HAIR DIAMETER IN FEMALE BALDNESS

Summary.— Twenty scalp hairs were plucked from each of 131 Caucasoid women, and measurements of diameter, at 1 mm intervals, starting just above the root, were made for each hair. There was little variation in diameter along normal anagen hairs in any of the subjects. The mean anagen hair diameter in 58 women with diffuse hair thinning, of whom 44 were without detectable endocrine abnormality and 14 were clinically hypothyroid, significantly decreased with age. This appeared to be an accentuation of a normal trend, although this could not be statistically established in the control group of 73 women. At any age the mean thickness of hair in the subjects with diffuse thinning was less than in normal subjects of the same age. Normal subjects showed a symmetrical distribution of hair diameter, with a marked peak at 0.08 mm. In contrast, subjects with diffuse alopecia without detectable endocrine abnormality showed a wide spread of diameters, with 2 equal peaks at 0.04 mm and 0.06 mm The hypothyroid group showed a similar distribution, except that there was a larger proportion of hairs of the smaller diameters. The results suggest that, in the development of diffuse thinning, not all follicles behave identically, and that there may be more than one type of follicle in the human scalp.     

不同年龄成人头发的变化

目的 观察不同年龄成人头发的变化,探讨反映人老化的参照指标.方法 根据入选标准和排除标准征集志愿者,并依据年龄分为4组.头顶指定区域拍照后利用图像分析软件检测头发密度以及黑发率.该区域内随机拔取10根头发,利用目镜测微尺测量发干直径和毛球直径.同时,根据毛囊形态计算不同生长时期毛囊率.结果 共有96名志愿者加入本研究,男44例,女52例,年龄30~78岁.头顶头发密度、毛干直径、毛球直径、生长期毛囊率和黑发率随着年龄的增加逐渐减小,休止期毛囊率及白发率增多,并且60岁以上组明显减小,与其他3个年龄组差异有统计学意义,各组内部分指标存在性别差异.相关分析发现,毛干直径与毛球直径呈显著正相关.结论 头发的一些变化可能作为评价人老化程度的参照指标.     

Androgenetic alopecia in males: a histopathological and ultrastructural study

Background  Androgenetic alopecia is a common cosmetic hair disorder, resulting from interplay of genetic, endocrine, and aging factors leading to a patterned follicular miniaturization. Microinflammation seems to be a potential active player in this process.
Aims  To study the histopathological and ultrastructural changes occurring in male androgenetic alopecia (AGA).
Patients/methods  Fifty-five subjects were included in this study (40 with AGA and 15 as normal age-matched controls). Skin biopsies from frontal bald area and occipital hairy area were subjected to histopathological examination, immunohistochemical staining for collagen I and ultrastructural study.
Results  The frontal bald area of patients showed highly significant increase in telogen hairs and decrease in anagen/telogen ratio and terminal/vellus hair ratio ( P  <   0.001). Perifollicular inflammation was almost a constant feature in early cases and showed a significant inverse correlation with perifollicular fibrosis ( P  =   0.048), which was more marked with thickening of the follicular sheath in advanced cases.
Conclusion  Follicular microinflammation plays an integral role in the pathogenesis of AGA in early cases. Over time, thickening of perifollicular sheath takes place due to increased deposition of collagen, resulting in marked perifollicular fibrosis, and sometimes ends by complete destruction of the affected follicles in advanced cases.     

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.     

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.     

Demonstration of pemphigus-specific immunofluorescence pattern by direct immunofluorescence of plucked hair

