Characteristic findings by phototrichogram in southern Chinese women with Female pattern hair loss

Assessment of Occipital Involvement Among a Large Population of Females with Pattern Hair Loss in Saudi Arabia

Background

Cumulative evidence suggests the involvement of the occipital region in female pattern hair loss (FPHL). However, most of the studies that have been published so far concerned relatively small samples of patients.

Purpose

To assess the occipital involvement in FPHL and analyze its correlation with disease severity among a large sample of patients.

Patients and Methods

A retrospective study involved 1000 adult women with FPHL, between January 2020 and August 2022. Occipital involvement was defined as more than 10% of thin hairs (<0.03 mm). Baseline trichometry parameters in the frontal and occipital regions were analyzed.

Results

Occipital involvement was observed in 32.4% of the patients. Positive correlations between frontal and occipital regions were observed for all trichometry parameters; the strongest concerned average hair shaft thickness (Pearson's coefficient r=0.708), cumulative hair thickness (r=0.673), and trichometry-derived Sinclair scale (r=0.656). The risk of occipital involvement increased independently with the disease severity in frontal region; however, the disease progression was slower in the occipital compared to frontal region.

Conclusion

One-third of females in our study with FPHL had occipital involvement. This has a major impact on the methods used to diagnose pattern hair loss in females and their treatment plan including hair restoration surgery.

Recent Advances in Understanding of the Etiopathogenesis, Diagnosis, and Management of Hair Loss Diseases

Hair-loss diseases comprise heterogenous conditions with respective pathophysiology and clinicopathological characteristics. Major breakthroughs in hair follicle biology and immunology have led to the elucidation of etiopathogenesis of non-scarring alopecia (e.g., alopecia areata, AA) and cicatricial alopecia (e.g., lichen planopilaris, LPP). High-throughput genetic analyses revealed molecular mechanism underlying the disease susceptibility of hair loss conditions, such as androgenetic alopecia (AGA) and female pattern hair loss (FPHL). Hair loss attracted public interest during the COVID-19 pandemic. The knowledge of hair loss diseases is robustly expanding and thus requires timely updates. In this review, the diagnostic and measurement methodologies applied to hair loss diseases are updated. Of note, novel criteria and classification/scoring systems published in the last decade are reviewed, highlighting their advantages over conventional ones. Emerging diagnostic techniques are itemized with clinical pearls enabling efficient utilization. Recent advances in understanding the etiopathogenesis and management for representative hair diseases, namely AGA, FPHL, AA, and major primary cicatricial alopecia, including LPP, are comprehensively summarized, focusing on causative factors, genetic predisposition, new disease entity, and novel therapeutic options. Lastly, the association between COVID-19 and hair loss is discussed to delineate telogen effluvium as the predominating pathomechanism accounting for this sequela.

Evaluation of Scalp Hair Density and Diameter in the Arab Population: Clinical Office-Based Phototrichogram Analysis

Background

Knowing normal values of scalp hair thickness and density is beneficial for diagnosing hair disorders, monitoring responses to therapy, performing hair transplants, and conducting relevant research. Such normal values have not yet been studied for Arabs.

Objective

To assess the hair density and diameter of the Arab population at different scalp sites using phototrichogram.

Methods

A cross-sectional descriptive study was performed at King Saud University Medical City from December 2021 to August 2022. The study was conducted on Arab adults who were not suffering from any hair disorder. The study was conducted using a questionnaire and clinical examination by phototrichogram.

Results

A total of 120 participants were enrolled in this study. The mean hair density was 147.1± 7.8 hairs/cm2, and the mean hair diameter was 87±4.9 μm. There were significant differences between hair density (P=0.0001) and diameter (P=0.0001) in different regions of the scalp. Females had higher hair density than males at occiput (P=0.038).

Conclusion

Arab hair has a higher thickness and lower density than hair of other ethnicities. This needs to be considered when diagnosing and/or treating hair problems in Arabs.

The Predictive Value of Midscalp Hair Density and Terminal Hair Percentage in the Severity Evaluation of FPHL Assessed by Trichoscan in a Sample of Chinese Population

BACKGROUND

Female pattern hair loss (FPHL) is the most common hair loss disorder in women, which may impair patient's self-identity. It presents as a diffuse reduction in hair density at the mid and frontal regions of the scalp with preservation of the frontal hairline. TrichoScan can be used as a diagnostic tool and for monitoring patients in male pattern hair loss, but little is known in FPHL with Chinese population.

OBJECTIVE

To explore the predictive value of various TrichoScan characteristics at different areas of the scalp in the diagnosis and evaluation of FPHL.

MATERIALS AND METHODS

A total of 261 FPHL subjects were divided into three groups according to Ludwig classification. Together with 108 healthy controls, they were evaluated by computer-assisted TrichoScan. Various hair parameters were analyzed in the frontal, midscalp, vertex, parietal, and occipital areas of the scalp.

