed between the break forces of hairs when compared according to their diameters and strain. More research on the mechanical properties of human hair consistent with biological properties like protein structure, α keratin fibers and microfibril–matrix composite behaviors would guide dermatologists for diagnostic symptoms.     

Acquired progressive kinking of hair. Report of six cases and review of literature

Acquired progressive kinking of hair is an entity distinct from woolly hair in its onset at or after puberty, predominant involvement of frontal, temporal, and vertex regions of the scalp as well as the supra-auricular and postauricular margins, and a tendency for affected hairs to resemble pubic hair both in texture and color. We consider the condition to be androgen dependent and likely to progress to male pattern baldness. The condition "whisker hair" is probably a variant of acquired progressive kinking of hair.     

Long-term outcome of a patient with paradoxical hypertrichosis after laser epilation

One underreported, rare side effect of laser hair removal is paradoxical hypertrichosis. It is largely unknown what the long-term outcomes are of patients who develop this complication. We report a 21-year-old, Fitzpatrick II, male patient, who had patchy areas of dark hair affecting various body areas. An Alexandrite 755 nm laser was used to address the desired areas at energies between 20 and 22 J/cm² at 10–12-week intervals over a course of seven treatments. After three treatments, the patient noted a significant increase in the density and length of hairs involving the back, shoulders, neck, and upper arms. The patient was followed on a biannual basis, without further epilatory intervention. After 10 years, the areas of paradoxical hair growth were sparser compared to immediate post-treatment but remained denser compared to pre-treatment. This case illustrates improvement in the condition over time without intervention. Further studies are needed to determine the etiopathogenesis of this phenomenon.