Light microscopy of the hair: a simple tool to "untangle" hair disorders

Trichoscopic Features of Syphilitic Alopecia and Alopecia Areata: A Comparative Study

Background

Syphilitic alopecia (SA) and alopecia areata (AA) are two distinct conditions that frequently present diagnostic difficulties, especially when differentiating between them due to their similar clinical presentations. Trichoscopy may help in differential diagnosis, but a comparison between trichoscopic features of SA and AA is yet to be researched.

Objective

To compare trichoscopic features between SA and AA and determine their discriminative values.

Methods

Electronic medical records and trichoscopic images of patients diagnosed with SA or AA between January 2000 and February 2022 were retrieved. Trichoscopic features were statistically compared, and their discriminative values were demonstrated as sensitivity, specificity, predictive value, likelihood ratio, and area under the receiver operating characteristic curve (AUC).

Results

A total of 69 patients were included: 23 SA and 46 AA cases were matched with a 1:2 ratio. Black dots, broken hairs, pigtail hairs, exclamation mark hairs, tapered hairs, angulated hairs, and non-pigmented regrowing hairs were significantly more prevalent in AA than in SA (all P<0.05), whereas erythematous background was more prevalent in SA than in AA patients (P=0.008). Among the aforementioned trichoscopic features, exclamation mark hairs and non-pigmented regrowing hairs had a high positive likelihood ratio for AA (16.17 and 8.34, respectively); however, only exclamation mark hairs revealed high AUC (AUC=0.816).

Conclusion

Despite the presence of several similar trichoscopic features between SA and AA, trichoscopy can aid in distinguishing between the two diseases. Exclamation mark hairs are the only trichoscopic feature that can be used to differentiate patients with clinically suspicious SA from those with AA.

Griscelli Syndrome in Skin of Color: A Trichoscopic Perspective

Introduction

Griscelli syndrome (GS) is a very rare autosomal recessive disorder, belongs to group of "silvery hair syndromes" which includes Chediak-Higashi syndrome (CHS) and Elejalde syndrome. Hair light microscopy helps in the differentiation of GS and CHS, as both manifest with clinical features. Trichoscopy is useful in the diagnosis of many hair shaft disorders. Here, authors describe the trichoscopic features of GS in skin of color.

Materials and Methods

This was an observational study conducted in a private dermatology clinic and in a tertiary care hospital. A total of 5 cases of suspected GS were referred by pediatrician. Consent was obtained. The demographic data in terms of age, gender, consanguinity, and clinical history was documented. Trichoscopic examination was performed with FotoFinder videodermoscope with 20× magnification, the clinical images were captured with Medicam 1000. Trichoscopy showed large and irregular pigment clumps in 4 cases. One case demonstrated hypopigmentation of hair without pigment clumps [Figure 3a].

Results

Trichoscopy showed large and irregular pigment clumps in 4 cases. One case demonstrated hypopigmentation of hair without pigment clumps.

Conclusion

Trichoscopy shows characteristic features GS. It is a useful method when facility for light or polarized microscope is unavailable.

Usefulness of Trichoscopy over Hair Light Microscopy in Menkes Disease

Menkes disease (MD) is a rare X-linked recessive neurodegenerative disorder caused by mutations in the ATP7A gene, with a high mortality rate within the first 3 years of life. It typically affects males and is characterized by impaired copper distribution and malfunction of several copper-dependent enzymes. Patients develop progressive muscle hypotonia associated with neurological damage and hair shaft dysplasia - particularly pili torti. Pili torti is usually very subtle in the first 3 months of life and gradually increases during the first year. Light microscopy examination in search for pili torti requires the observation of more than 50 hair shafts. In contrast, trichoscopy with a hand-held dermatoscope allows to easily identify the hair shaft defect. We report a case of a Hispanic male infant with MD in whom we show that trichoscopy is superior to hair light microscopy in revealing pili torti.

Critical thinking and diagnostic reasoning when advanced practitioners assess and treat skin conditions

Advanced clinical practitioner (ACP) roles require a broad range of knowledge of both medical and surgical medicine and the ability to work autonomously in a variety of settings. Despite around half of the UK adult population presenting with a skin condition requiring attention, this is something many ACPs feel unprepared to be consulted on. However, due to the complexity and large number of potential diagnoses, it is imperative that ACPs develop their confidence and knowledge to diagnosis, request investigations and initiate treatment for a patient with a skin complaint. In the first part of this clinical review the authors presented the key elements of history taking, consultation and assessment of the skin. This second clinical review discusses the main differential diagnoses, mimics, common investigations and treatments. This article is designed to support novice ACPs from acute hospital settings to primary care to develop a foundation of understanding in the main diagnosis and treatment options that should be considered following a clinical assessment of patients' skin outside the dermatology setting.

Hair microscopy: an easy adjunct to diagnosis of systemic diseases in children

Hair, having distinct stages of growth, is a dynamic component of the integumentary system. Nonetheless, derangement in its structure and growth pattern often provides vital clues for the diagnosis of systemic diseases. Assessment of the hair structure by various microscopy techniques is, hence, a valuable tool for the diagnosis of several systemic and cutaneous disorders. Systemic illnesses like Comel-Netherton syndrome, Griscelli syndrome, Chediak Higashi syndrome, and Menkes disease display pathognomonic findings on hair microscopy which, consequently, provide crucial evidence for disease diagnosis. With minimal training, light microscopy of the hair can easily be performed even by clinicians and other health care providers which can, thus, serve as a useful tool for disease diagnosis at the patient's bedside. This is especially true for resource-constrained settings where access and availability of advanced investigations (like molecular diagnostics) is a major constraint. Despite its immense clinical utility and non-invasive nature, hair microscopy seems to be an underutilized diagnostic modality. Lack of awareness regarding the important findings on hair microscopy may be one of the crucial reasons for its underutilization. Herein, we, therefore, present a comprehensive overview of the available methods for hair microscopy and the pertinent findings that can be observed in various diseases.

Microscopical discrimination of human head hairs sharing a mitochondrial haplogroup

In forensic analyses, determining the level of consensus among examiners for hair comparison conclusions and ancestry identifications is important for assessing the scientific validity of microscopical hair examinations. Here, we present data from an interlaboratory study on the accuracy of microscopical hair comparisons among a subset of experienced hair examiners currently analyzing hair in forensic laboratories across the United States. We examined how well microscopical analysis of hair can reliably be used to differentiate hair samples, many of which were macroscopically similar. Using cut hair samples, many sharing similar macroscopic and microscopic features, collected from individuals who share the same mitochondrial haplogroup as an indication of genetic relatedness, we tested multiple aspects that could impact hair comparisons. This research tested the extent to which morphological features related to ancestry and hair length influence conclusions. Microscopical hair examinations yielded accurate assessments of inclusion/exclusion relative to the reference samples among 85% of the pairwise comparisons. We found shorter hairs had reduced levels of accuracy and hairs from populations examiners were not familiar with may have impacted their ability to resolve features. The reliability of ancestry determinations is not yet clear, but we found indications that the existing categories are only somewhat related to current ethnic and genetic variation. Our results provide support for the continued utility of microscopical comparison of hairs within forensic laboratories and to advocate for a combined analytical approach using both microscopical analysis and mtDNA data on all forensic analyses of hair.