RESULTS

Declining hair densities, terminal hair percentage, hair follicular unit density, mean hair diameter, and average hair/unit combined with increased intermediate hair percentage, and vellus hair percentage were observed across all areas of the scalp for FPHL subjects. Hair density and terminal hair percentage in the midscalp area were the factors most affecting Ludwig classification. The two parameters combined achieved 85.12% correct classification rate and an area under the ROC curve of 0.88 in the diagnosis of FPHL. Additionally, we reported a unique type of FPHL which mostly affected the parietal area, occurring with or without traditional midline changes.

CONCLUSION

FPHL in a Chinese population presented characteristics of reduced hair density and miniaturization of hair follicles in the midline scalp and to a lesser extent in the parietal area. Hair density and terminal hair percentage in the midscalp exhibited the greatest predictive value of Ludwig classification. Our results may further provide the basis for quantitative classification of FPHL.

Comparison Between Trichoscopic and Histopathological Evaluations of Hair Parameters

Background

Collecting data on hair counts helps dermatologists diagnose hair diseases more accurately. Quantitative trichoscopy analysis and pathologic examination are two common ways to evaluate hair parameters.

Purpose

The study aims to compare the effect of quantitative trichoscopy analysis and pathologic examination in hair counting and quantify the hair density of average Chinese people.

Methods

Trichoscopy was performed in four scalp regions with a total of twenty-three volunteers without alopecia: frontal, vertex, occipital, and parietal. Hair density parameters were recorded. A 4-mm punch biopsy was performed in the occipital area, and all specimens were transversely sectioned serially and observed to calculate the hair densities.

Results

The average hair density, hairs per follicle unit, and vellus hair ratio from quantitative trichoscopy analysis in the occipital region were 163.07±28.17/cm², 1.87±0.25 and 6.60±3.95%, lower than those from biopsy significantly (214.97±48.73/cm², 2.24±0.30 and 10.48±6.43%). The hair shaft diameter measured by quantitative trichoscopy analysis was 74.52±8.02μm, higher than that by histopathologic examination (68.65±8.00μm) (p<0.05).

Conclusion

Quantitative trichoscopy is a noninvasive, quick, and convenient way to evaluate hair density. Histopathologic examination is an invasive way but provides more accurate data. The data obtained from trichoscopy and pathological examination are different to some extent, which cannot be substituted entirely for each other. This study established the reference for hair density in the adult Chinese population.

Variation of Hair Follicle Counts among Different Scalp Areas: A Quantitative Histopathological Study

INTRODUCTION

Scalp biopsy is a standard method for the definitive diagnosis of alopecia. The hair count parameters of each scalp area remain unclear. This study aimed to determine hair count values at different scalp locations from histopathology and to establish reference values for each part of the scalp.

METHODS

We obtained biopsy specimens from the frontal, vertex, temporoparietal, and occipital areas of the scalps of normal deceased subjects. All specimens were evaluated for the number of follicular units, hair counts, hair types, and stages of the hair cycle.

RESULTS

In total, 240 specimens were collected from 60 cadavers. Across all scalp sites, the temporoparietal area showed the lowest mean hair count, number of follicular units, terminal and vellus hairs, and terminal-to-vellus hair ratio. The average anagen-to-telogen hair ratio was comparable across all scalp sites. This study did not observe a significant association of hair parameters with gender differences or increasing age in all scalp areas.

CONCLUSIONS

The present study revealed the diversity of the hair index among different scalp areas and suggested that normal hair count values should be separately standardized on each scalp region. Our findings may provide useful reference values for the histopathological evaluation of hair disorders in Asians.

Histopathological Evidence of Occipital Involvement in Male Androgenetic Alopecia

Background: The occipital region of the scalp is generally accepted as an unaffected area of androgenetic alopecia (AGA) for both genders. However, evidence of AGA involving the occipital scalp has been demonstrated in women; meanwhile, it is unclear whether occipital involvement also occurs in men. Objective: We aimed to determine if there is occipital involvement in men with AGA. Methods: This case-control study compared hair counts of scalp biopsy specimens from the occipital region of 82 men with Hamilton-Norwood III-VII and 82 unaffected men. Results: The mean ages of men with AGA and controls were 40.1 ± 8.9 and 38.6 ± 10.5 years, respectively (P = 0.291). A significant decrease in total hair follicles, terminal hair follicles, follicular units and terminal to vellus (T:V) ratio, along with a significant increase in follicular stelae was indicated in the AGA group compared to controls (all P < 0.05). Subgroup analyses revealed that average counts of total hair follicles, terminal hair follicles and T:V ratios were also significantly lower in males with Hamilton-Norwood VI and VII than in controls (all P < 0.05). There were no correlations between increasing age and hair count parameters, but a significant negative association was found between total follicle numbers and disease duration (r = -0.23, P = 0.02). Conclusions: AGA can involve the occipital area of male patients with advanced disease. Therefore, the occiput of particular cases should not be used to determine reference data for normal scalp hair, and preoperative measurements of miniaturized hairs in the donor site are strongly recommended in all persons undergoing hair transplantation.

Effects of UV Induced-Photoaging on the Hair Follicle Cycle of C57BL6/J Mice

Purpose

To study the changes in the hair follicle cycle and related stem cells induced by photoaging to establish a mouse model of senescence in hair follicles.

