Trichoscopy - a valuable tool for identifying conditions mimicking androgenetic alopecia.

Androgenetic alopecia (AGA) is the most prevalent type of hair loss in women and men. Recently, a European consensus group published guidelines for the diagnostic evaluation of AGA in men, women, and adolescents. This S1 guideline presents expert opinion-based recommendations for gender-dependent steps in the diagnostic procedure, which can easily be implemented in the daily clinical routine. For diagnosing AGA, detailed anamnesis and objective learning are not enough because there are several conditions mimicking this disease. Trichoscopy can be considered an important, non-invasive tool for diagnosing hair and scalp disorders that may have similar clinical signs to AGA.

Transmission infrared micro-spectroscopic study of individual human hair.

Significance: Understanding the optical transmission property of human hair, especially in the infrared regime, is vital in physical, clinical, and biomedical research. However, the majority of infrared spectroscopy on human hair is performed in the reflection mode, which only probes the absorptance of the surface layer. Aim: The direct transmission spectrum of individual hair without horizontal cut offers a rapid and non-destructive test of the hair cortex but is less investigated experimentally due to the small size and strong absorption of the hair. Approach: In this work, we conduct a transmission infrared micro-spectroscopic study on individual human hair with the help of Fourier-transform infrared microscope experimentally. Its high spatial resolution of infrared micro-spectroscopy further allows the comparison among different regions of hair. The geometry effect of the internal hair structure is also quantified using the finite-element simulation, which supports the experimental results. Results: By utilizing direct measurements of the transmission spectrum using a Fourier-transform infrared microscope, the human hair is found to display prominent band filtering behavior. In a case study of adult-onset Still's disease, the corresponding infrared transmission exhibits systematic variations of spectral weight as the disease evolves. Conclusions: Our work implies that the variation of spectral weight may relate to the disordered microscopic structure variation of the hair cortex during an inflammatory attack. Our work reveals the potential of hair infrared transmission spectrum in tracing the variation of hair cortex retrospectively.

Invention of automated numerical algorithm adopting binarization for the evaluation of scalp hair coverage: An image analysis providing a substitute for phototrichogram and global photography assessment for hair diseases.

BACKGROUND: The efficacy of therapeutic modalities for hair disease can be evaluated globally by photo assessment and more precisely by phototrichogram (PTG). However, the latter procedure is laborious, time consuming, subject to inter-observer variation, and requires hair clipping. OBJECTIVE: To establish an automated and patient/investigator friendly methodology enabling quantitative hair amount evaluation for daily clinical practice. METHODS: A novel automated numerical algorithm (aNA) adopting digital image binarization (i.e., black and white color conversion) was invented to evaluate hair coverage and measure PTG parameters in scalp images. Step-by-step improvement of aNA was attempted through comparative analyses of the data obtained respectively by the novel approach and conventional PTG/global photography assessment (GPA). RESULTS: For measuring scalp hair coverage, the initial version of aNA generally agreed with the cumulative hair diameter as assessed using PTG, showing a coefficient of 0.60. However, these outcomes were influenced by the angle of hair near the parting line. By integrating an angle compensation formula, the standard deviation of aNA data decreased from 5.7% to 1.2%. Consequently, the coefficient of determination for hair coverage calculated using the modified aNA and cumulative hair diameter assessed by PTG increased to 0.90. Furthermore, the change in hair coverage as determined by the modified aNA protocol correlated well with changes in the GPA score of images obtained using clinical trials. CONCLUSION: The novel aNA method provides a valuable tool for enabling simple and accurate evaluation of hair growth and volume for clinical trials and for treatment of hair disease.

The dermatoscope in the hair clinic: Trichoscopy of scarring and nonscarring alopecia.

Trichoscopy is currently regarded as an essential part of the hair loss consultation. It allows visualization of morphologic structures that are not obvious to the naked eye, including peri- and interfollicular skin surface abnormalities and changes to hair shaft thickness and shape. In this paper, we aim to discuss current knowledge on trichoscopy of the most common forms of scarring and nonscarring alopecias.

