Confocal histopathology of irritant contact dermatitis in vivo and the impact of skin color (black vs white)

Comparative evaluation of six commercial adult toothpaste formulations reveals cytotoxicity and altered functions in a human oral melanocyte model: an in vitro study

This study aims to compare six commercial adult toothpaste (labeled as A, B, C, D, E, and F) for cytotoxicity and melanocyte function alterations in vitro using primary human epidermal melanocytes from a Caucasian donor (HEMn-LP cells) as a model of oral melanocytes. Cells were incubated with toothpaste extracts (50% w/v) in culture media at dilutions (1:25, 1:50, 1:100, 1:200, 1:500, 1:800, and 1:1000) for 24 h. MTS and LDH assays were used to assess cytotoxicity. The effects of noncytotoxic toothpaste concentrations on melanocyte functional endpoints were then examined using spectrophotometric methods. All toothpaste showed concentration-dependent cytotoxicity that was heterogeneous across toothpaste containing SLS detergent. IC50 values of cytotoxicity followed the order: A = E > C > B > D > F. To compare toothpaste, they were tested at 1:800 and 1:1000 dilutions that were noncytotoxic after 24 h. None of the toothpaste affected cellular melanin production. However, toothpaste A, C, and D suppressed tyrosinase activity at both dilutions, while toothpaste B suppressed tyrosinase activity only at 1:800 dilution. Toothpaste A, C, E, and F elevated ROS production at 1:800 dilution, with no change at 1:1000 dilution. Toothpaste has a heterogeneous effect on melanocytes. Toothpaste B, E, and F at 1:1000 dilution were the safest as they did not alter melanocyte functions at this dilution, although toothpaste F is the least cytotoxic of these. Future studies are necessary to expand these results in a physiological environment of oral tissue. The findings of this study provide novel insight into the biocompatibility studies of toothpaste on oral melanocytes. They can aid dental practitioners and consumers in selecting noncytotoxic toothpaste that do not contribute to ROS generation by melanocytes in the oral cavity or lead to cytotoxicity and impaired cellular function.

Real-Time Reflectance Confocal Microscopy of Cutaneous Graft-versus-Host Disease Correlates with Histopathology

Reflectance confocal microscopy (RCM) allows noninvasive, real-time evaluation of the skin at a resolution akin to histopathology (HP), but its application in cutaneous graft-versus-host disease (GVHD) has not been extensively assessed. We describe RCM features of cutaneous GVHD including acute (aGVHD), late acute, chronic (cGVHD; sclerotic and nonsclerotic subtypes), and inactive GVHD and correlate RCM with same-site HP for a subset of patients. Thirty-two adult and pediatric allogeneic hematopoietic cell transplantation (allo-HCT) recipients with cutaneous GVHD received RCM imaging of ≥1 lesions (n = 44), 13 of which necessitated skin biopsy. RCM images were deidentified and assessed by 2 RCM experts blinded to clinical and HP findings to reach a consensus on the features and patterns of the inflammatory dermatoses. Major RCM features (present in ≥65% of lesional sites) and patterns were reported. To determine the correlation between RCM and HP, detection of cellular features and patterns of inflammatory dermatoses were compared using percent agreement and prevalence-adjusted, bias-adjusted kappa estimates. Seven patients with early or late aGVHD (7 lesions) had irregular honeycombing, spongiosis, dermoepidermal junction (DEJ) and dermal inflammation, and melanophages; those with early aGVHD also had hyperkeratosis, dilated vessels, and coarse connective tissue. Both groups had an interface dermatitis pattern. Eighteen patients with nonsclerotic cGVHD (24 lesions) had irregular honeycombing, spongiosis, DEJ and dermal inflammation, dilated vessels, coarse connective tissue, and interface and spongiotic dermatitis patterns. Three sclerotic patients with cGVHD (7 lesions) had irregular honeycombing, DEJ and dermal inflammation with an interface dermatitis pattern. Four patients with inactive GVHD (6 lesions) showed minimal inflammation. RCM and HP had similar detection rates for 6 of 13 features and overall patterns important for diagnosis in 2 patients with late aGVHD (2 lesions; 15%) and 10 with nonsclerotic cGVHD (11 lesions; 85%) necessitating skin biopsy. RCM can detect features commonly reported in cutaneous GVHD and is comparable to HP. Additional characterization of cutaneous GVHD by RCM may enable future use in diagnosing, monitoring, or predicting disease in real time.

