The assessment of nailfold capillaries: comparison of dermoscopy and nailfold videocapillaroscopy

Nail involvement in connective tissue diseases: an epidemiological, clinical, and dermoscopic study

BACKGROUND

The assessment of nail changes in connective tissue diseases (CTD) has been rarely explored in previous studies. The use of dermoscopy to study vascular changes in nailfolds is an interesting diagnostic technique. The aim of the study was to describe the epidemiological, clinical, and dermoscopic features of nail lesions in CTD.

METHODS

A prospective study was performed at the Dermatology Department of Habib Thameur Hospital (Tunis, Tunisia) in collaboration with the Internal Medicine Department over a period of 15 months, from July 2020 to September 2021, including patients diagnosed with systemic sclerosis (SS), systemic lupus erythematosus (SLE) and dermatomyositis (DM).

RESULTS

Our study included 48 patients. Nail involvement was found in 44 cases. Dermoscopic nailfold abnormalities were identified in 37 cases. The most common clinical features were ragged cuticle, nailfold erythema, and onycholysis. Additionally, splinter hemorrhage, longitudinal ridging, lunula abnormalities, melanonychia, trachyonychia, leukonychia, increase in transverse curvature, parrot beak nail, half and half nails, and onychorrhexis were described. Nailfold dermoscopy showed a normal pattern in 10 cases, a nonspecific pattern in nine cases (SLE), and a scleroderma pattern in 29 cases (SS and DM). The scleroderma pattern was further categorized into an early pattern (6), an active pattern (14), and a late pattern (9). Normal pattern was observed solely in patients in remission. The late scleroderma pattern was associated with disease duration and systemic involvement. In SLE, disease activity correlated with onycholysis, nailfold erythema, and pathologic pattern in dermoscopy. However, patients with DM displayed a positive correlation between pulmonary involvement and scleroderma pattern.

CONCLUSION

Nail involvement in CTD includes a diverse range of abnormalities. Despite being nonspecific, it can provide crucial clues for establishing a diagnosis. Nailfold dermoscopy serves as a mirror for microangiopathy, enabling the detection of changes at an initial stage, and thus, it becomes a diagnostic and prognostic tool.

Mikrozirkulationsstörungen der Haut: Microcirculation disorders of the skin

Veränderungen in der Mikrozirkulation der Haut sind ein häufig beobachtetes Begleitphänomen vieler Erkrankungen, weit über das Spektrum dermatologischer Krankheiten hinausreichend. Nicht alle dieser Veränderungen haben einen Krankheitswert, viele treten temporär auf, ohne schwerwiegende Folgen zu verursachen. Dies trifft für viele inflammatorische Erkrankungen wie die Psoriasis vulgaris oder das atopische Ekzem zu.

Daneben gibt es aber auch Erkrankungen, bei denen funktionell und morphologisch erkennbare Mikroangiopathien zu schwerwiegenden Krankheitsfolgen führen. Eine der wichtigsten Erkrankungen in diesem Zusammenhang ist die systemische Sklerose, eine autoimmune Systemerkrankung mit multiplen Organmanifestationen. Hier sind die Untersuchungen der kutanen Mikrozirkulation sowohl in der Erstdiagnose als auch in der Prognose‐ und Verlaufsbeurteilung von weitreichender Bedeutung.

Auch bei Erkrankungen der peripheren Hämodynamik wie der peripheren arteriellen Verschlusskrankheit (pAVK) und der chronisch venösen Insuffizienz (CVI) spielt das Verständnis von Mikrozirkulationsstörungen eine wichtige Rolle für die Therapie und die Erfolgskontrolle therapeutischer Interventionen.