Methods

There were 54 C57BL6/J mice randomly divided into three groups. The UVA group and the UVB group underwent photoaging induced by UV lamps for 8 weeks. Changes in skin and the hair follicle cycle were compared by physical signs, dermoscopy, and hematoxylin and eosin and Masson's staining in each group. Western blot, immunohistochemistry, and RT-qPCR were carried out to test canonical proteins and gene expression of the Wnt signaling pathway in the samples. Immunofluorescence was chosen to show variations in the stem cells related to the hair follicle cycle.

Results

There were more gray hairs in the UVA group than the other groups (P<0.05). Both diameter of the hair shaft and depth of hair root were significantly decreased in the UV groups (P<0.05). Stem cells and melanocytes of the hair follicles were reduced in the UVA group. UV, especially UVB, up-regulated the expression of the Wnt signaling pathway and prolonged anagen and telogen phases in the hair follicles, compared with the control group (P<0.05).

Conclusion

By decreasing the number of stem cells related to hair follicles, UVA induces hair follicle photoaging characterized by hair follicle miniaturization and gray hairs. UV up-regulated the expression of the Wnt signaling pathway, and the hair follicle cycle was significantly prolonged by UVB.

Female Pattern Hair Loss in Female and Male: A Quantitative Trichoscopic Analysis in Chinese Han Patients

Objectives: To investigate the trichoscopic features of female pattern hair loss (FPHL) in Chinese Han patients and analyze the difference between male and female patients with FPHL.

Materials and Methods: Trichoscopic images were taken in four different scalp areas, including right frontal hairline, vertex, right parietal and occipital areas. Hair density, hair shaft diameter, vellus hair ratio and single hair follicle unit ratio were counted manually and analyzed.

Results: Seventy-three subjects were enrolled in this study, including 38 patients with FPHL (28 females and 10 males) and 35 normal controls without hair loss. The hair density and hair shaft diameter of FPHL patients reduced in the whole scalp. Vellus hair ratio and single hair follicle unit ratio were both increased in FPHL compared to normal controls. The vertex was the most affected area and the hair shaft diameter showed the most significant difference. Parietal and occipital area were also affected in FPHL. The reduction or increase was correlated with the severity of Ludwig staging. Very few gender differences were detected in male and female FPHL patients.

Conclusion: FPHL patients showed decreased hair density and hair shaft diameter, accompanied by increased vellus hair ratio and single hair follicle unit ratio. Parietal and occipital area can be also affected in FPHL, though not as severe as in vertex area. FPHL in male basically has the same characteristic as those in female patients.

Limitation: The main limitation of the study is the small sample size which only enrolled 10 male FPHL patients, in comparison to the female cases. The findings could not be representative of the normal population with the limited sample size.

Evaluation of Hair Density and Hair Diameter in the Adult Thai Population Using Quantitative Trichoscopic Analysis

The data of hair density and hair diameter in the Asian population, especially in Thais, are limited. We aimed to evaluate hair density and hair diameter of members of the Thai population at different scalp sites and to determine the effect of sex and aging as well as to compare the results with those in groups of other ethnicities. Healthy Thais whose hair examination findings were normal were evaluated. Two hundred and thirty-nine subjects participated in this study, of whom 79 were male and 160 were female. Hair density and hair diameter were analyzed at four different scalp sites using quantitative trichoscopic analysis. The highest hair density in Thais was observed in the vertex area. Hair densities at four different scalp sites were significantly different from one another; only hair density at the vertex site showed no significant difference from that in the occipital area. In contrast, hair diameter did not show any statistically significant differences for the different sites. We observed decreased mean hair density with increasing age and found statistically significant differences between participants in their 20s and those in their 60s, while hair diameter remained consistent. Comparing our results with a previous study in other ethnicities, the hair densities in Asians are generally lower. In conclusion, hair density in the Thai population varies at different scalp sites. Aging is a factor in declining hair density. Asians have a lower hair density compared to Caucasian and African populations.

Significant relationship between temporal hair loss and other scalp areas in female pattern hair loss

Female pattern hair loss affects the central scalp, sparing the frontal hairline. The temporal area can also be affected by hair loss. We investigated the degree of temporal hair loss and correlation of other sites of scalp hair loss in Korean female pattern hair loss patients. A total of 109 women with female pattern hair loss were enrolled in this retrospective analysis. We measured hair density and thickness in five scalp sites including the frontal, vertex, occipital and bilateral temporal areas by phototrichogram. Frontal and vertex area hair loss were classified according to the Basic and Specific (BASP) classification, and temporal scalp and occiput areas were also assessed. Eighty-nine patients showed temporal hair loss. The mean of the hair density was lowest in the temporal area among all scalp areas. Total and thick hair densities of the frontal scalp were correlated with those of the vertex, temporal scalp and occiput in descending order, and hair thickness of the frontal scalp was more related with that of the temporal scalp than the vertex. In this study, temporal involvement is evident in female pattern hair loss. We suggest that temporal involvement should be added to pattern hair loss classification, especially BASP classification.