Acute Radiation Dermatitis Evaluation with Reflectance Confocal Microscopy: A Prospective Study

Background: During radiotherapy (RT), most breast cancer patients experience ionizing radiation (IR)-induced skin injury—acute radiation dermatitis (ARD). The severity of ARD is determined by a physician according to CTCAE or RTOG scales, which are subjective. Reflectance confocal microscopy (RCM) is a noninvasive skin imaging technique offering cellular resolution. Digital dermoscopy (DD) performed in conjugation with RCM can provide more information regarding skin toxicity. The purpose of this study is to create an RCM and DD features-based ARD assessment scale, to assess the association with CTCAE scale and possible predictive value. Methods: One hundred and three breast cancer patients during RT were recruited; every week, clinical symptoms of ARD (CTCAE scale) were evaluated and RCM, together with digital dermoscopy (DD), was performed. Results: According to RCM; after 2 RT weeks, exocytosis and/or spongiosis were present in 94% of patients; after 3 weeks, mild contrast cells (MMCs) were detected in 45%; disarrayed epidermis (DE) was present in 66% of patients after 4 weeks and in 93% after 5 weeks; abnormal dermal papillae (ADP) were present in 68% of patients after 5 weeks. The coefficients of RCM features (RCM_coef) alone and together with dermoscopically determined erythema (RCM-ERY_coef) were significantly associated with ARD severity grade. RCM_coef is a significant predictive factor for the clinical manifestation of ARD. Conclusions: RCM features of irradiated skin appear earlier than clinical symptoms, have a characteristic course, and allow the severity of ARD to be predicted.

Dynamic evaluation of an in vivo postinflammatory hyperpigmentation model using reflectance confocal microscopy and spectrophotometry

BACKGROUND

Postinflammatory hyperpigmentation (PIH) reflects a dynamic process from primary injury and cutaneous inflammation to subsequent melanogenesis and hyperpigmentation, of which pathogenesis remains unclear, hindering the development of targeted therapies.

AIMS

To observe the dynamic development of PIH; determine the starting point and peak point of the inflammatory phase and pigmentary phase; and clarify the timing of anti-inflammatory and anti-pigmentary treatment.

METHODS

Thirty healthy volunteers with Fitzpatrick skin types III-IV were enrolled and underwent suction blisters. The noninvasive evaluation of inflammation and hyperpigmentation on suction blister sites were performed via spectrophotometry (CM2600d and SIAscope) and RCM for the following 24 weeks.

RESULTS

We successfully observed suction blister-induced PIH lasting over 24 weeks. The inflammatory phase started soon after the procedure and lasted for 8-12 weeks, manifested by significantly elevated a* values and erythema index detected by spectrophotometry, as well as inflammatory infiltration and angiogenesis shown in RCM images. Meanwhile, melanogenesis was accelerated after week 3 and reached peak on week 8, manifested by significantly accumulated melanin granules and bright pigment rings in different depths under RCM, which was in parallel with elevated melanin index. The darkening skin tone in PIH actually presented a mixture of inflammatory erythema, angiogenesis, and hyperpigmentation. The inflammation and pigmentation phases of PIH were not sequential but partially overlap.

CONCLUSION

The duration of suction blister-induced PIH is more than 24 weeks. The inflammatory phase partially overlaps with the pigmentary phase, and those drugs with anti-inflammatory and anti-pigmentary dual effects are potential choices.

Reflectance Confocal Microscopy, Optical Coherence Tomography, and Multiphoton Microscopy in Inflammatory Skin Disease Diagnosis

BACKGROUND AND OBJECTIVES

Technological advances in medicine have brought about many novel skin imaging devices. This review aims to evaluate the scientific evidence supporting the use of noninvasive optical imaging techniques to aid in the diagnosis and prognosis of inflammatory skin diseases.