Microcirculation disorders of the skin

Changes in the microcirculation of the skin are a frequently observed accompanying phenomenon of many diseases, far beyond the spectrum of dermatological diseases. Not all of these changes are pathological, many are transient and have no serious consequences. This is true for many inflammatory diseases such as psoriasis vulgaris or atopic eczema. However, there are also diseases in which functionally and morphologically recognizable microangiopathies lead to severe disease consequences. One of the most important diseases in this context is systemic sclerosis, an autoimmune systemic disease with multiple organ manifestations. Investigations of the cutaneous microcirculation are of great importance for the initial diagnosis as well as for prognosis and assessment of disease progression. In peripheral hemodynamic disorders such as peripheral arterial disease (PAD) and chronic venous insufficiency (CVI), understanding microcirculatory disturbances also plays an important role in therapy and in monitoring the success of therapeutic interventions.

Nailfold dermoscopy predicts the absence of a capillaroscopy sclerodermic pattern: The multicentre, prospective VASCUL-R trial

BACKGROUND

Nailfold capillaroscopy is recommended to diagnose primary or secondary Raynaud's phenomenon (RP). Capillaroscopy is normal in primary RP, which is the most frequent. Screening for RP capillary anomalies with nailfold dermoscopy has been promising.

OBJECTIVE

To determine whether normal nailfold dermoscopy-based on the absence of five criteria that define a sclerodermic pattern-is able to predict normal capillaroscopy with good positive-predictive value (PPV).

METHODS

Prospective, 2-phase (monocentre and multicentre) study on patients at first consultation for RP undergoing nailfold video capillaroscopy (NVC) and nailfold dermoscopy by two different 'blinded' trained observers, respectively, a vascular specialist and a dermatologist, not familiar with capillaroscopy. The five criteria noted were as follows: disorganization, megacapillaries, low capillary density, avascular areas and haemorrhages.

RESULTS

Based on 105 patients, the dermoscopy PPV for a normal NVC was 100% (p = 0.015), with 37.9% sensitivity, when no criterion was observed. Excluding haemorrhages, the PPV remained 100% (p < 0.0001), with sensitivity rising to 73.7% and 100% specificity.

CONCLUSION

Normal nailfold dermoscopy with the absence of four easy-to-observe criteria predicts normal NVC with an excellent PPV.

Methods of Assessing Nailfold Capillaroscopy Compared to Video Capillaroscopy in Patients with Systemic Sclerosis-A Critical Review of the Literature

INTRODUCTION

Nailfolds of patients with systemic sclerosis (SSc) provide an opportunity to directly visualize microvascular remodeling in SSc. Nailfold video capillaroscopy (NVC) remains the gold standard for assessing nailfold capillaroscopy (NFC). However, access to NVC is limited by expense and expertise. This review aims to synthesize current research on other NFC devices compared to NVC.

METHODS

The literature search included the primary research of adult patients with SSc as defined by the 2013 ACR/EULAR criteria. Methods of assessing NFC included stereomicroscopy/wide-field microscopy, ophthalmoscopy, dermatoscopy, smartphone devices, and digital USB microscopy. Primary outcomes included both qualitative (normal vs. abnormal nailfolds, overall pattern recognition, presence/absence of giant capillaries, hemorrhages, and abnormal morphology) and quantitative (capillary density and dimension) measures.

RESULTS

The search yielded 471 studies, of which 9 were included. Five studies compared NVC to dermatoscopy, two compared it to widefield/stereomicroscopy, one to smartphone attachments, and one to USB microscopy. In dermatoscopy studies, NVC had a higher percentage of images that were interpretable (63-77% vs. 100%), classifiable (70% vs. 84%), or gradable (70% vs. 79.3%) across three studies. Dermatoscopy had a lower sensitivity (60.2% vs. 81.6%) and higher specificity (92.5% vs. 84.6%) compared to NVC. One stereomicroscopy study found a significant difference between methods in capillary density in limited cutaneous SSc, while another found correlations in all parameters between stereomicroscopy and NVC. One smartphone lens had good agreement with NVC on abnormal capillary morphology and density. USB microscopy was able to differentiate between SSc and healthy controls using mean capillary width but not by capillary density.