MRI safety for leave-on powdered hair thickeners under 1.5-T and 3.0-T MRI: measurement of deflection force, MRI artifact, and evaluation of preexamination screening.

This study aimed to clarify the magnetic resonance imaging (MRI) compatibility of leave-on powdered hair thickeners by evaluating the displacement force and image artifacts of commercially available leave-on powdered hair thickeners on MRI devices and their response to metal and ferromagnetic detectors. Thirteen types of leave-on powdered hair thickeners were studied: nine hair thickener and four foundation types. MRI systems of 1.5 T and 3.0 T were used. Deflection angles and MR image artifacts according to ASTM F2052 and F2119 were evaluated. Handheld metal and ferromagnetic detectors were used to investigate whether hair thickeners could be detected in screening before MRI examinations. The hair thickener type had a deflection angle of 0°, whereas the foundation type had a deflection angle of 90°, indicating a strong physical effect. Significant image artifacts appeared only on the foundation type. The foundation type reacted at distances of less than 10 cm only with a ferromagnetic detector. Foundation-type leave-on powdered hair thickeners containing magnetic substances exhibited strong physical effects and produced significant image artifacts, and those can only be detected by screening with a ferromagnetic detector.

SharpRazor: Automatic removal of hair and ruler marks from dermoscopy images.

BACKGROUND: The removal of hair and ruler marks is critical in handcrafted image analysis of dermoscopic skin lesions. No other dermoscopic artifacts cause more problems in segmentation and structure detection. PURPOSE: The aim of the work is to detect both white and black hair, artifacts and finally inpaint correctly the image. METHOD: We introduce a new algorithm: SharpRazor, to detect hair and ruler marks and remove them from the image. Our multiple-filter approach detects hairs of varying widths within varying backgrounds, while avoiding detection of vessels and bubbles. The proposed algorithm utilizes grayscale plane modification, hair enhancement, segmentation using tri-directional gradients, and multiple filters for hair of varying widths. We develop an alternate entropy-based processing adaptive thresholding method. White or light-colored hair, and ruler marks are detected separately and added to the final hair mask. A classifier removes noise objects. Finally, a new technique of inpainting is presented, and this is utilized to remove the detected object from the lesion image. RESULTS: The proposed algorithm is tested on two datasets, and compares with seven existing methods measuring accuracy, precision, recall, dice, and Jaccard scores. SharpRazor is shown to outperform existing methods. CONCLUSION: The Shaprazor techniques show the promise to reach the purpose of removing and inpaint both dark and white hair in a wide variety of lesions.

Hair Cortisone Predicts Lower Stress-induced Salivary Cortisol Response: Resting-state Functional Connectivity Between Salience and Limbic Networks.

Previous studies revealed that high long-term hypothalamic-pituitaryadrenal (HPA) axis activity measured by the hair cortisol concentrations predicts lower acute stress cortisol response and reported the influences of hair cortisol on brain activity during acute stress exposure. However, considering that long-term HPA axis activity has a close relationship with the brain's resting-state functional connectivity (RSFC), the current study aimed to explore the role of RSFC between limbic and salience network in this relationship. Seventy-seven healthy participants underwent resting-state imaging scans before performing the acute ScanSTRESS task. Saliva samples were collected to assess the levels of acute stress salivary cortisol. Hair samples were also collected, and the corticosteroid concentration extracted from these samples were used as a biomarker of long-term HPA axis activity. High hair cortisone (HairE) levels predicted lower acute stress cortisol response. Moreover, high HairE levels were significantly correlated with enhanced RSFC between limbic and salience networks, while RSFC was negatively associated with acute stress cortisol response. Importantly, the RSFC between left insula and left parahippocampus mediated the association between HairE and acute cortisol stress response. Taken together, this study uncovers the important role of RSFC between salience and limbic networks in the long-term relationship between HairE and acute cortisol response and contributes to a deeper understanding of the individual differences in acute stress response.

ChimeraNet: U-Net for Hair Detection in Dermoscopic Skin Lesion Images.