Background  Direct immunofluorescence (DIF) of perilesional skin is the gold standard in the diagnosis of pemphigus. Since the outer root sheath (ORS) of anagen hair is structurally analogous to epidermal keratinocytes, pemphigus specific immunofluorescence pattern may be present in the ORS.
Methods  Twenty consecutive patients of pemphigus were enrolled in the study, irrespective of any other inclusion or exclusion criteria. Hairs were plucked in a similar fashion to that of trichogram. Approximately 5 anagen hairs were selected processed and stained with fluorescein isothiocyanate (FITC) conjugates. DIF of perilesional skin and indirect immunofluorescence (IIF) were carried out simultaneously. DIF of hair was also done in equal numbers of controls with other dermatoses.
Results  Intercellular deposition of IgG was seen in the ORS of anagen hair in 85% of patients ( n = 17). The test was positive in all patients who had scalp lesions ( n = 10); however, it was also positive in 7 patients (77.7%) who did not have scalp lesions. The test was negative in 3 patients; two of whom were elderly and had sparse scalp hair. The other patient only had mucosal lesion. The test was negative in the control group.
Conclusion  DIF of hair is a simple, non-invasive test. In future, it may alleviate the need for skin biopsies, in patients with pemphigus.     

Effects of plucking on the anatomy of the anagen hair bulb

Summary The effects of mechanical plucking on the anatomy of human anagen hair bulbs were studied histologically in biopsy specimens taken from scalp areas of ten volunteers immediately after plucking. Anagen hair bulbs were shown to tear off not arbitrarily but in reproducible patterns which include, apart from the typical break conically surrounding the dermal papilla, three additional break forms:(1) rupture of the hair around the upper third of the papilla resulting in so-called dysplastic anagen hairs of the trichogram, (2) rupture of the hair well above the dermal papilla resulting in brocken anagen hairs, (3) total removal of the proximal follicle epithelium with removal of the dermal papilla resulting in so-called papilla hairs of the trichogram. Plucking also gives rise to alterations of the mesenchymal sheath of the hair follicle mainly leading to hemorrhages and a distinct edema entailing an increase in the volume of both the dermal papilla and the underlying papilla cushion of Pinkus. The different break types can be due to inappropriate plucking techniques or may depend on different subphases of the anagen stage.     

Loose anagen hair syndrome in children of Upper Egypt

Background  Loose anagen hair (LAH) syndrome is a phenomenon in early childhood characterized by the presence of easily pluckable hair, where hair tufts can be pulled out easily and painlessly.
Aims  All reports in the English literature described mainly white patients with blond hair. We present the first report of LAH syndrome in dark-skinned children of Upper Egypt.
Patients and methods  Twenty-eight children with LAH were diagnosed and examined from 1996 to 2007. The main complaints were patchy or diffuse alopecia and/or slow growth of hair. Clinical examination, hair pull test, trichogram, and scanning electron microscopy (SEM) were performed.
Results  Children with LAH included 21 girls (75%) and seven boys (25%). Light microscopy of hair pull tests and trichograms disclosed a striking predominance of anagen hairs (90–100%) with misshapen hair bulbs and absent inner and outer root sheaths. SEM confirmed the misshapen anagen bulbs with ruffled appearance of cuticle and the longitudinal groove parallel to the long axis of the hair shaft. Most children improved spontaneously within few years, however, hair shed continued.
Conclusion  LAH syndrome occurs in dark-skinned children and could be under-diagnosed. The condition is of cosmetic concern and does not affect the general health.     

Phototrichogram analysis of Japanese female subjects with chronic diffuse hair loss

Hair growth patterns of 101 Japanese female subjects with diffuse, chronic hair loss and 58 healthy Japanese female volunteers were categorized into subgroups using noninvasive quantitative methods after determining the key parameters of hair growth. Phototrichogram was performed at 0 and 48 h after clipping hairs in the parietal region of the scalp. Shaft diameters of the excised hairs were then measured. Multiple regression analysis indicated that hair densities, hair diameters, short hair ratios, and hair growth rates, but not anagen hair ratios, were significant, in order of decreasing importance, for grading female diffuse alopecia. Using cluster analysis, hair growth patterns among subjects complaining of diffuse hair loss were divided into six abnormal groups (n=60), two borderline groups (n=21), and one normal group (n=20). The control subjects judged to be normal by macroscopic observation, actually included two subjects with borderline hair growth patterns and one abnormal subject. Most of the abnormal groups shared features of female androgenetic alopecia. Hair patterns showing a decrease in hair density but without vellus hair change, however, emerged as the most prevalent and distinct pattern of chronic diffuse hair loss among the Japanese female subjects. The phototrichogram, combined with the measurement of hair diameters, is an accurate tool for assessing hair growth patterns, especially in detecting the slight changes indicative of the early phase of diffuse alopecia.     