DISCUSSION

A dermatoscope may serve as a more portable and affordable screening tool to identify a normal "scleroderma pattern", and images that need further corroboration by NVC. NFC parameters reported are heterogenous and the standardization of these parameters is important, especially in non-gold-standard devices.

Nailfold capillaroscopy

Nailfold capillaroscopy is a safe and well-established method for the assessment of structural alterations of the microcirculation. It is a crucial tool in the investigation and monitoring of patients presenting with Raynaud's phenomenon. Detection of the characteristic "scleroderma pattern" on capillaroscopy may indicate an underlying rheumatic disease, particularly systemic sclerosis (SSc). Herein, we highlight the practical aspects of videocapillaroscopy, including image acquisition and analysis, with mention of dermoscopy. Special emphasis is placed on standardized use of terminology to describe capillary characteristics. Systematic evaluation of images in discerning the normal from the abnormal using the validated European Alliance of Associations for Rheumatology (EULAR) Study Group consensus reporting framework is paramount. In addition to the relevance of capillaroscopy in the (very) early diagnosis of SSc, its emerging predictive value (especially capillary loss) for new organ involvement and disease progression is underscored. We further provide capillaroscopic findings in selected other rheumatic diseases.

Role of short courses on nailfold capillaroscopy in obtaining abilities for the identification of microvasculopathy in patients with Raynaud's phenomenon

INTRODUCTION

An early distinction between "normal" and "abnormal" capillaroscopic pattern during the first visit to a dermatologist has a crucial significance for a diagnostic management of Raynaud's phenomenon (RP). There exists a question about the level of expertise sufficient to evaluate the microcirculation.

AIM

To evaluate the utility of short courses on NFC among dermatologists and medical students in obtaining sufficient abilities for the identification of microvasculopathy in patients with RP using videocapillaroscope and handheld dermoscope.

METHODS

Both groups participated in 1-h course on NFC. Before the course, participants were asked to classify 20 videocapillaroscopic and 10 dermoscopic capillaroscopic pictures into "normal" or "abnormal" pattern. Each picture was displayed on a separate slide MS PowerPoint for 10 s. The evaluation was repeated soon after the course.

RESULTS

A total of 36 dermatologists and 49 medical students were enrolled. The rate of properly classified dermoscopic and videodermoscopic pictures increased after the course in both groups, but students improved the accuracy of classification on dermoscopic pictures to the greater extent than dermatologists. The rate of correctly recognized pictures with "abnormal" pattern was significantly greater than ones with "normal" pattern at the baseline and after the course, independently of imagining tool.

CONCLUSIONS

Short courses on NFC may improve the classification of capillaroscopic images, even in medical staff with no previous experience in NFC. The recognition of capillaroscopic abnormalities seems to be easier than obtaining the confidence that evaluated picture has "normal pattern."

Nailfold capillaroscopy: a survey of current UK practice and 'next steps' to increase uptake among rheumatologists

OBJECTIVES

To identify barriers to the use of nailfold capillaroscopy as a diagnostic tool for patients presenting with Raynaud's phenomenon in UK rheumatology centres and to obtain rheumatologists' views on a proposed internet-based standardized system for clinical reporting of nailfold capillaroscopy images.

METHODS

An online survey was developed using expert opinion from clinicians, scientists and health service researchers. The survey was piloted and sent to UK-based rheumatologists using established electronic mailing lists between October 2020 and March 2021. Survey data were analysed using descriptive statistics.

RESULTS

A total of 104 rheumatologists representing rheumatology centres across the UK responded to the survey. Wide variations in terms of workloads and practices were described. Thirty-four (33%) respondents reported using nailfold capillaroscopy only at their own centre, 33 (32%) referred to other centres, 9 (9%) did both and 28 (27%) did not use capillaroscopy at all. Of the 43 respondents using capillaroscopy on site, 25 (58%) used either a dermatoscope or universal serial bus microscope and 9 (21%) used videocapillaroscopy. Among the 61 respondents not undertaking capillaroscopy on site, barriers included lack of equipment (85%), lack of experience in acquiring images (69%) and lack of expertise in interpreting images (67%). Sixty-six respondents (63%) expressed interest in an internet-based, standardized automated system for reporting images.