Hair and ruler mark structures in dermoscopic images are an obstacle preventing accurate image segmentation and detection of critical network features. Recognition and removal of hairs from images can be challenging, especially for hairs that are thin, overlapping, faded, or of similar color as skin or overlaid on a textured lesion. This paper proposes a novel deep learning (DL) technique to detect hair and ruler marks in skin lesion images. Our proposed ChimeraNet is an encoder-decoder architecture that employs pretrained EfficientNet in the encoder and squeeze-and-excitation residual (SERes) structures in the decoder. We applied this approach at multiple image sizes and evaluated it using the publicly available HAM10000 (ISIC2018 Task 3) skin lesion dataset. Our test results show that the largest image size (448 × 448) gave the highest accuracy of 98.23 and Jaccard index of 0.65 on the HAM10000 (ISIC 2018 Task 3) skin lesion dataset, exhibiting better performance than for two well-known deep learning approaches, U-Net and ResUNet-a. We found the Dice loss function to give the best results for all measures. Further evaluated on 25 additional test images, the technique yields state-of-the-art accuracy compared to 8 previously reported classical techniques. We conclude that the proposed ChimeraNet architecture may enable improved detection of fine image structures. Further application of DL techniques to detect dermoscopy structures is warranted.

Trichoscopic Diagnosis of Structural Hair Defects in a Clinical Setting: A Cross-Sectional Analytical Study.

BACKGROUND: Trichoscopy is a simple, noninvasive procedure practiced in the diagnosis of a multitude of scalp and hair disorders. Hair shaft abnormalities usually represent a diagnostic challenge to dermatologists. OBJECTIVES: The aim of the study was to determine the practicality, versatility, and value of using the handheld dermoscope in the assessment of hair shaft abnormalities and the diagnosis of different hair/scalp disorders. METHODS: Eight hundred and seven patients of both sexes, aged from 1 to 76 years, with complaints pertaining to scalp and hair, were the subjects of the study. All patients were examined by the handheld dermoscope, and 400 were additionally examined by the folliscope, digital dermoscope, or their hairs mounted for light microscopy. RESULTS: Based on trichoscopic findings, more than half the patients demonstrated thinned terminal hairs and a predominance of single-haired scalp pilosebaceous units (57% and 55.5%, respectively). Over a quarter of the patients showed hair diameter heterogeneity, upright regrowing hairs, and increased vellus hairs (37%, 31%, and 25%, respectively). Other trichoscopic findings included scalp scaling (19%), hair weathering (12%), thinned wavy hairs (10.5%), brush-like hair fractures (9%), exclamation mark hairs (9%), and longitudinal cleavage (trichoptilosis) (8%). The clinical diagnostic spectrum was topped by the following diagnoses in order of frequency: female pattern hair loss, telogen effluvium, traction alopecia, and trichotillomania. Trichodynia appeared to be significantly associated with numerous hair shaft abnormalities. CONCLUSION: Most hair shaft abnormalities can be reliably diagnosed with high accuracy using a handheld dermoscope in an office setting. Skillful knowledge of dermoscopy is an important aid in the diagnosis of hair and scalp disorders.

Transmission electron microscopy of pili annulati.

BACKGROUND: Little is known about the ultrastructure of pili annulati. OBJECTIVES: To examine with transmission electron microscopy affected hairs of a family, whose diagnosis had been confirmed in five individuals with scanning electron microscopy, which showed surface undulations with "curtain-like" folding of the hair cuticula and to compare the findings with normal control. METHODS: Hairs of two affected patients and one control were embedded in resin and cut lengthwise to produce ultra-thin sections. RESULTS: The normal hair showed a parallel arrangement of dark lines associated with less electron-dense wide bands. Small cavities could be observed, mostly in the dark lines, affected hairs had a large number of cavities, associated or not with the insertion of melanosomes and loss of parallelism of the dark lines. Higher magnification showed a significant loss of this parallelism, resembling "wood grooves". Widened dark lines were observed in some areas. STUDY LIMITATIONS: Only a few hairs were examined. CONCLUSIONS: The present results suggest that the microcanaliculi of the hair surface, easily found with scanning electron microscopy, may be secondary not only to the cavities seen in the sections but also to the disorder of proteins that form this region, demonstrated by the changes of the cortex dark lines.