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.     

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.     

Finasteride increases anagen hair in men with androgenetic alopecia

BACKGROUND: The growth of scalp hair is a cyclical process of successive phases of growth (anagen) and rest (telogen). In previous clinical trials in men with androgenetic alopecia, treatment with finasteride increased scalp hair counts in a defined area (i.e. increased hair density). OBJECTIVES: The current study used a phototrichogram methodology to assess the effect of finasteride on the phases of the hair growth cycle. PATIENTS/METHODS: Two hundred and twelve men, age 18-40 years, with androgenetic alopecia were randomized to receive finasteride 1 mg daily or placebo for 48 weeks. At baseline and at 24 and 48 weeks, macrophotographs were taken to measure total and anagen hair count in a 1-cm(2) target area of the scalp. RESULTS: At baseline, mean total and anagen hair counts in the finasteride group were 200 and 124 hairs, respectively (% anagen = 62%) and the anagen to telogen ratio was 1.74 (geometric mean). In the placebo group, the respective values were 196 and 119 hairs (% anagen = 60%) and 1.57. At week 48, the finasteride group had a net improvement (mean +/- SE) compared with placebo in total and anagen hair counts of 17.3 +/- 2.5 hairs (8.3% +/- 1.4%) and 27.0 +/- 2.9 hairs (26% +/- 3.1%), respectively (P < 0.001). Furthermore, treatment with finasteride resulted in a net improvement in the anagen to telogen ratio of 47% (P < 0.001). In this study, treatment with finasteride 1 mg day(-1) for 48 weeks increased both total and anagen hair counts, and improved the anagen to telogen ratio. CONCLUSIONS: These data provide direct evidence that finasteride 1 mg daily promotes the conversion of hairs into the anagen phase. These data support that finasteride treatment results in favourable effects on hair quality that contribute to the visible improvements in hair growth observed in treated patients.     

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.     

The anchoring strengths of various chest hair root types

The force required to epilate single chest hairs was measured electronically during a slow (0.09 m/s) machine-driven extraction. Telogen hairs showed a mean anchoring strength of 70 g (s.d. = 16). Anagen hairs, with variable amounts of surrounding root sheaths, had a mean of 71 g (s.d. = 10) whereas bare anagen hairs had a mean of 66 g (s.d. = 13). The catagen phase had a mean of 62 g (s.d. = 8). It is highly likely that the anchoring mechanisms of anagen and telogen roots are as different physiologically as these roots are different anatomically yet both are sufficiently strong to resist the ordinary tractions and pullings to which hair is subject.     

'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.     

Analysis of Microscopic Examination of Pulled Out Hair in Telogen Effluvium Patients

BackgroundTelogen effluvium (TE) is characterized by massive hair shedding and results from an abrupt conversion of anagen to telogen. Differentiation of TE with other hair disorders showing massive hair shedding is difficult.ObjectiveTo evaluate the morphologic characteristics of pulled out hair of TE.MethodsWe analyzed microscopic examination of pulled out hairs by hair pull test in TE patients, and compared these hairs with pulled out hairs in diffuse alopecia areata (AA) patients and healthy volunteers.ResultsHair microscopic examination in 44 TE patients (370 hairs) and 30 healthy volunteers (295 hairs) were as follows: typical club hair, 32.7%, 62.7%; club hair with tail, 23.5%, 23.7%; club hair with remnant sheath, 23.0%, 6.8%; club hair with both tail and remnant sheath, 18.9%, 5.4%; and unclassified hair, 1.9%, 1.4%. The examination in 7 diffuse AA patients (63 hairs) was as follows: typical club hair, 23.9%; atypical club hair, 47.7%; and distinctive AA hair, 28.4%. There was statistical difference between TE patients and healthy volunteers group (p=0.000).ConclusionIncreased atypical club hair in microscopic hair examination might be characteristics of TE.     