CONCLUSION

Most UK rheumatologists currently do not perform nailfold capillaroscopy on site. An internet-based nailfold capillaroscopy system for use with low-cost microscopes as well as with videocapillaroscopy could help increase uptake of capillaroscopy and thereby facilitate early diagnosis of SSc across the UK.

Detection of microvascular changes in systemic sclerosis and other rheumatic diseases

Morphological and functional analysis of the microcirculation are objective outcome measures that are recommended for use in the presence of clinical signs of altered peripheral blood flow (such as Raynaud phenomenon), which can occur in systemic sclerosis (SSc) and other autoimmune rheumatic diseases. Several advanced non-invasive tools are available for monitoring the microcirculation, including nailfold videocapillaroscopy, which is the best-studied and most commonly used method for distinguishing and quantifying microvascular morphological alterations in SSc. Nailfold videocapillaroscopy can also be used alongside laser Doppler techniques to assist in the early diagnosis and follow-up of patients with dermatomyositis or mixed connective tissue disease. Power Doppler ultrasonography, which has been used for many years to evaluate the vascularity of synovial tissue in rheumatoid arthritis, is another promising tool for the analysis of skin and nailbed capillary perfusion in other autoimmune rheumatic diseases. Other emerging methods include raster-scanning optoacoustic mesoscopy, which offers non-invasive high-resolution 3D visualization of capillaries and has been tested in psoriatic arthritis and SSc. The principle functions and operative characteristics of several non-invasive tools for analysing microvascular changes are outlined in this Review, and the clinical roles of validated or tested imaging methods are discussed for autoimmune rheumatic diseases.

Comparison between low cost USB nailfold capillaroscopy and videocapillaroscopy: a pilot study

OBJECTIVES

Universal serial bus (USB) microscopy (capillaroscopy) could provide all rheumatologists with an easy-to-use, low-cost tool to examine the nailfold capillaries to facilitate early diagnosis of SSc. The objectives of this pilot study were to examine the feasibility of acquiring and analysing images using USB microscopy and to compare results to videocapillaroscopy.

METHODS

Videocapillaroscopy and USB microscope images were obtained from the right and left ring fingers of 20 patients with SSc and 20 healthy control subjects. In addition to generating panoramic capillary mosaics from across the whole nailbed, custom software made fully automated measurements of vessel structure including capillary width and density. The area under the receiver operating characteristic curve (AZ) was used to measure separation between the SSc and healthy control groups.

RESULTS

High quality images could be generated from the USB microscope, with reconstructed USB images comparing very favourably with those obtained using videocapillaroscopy. Using USB microscope images, the receiver operating characteristic curve AZ for group separation based on mean width was 0.81 (standard error 0.120) compared with 0.81 (standard error 0.095) for the (gold standard) videocapillaroscopy. The receiver operating characteristic curve AZ for group separation using capillary density was 0.48 (standard error 0.16) for USB microscope images, compared with 0.70 (standard error 0.10) for videocapillaroscopy.

CONCLUSION

In this pilot study, USB capillaroscopy was able to discriminate between patients with SSc and controls as well as videocapillaroscopy on the basis of capillary width. This finding, together with the high-quality images obtained, highlights the potential of USB capillaroscopy as a low-cost, easily accessible clinical and research tool.