A case of infantile tinea of vellus hair confirmed by dermoscopy and scanning electron microscopy and detection of infected source.

Tinea of vellus hair is an unusual form of superficial skin infection, with a distinct prognosis from ordinary tinea. We report a case of tinea of vellus hair in a 7-month-old infant. Infected hairs were observed by dermoscopy and scanning electron microscopy (SEM). Single nucleotide polymorphism (SNP) detection confirmed the pet cat as a source causing the infection. A literature review was performed to summarize the clinical characteristics of this form of infection.

Quantitative characterization of 3D structure of vellus hair arrector pili muscles by micro CT.

BACKGROUND: Vellus hair is the fine, wispy hair found over most of the body surface, and the arrector pili muscles (hair muscle) serve to raise these hairs. Hair muscles are also critical for skin regeneration, contributing to the maintenance of stem cells in epidermis and hair follicles. However, little is known about their fundamental properties, especially their structure, because of the limitations of conventional two-dimensional histological analysis. OBJECTIVES: We aimed to quantitatively characterize the structure of vellus hair muscles by establishing a method to visualize the 3D structure of hair muscle. METHODS: We observed young female abdominal skin specimens by means of X-ray micro CT and identified hair muscles in each cross-sectional CT image. We then digitally reconstructed the 3D structure of the hair muscles on computer (digital-3D skin), and numerically evaluated their structural parameters. RESULTS: Vellus hair muscles were clearly distinguished from the surrounding dermal layer in X-ray micro CT images and were digitally reconstructed in 3D from those images for quantification of the structural parameters. The mean value of number of divisions of vellus hair muscles was 1.6, mean depth was 943.6 µm from the skin surface, mean angle to the skin surface was 28.8 degrees, and mean length was 1657.9 µm. These values showed relatively little variation among subjects. The mean muscle volume was approximately 20 million µm3 but showed greater variability than the other parameters. CONCLUSION: Digital-3D skin technology is a powerful approach to understand the tiny but complex 3D structure of vellus hair muscles. The fundamental nature of vellus hair muscles was characterized in terms of their 3D structural parameters, including number of divisions, angle to the skin surface, depth, and volume.

Isolated hair loss on the eyebrow: five cases with trichoscopic features.

Alopecia areta (AA) and trichotillomania (TTM) are common causes for hair loss on the eyebrows. Yellow dots, vellus hairs, anisotrichosis, empty follicular openings, and black dots were observed in the present study's patients with AA. Split hairs, question mark hairs, broken hairs, flame hairs, black dots, hairs with different lengths, and hemorrhagic areas were found in the patients with TTM. Trichoscopy is a very useful and helpful technic in distinguishing AA and TTM on the eyebrows.

High-resolution imaging of the mouse-hair-cell hair bundle by scanning electron microscopy.

Scanning electron microscopy (SEM) allows cell surface imaging at a sub-nanometric resolution. However, the sample requires a specific preparation to sustain the high vacuum of the SEM and be electrically conductive. The sample preparation consists of dissection, fixation, dehydration, metal coating, and tissue mounting. Here we provide a comprehensive protocol to perform SEM on the mouse's inner ear, and image the hair bundles at high resolution. Hair bundles are the force-sensitive organelles located at the apical surface of hair cells. For complete details on the use and execution of this protocol, please refer to Trouillet et al. (2021).

Tufted hairs: A bouquet of flowers in different hair diseases.

Tufted hairs, an unusual hair follicle dysplasia, are characterized by several hair shafts grouped together, emerging from a single hair follicle-like "doll's hair". This clinical picture is considered characteristic of folliculitis decalvans (FD). However, the emergence of grouped hair shafts from a single follicle can also be observed in other hair disorders, even if not as a distinctive diagnostic sign. This paper aims to collect and analyze all clinical and trichoscopic features of different hair diseases with tufted hairs to find distinctive features, helping the clinician with the diagnosis.