A preliminary study of the effect of 11a-hydroxyprogesterone on the hair growth in men suffering from androgenetic alopecia

Ten male patients suffering from androgenetic alopecia were treated during one year with a lotion containing 1% 11a-hydroxyprogesterone. Eight untreated patients served as control group. The parameters used were hair root status, hair shaft diameter of anagen hair roots and number of hairs with a diameter less than 40 micron. After therapy the cranial region showed an increase in the number and mean hair shaft diameter of anagen hair roots and in the number of hair roots with a diameter less than 40 micron. The number of hair roots in catagen/telogen decreased, the number of dysplastic/dystrophic hair roots remained unchanged. After therapy the cranial region in the controls showed a decrease in number and mean hair shaft diameter of anagen roots, and in the number of dysplastic/dystrophic hair roots. There was an increase in number of hair roots in catagen/telogen and of hair roots with a diameter less than 40 micron. The results warrant the conclusion that the above mentioned therapy would seem to be effective in men suffering from androgenetic alopecia.     

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.     

The cross–sectional size and shape of human terminal scalp hair

Change in size of the hair shaft with distance from the scalp has been investigated, using a rotatory profile method of diameter measurement, in terminal human scalp hair of long–haired young Caucasian women. As the whole length of hairs having completed anagen are rarely found intact, two types of hair were investigated: those including segments produced at the onset of anagen (‘anagen hairs’), and those including segments produced at the end of anagen (‘telogen hairs’). In addition, a method of determining the cause of any size variation has been described and employed. Changes were found in the major axis of the hair cross–section, cross–sectional area and ellipticity with distance from the scalp, while the minor cross–sectional axis remained constant. It was established that these changes were the result of intrafollicular rather than extrafollicular mechanisms. Finally, a composite picture of the cross–sectional size and shape of the ‘average’ whole anagen hair of the study has been constructed. From the distal tip towards the scalp for approximately 6–8 cm, there was an abrupt increase in size, representing a starting–up phase of early anagen. Following this, the hair was at its greatest cross–sectional size and ellipticity which then progressively decreased through anagen (20% decrease for cross–sectional area and 13% for ellipticity). In contrast, the minor axis of the hair cross–section, remained constant throughout anagen. The hair was not therefore a uniformly sized cylinder. It was approximately spear–shaped, being broadened out in one plane distally where it was more elliptical. Subsequently as anagen progressed the hair shaft became smaller and more circular.     

Hair diagnoses and signs: the use of dermatoscopy

Background.  Hair-shaft examination is diagnostically useful in a range of adult and paediatric conditions.
Objective.  To evaluate the usefulness of dermatoscopy in hair-shaft microscopy.
Methods.  Typical examples of selected conditions from an extensive collection of scalp hair were examined using a dermatoscope and a light microscope with paired cross-polarizing filters. Hair-shaft characteristics were photographed using a digital camera.
Results.  Dermatoscopy was helpful in detecting tapered hairs, weathering, monilethrix, pediculosis capitis, peripilar casts, 'exclamation-mark' hairs of alopecia areata, bubble hair and pili torti. It was less helpful in pili annulati and unhelpful in detecting 'tiger-tail' banding in trichothiodystrophy. Light microscopy provided greater detail in almost all cases; it was necessary for detection of cuticle changes and added significant information in detecting characteristic features of trichothiodystrophy, pili annulati, bubble hair and pili torti.
Conclusions.  Dermatoscopy is most revealing in conditions resulting in gross changes in shaft outline and colour, where reflected light is valuable. It is unhelpful for detection of features within the shaft or at higher levels of resolution. When added to its ability to aid evaluation of scalp surface characteristics, dermatoscopy provides an excellent first-line method of assessment in clinics. In vivo it may aid screening and selection of hairs of greatest diagnostic yield for further assessment. In some instances, it may obviate the need for obtaining hair specimens and have implications for public health screening. Where detailed or cortical hair-shaft features need assessment, transmitted light microscopy remains the standard tool.