Quantitative nailfold capillaroscopy-update and possible next steps

We review the exciting potential (and challenges) of quantitative nailfold capillaroscopy, focusing on its role in systemic sclerosis. Quantifying abnormality, including automated analysis of nailfold images, overcomes the subjectivity of qualitative/descriptive image interpretation. First we consider the rationale for quantitative analysis, including the potential for precise discrimination between normal and abnormal capillaries and for reliable measurement of disease progression and treatment response. We discuss nailfold image acquisition and interpretation, and describe how early work on semi-quantitative and quantitative analysis paved the way for semi-automated and automated analysis. Measurement of red blood cell velocity is described briefly. Finally we give a personal view on 'next steps'. From a clinical perspective, increased uptake of nailfold capillaroscopy by general rheumatologists could be achieved via low-cost hand-held devices with cloud-based automated analysis. From a research perspective, automated analysis could facilitate large-scale prospective studies using capillaroscopic parameters as possible biomarkers of systemic sclerosis-spectrum disorders.

Handheld dermatoscopy as an easy-to-use capillaroscopic instrument in rheumatoid arthritis: a cross-sectional study

Background/aim

Nailfold video capillaroscopy is considered as a reliable method for evaluating peripheral microangiopathy in rheumatologic diseases. In this study, we aimed to demonstrate the utility of handheld dermatoscopy as an easy-to-use nailfold capillaroscopic instrument in patients with rheumatoid arthritis.

Materials and methods

This cross-sectional study included patients with rheumatoid arthritis and healthy subjects. A handheld dermatoscopic examination of proximal nail fold was performed in each subject. The possible correlation of capillaroscopic findings with disease activity was evaluated using the disease activity score 28 (DAS28).

Results

A total of 59 patients with rheumatoid arthritis and 60 healthy subjects were enrolled in the study. The presence of capillaryenlargement, avascular areas, capillary deformities, and capillary vascular anomalies in the group of patients showed a statistically significant difference when compared with the healthy subjects. No correlation was found between the nail fold capillaroscopic findings and DAS28 score.

Conclusion

Hand-held dermatoscopy seems to be a useful technique in the evaluation of nail fold capillary changes. We suggest that in patients with rheumatoid arthritis, when capillaroscopic examination is needed, it can be evaluated using handheld dermatoscopy. Selected patients who showed findings using this method can be further examined with classical capillaroscopy to obtain more quantitative data.

New perspectives in the imaging of Raynaud's phenomenon

The last 10-20 years have seen huge strides in imaging science. The aim of this review article is to share with the reader the key recent advances in non-invasive imaging of the digital (finger) vasculature in patients with Raynaud's phenomenon (RP), including in systemic sclerosis (SSc)-related digital vasculopathy. For the rheumatologist, seeing a patient with RP is an opportunity for early diagnosis of an underlying SSc-spectrum disorder or (conversely) for reassuring the patient with primary (idiopathic) RP. Non-invasive imaging techniques can help to provide diagnostic certainty. In addition, they can provide new insights into pathophysiology and have the potential to facilitate the development of much needed effective treatments by providing primary and secondary endpoints for randomized controlled trials: validation studies are ongoing. This review article focuses on nailfold capillaroscopy, thermography, and laser Doppler methods but also discusses (briefly) other technologies, including optical coherence tomography, multispectral imaging, and photoacoustic imaging. Key recent advances are the increasing use/availability of nailfold capillaroscopy (and better understanding of the role of low-cost hand-held devices), increased accessibility of thermography (including mobile phone thermography), and increased application of laser Doppler methods to the study of RP/digital vasculopathy (in particular of laser Doppler imaging and laser speckle contrast imaging, both of which measure blood flow over an area rather than at a single site). In an era of precision medicine, non-invasive imaging techniques can help stratify risk of (a) SSc in the patient with RP and (b) digital vascular disease progression in the patient with an SSc-spectrum disorder.

Raynaud's phenomenon

Raynaud's phenomenon (RP) is common, affecting approximately 5% of the population, and is important to the rheumatologist because it is often the presenting symptom of connective tissue disease, especially of systemic sclerosis (SSc)-spectrum disorders. RP therefore provides a window of opportunity for early diagnosis. When RP is associated with SSc it is particularly challenging to treat. This review begins with a discussion of some of the recent advances in our understanding of the pathogenesis of RP: it is through increased understanding of the complex pathophysiology of RP that we are most likely to develop new therapies. The following questions are then addressed (with three clinical scenarios demonstrating key principles of assessment and management): 1. How can we predict underlying connective tissue disease in the patient presenting with Raynaud's? 2. How can we measure severity of Raynaud's? 3. What are the latest advances in treatment of connective tissue disease-related digital vasculopathy?

Impact and associates of digital pitting in patients with systemic sclerosis: a pilot study

Objective: Despite being a cardinal clinical sign of systemic sclerosis (SSc), digital pitting has been little studied. Our objective was to test, in a pilot study, the hypothesis that pitting is painful and associated with digital vascular disease severity.Method: Fifty patients with SSc were recruited: 25 with and 25 without digital pitting. Fingertip pain was assessed on a 0-10 scale. Thermography of both hands assessed surface temperature, allowing calculation of the distal-dorsal difference (temperature gradient) for each finger. Nailfold capillaroscopy was performed in each finger using a dermatoscope, and graded on a 0-3 scale (0 = normal; 3 = grossly abnormal).Results: In the 25 patients with digital pitting, 65 fingers in total were affected (mainly the index and middle fingers). Pain scores were higher in 'pitting' patients [median 4 (interquartile range 3-8) vs 0 (0-2), p < 0.001], and pitting patients reported that pitting impacted on activities of everyday living. Temperature gradients along the fingers did not differ significantly between patients with and without pitting (p = 0.248). Pitting patients were more likely to have 'grossly abnormal' capillaries than those without pitting, and less likely to have 'no/mild' nailfold capillary changes.Conclusions: Digital pitting is painful and impacts on hand function. Capillaroscopy findings provide further support for an association between pitting and severity of digital vascular change. Larger, more comprehensive studies are required to examine the pathophysiology of pitting and to pave the way to therapeutic intervention, ideally including preventive strategies.

Practical issues in assessing nailfold capillaroscopic images: a summary

Nailfold capillaroscopy (NC) is a highly sensitive, safe, and non-invasive technique to assess involvement rate of microvascularity in dermatomyositis and systemic sclerosis. A large number of studies have focused on NC pattern description, classification, and scoring system validation, but minimal information has been published on the accuracy and precision of the measurement. The objective of this review article is to identify different factors affecting the reliability and validity of the assessment in NC. Several factors can affect the reliability of the examination, e.g., physiological artifacts, the nailfold imaging instrument, human factors, and the assessment rules and standards. It is impossible to avoid all artifacts, e.g., skin transparency, physically injured fingers, and skin pigmentation. However, minimization of the impact of some of these artifacts by considering some protocols before the examination and by using specialized tools, training, guidelines, and software can help to reduce errors in the measurement and assessment of NC images. Establishing guidelines and instructions for automatic characterization and measurement based on machine learning techniques also may reduce ambiguities and the assessment time.

Raynaud's phenomenon

Raynaud's phenomenon can be either primary (idiopathic) or secondary to underlying disease including systemic sclerosis. Primary Raynaud's phenomenon is very common, affecting approximately 3%-5% of the general population. Although much rarer, systemic sclerosis-related Raynaud's phenomenon can be particularly severe, progressing to digital ulceration in approximately 50% of patients. Raynaud's phenomenon can have a major impact on quality of life. This review has a focus on the systemic sclerosis-related Raynaud's phenomenon (which is the most researched form of Raynaud's phenomenon and probably the most challenging to treat) and on recent advances. Epidemiology (including transition from 'isolated' to systemic sclerosis-related Raynaud's phenomenon), pathogenesis, diagnosis and assessment are discussed, followed by the treatment of both 'uncomplicated' and 'complicated' Raynaud's phenomena (i.e. Raynaud's phenomenon which has progressed to digital ulceration and/or critical ischaemia). Finally, some of the major challenges for the next 5-10 years are highlighted.