STUDY DESIGN/MATERIALS AND METHODS

PubMed and Scopus were searched in September 2020 according to PRISMA guidelines for articles using reflectance confocal microscopy (RCM), optical coherence tomography (OCT), and multiphoton microscopy (MPM) in inflammatory skin diseases, excluding studies monitoring treatment efficacy.

RESULTS

At the time of the study, there were 66 articles that addressed the utilization of noninvasive imaging in interface, spongiotic, psoriasiform, vesiculobullous, and fibrosing/sclerosing inflammatory skin dermatoses: RCM was utilized in 46, OCT in 16, and MPM in 5 articles. RCM was most investigated in psoriasiform dermatoses, whereas OCT and MPM were both most investigated in spongiotic dermatoses, including atopic dermatitis and allergic contact dermatitis.

CONCLUSIONS

There is preliminary evidence to support the diagnostic potential of noninvasive optical imaging techniques in inflammatory skin diseases. Improvements in the devices and further correlation with histology will help broaden their utility. Additional studies are needed to determine the parameters for diagnostic features, disease differentiation, and staging of inflammatory skin conditions. Lasers Surg. Med. © 2021 Wiley Periodicals LLC.

Non infective bullous lesions: a diagnostic challenge in a minimally equipped centre- based solely on microscopic findings

Vesicobullous lesions of skin may occur in different forms of dermatosis, which include various inflammatory, infective, autoimmune, drug induced as well as genetic conditions. Autoimmune bullous lesions, may be fatal if not treated with appropriate agents. Bearing in mind, the morbidity of these diseases, it is important to establish a firm diagnosis. A diagnostic skin biopsy with immunofluorescence is frequently used to confirm a clinical diagnosis, especially where it is not apparent clinically. There are many centres in India where immunofluorescence is not available and the diagnosis in these lesions is based on clinical and histopathological features only. Here in this study, we studied 53 skin punch biopsies with clinical suspicion of vesicobullous lesions followed by histopathological examination was carried out over a period of 2 years in a Medical College in Gujarat. Lesions were categorised based on the location of the blister. 1) Suprabasal 2) subcorneal 3) and subepidermal. Further subtyping was done based on additional histopathological features and clinical correlation. All the patients responded appropriately to the treatment and the results correlated well with the immunofluorescence done in a few cases. This study lays emphasis upon the histopathology and clinical features keeping in consideration of the lack of ancillary techniques in many centres especially in the developing world.

In Vivo Reflectance Confocal Microscopy: Emerging Role in Noninvasive Diagnosis and Monitoring of Eczematous Dermatoses

Dermatologic diagnosis and monitoring have been dependent largely on visual grading. A skin biopsy is performed in case of diagnostic uncertainty, but can be traumatic, and results are delayed due to time for specimen transport and processing. Biopsies also destroy specimens, prohibiting lesion evolution monitoring. In vivo reflectance confocal microscopy (RCM) offers a diagnostic alternative to skin biopsy. RCM captures real-time, high-resolution images, and has been piloted for the evaluation of various dermatologic conditions. Identification of unique RCM features may distinguish dermatoses with similar clinical morphologies. Allergic contact dermatitis (ACD) and irritant contact dermatitis (ICD) are diagnosed by patch testing that currently uses a subjective scoring system. RCM has increasingly been studied for early detection and severity grading of CD. Common RCM features shared by ACD and ICD are stratum corneum disruption, vesicle formation, exocytosis, spongiosis, and parakeratosis. Features unique to ACD are vasodilation, increased epidermal thickness, intercellular edema, and acanthosis. Features unique to ICD are detached corneocytes and targetoid keratinocytes. This review summarizes the use of RCM in evaluating contact eccematous conditions and aims to spark future research and interest in this promising tool.

Skin Biophysical Parameters and Patch Test Results in People Predisposing to Xiaotong Tiegao Induced Irritant Contact Dermatitis

Background

Xiaotong Tiegao (XTT) is an ancient topical Tibetan medicine plaster which is widely used in China. Irritant contact dermatitis (ICD) caused by XTT is very common. It is still unclear why some people are more prone to develop ICD. The aim of this study is to study the baseline skin biophysical parameters and patch test results in individuals predisposing to XTT induced ICD.

Methods

During a four-month period, 149 healthy volunteers with ICD and 50 volunteers without ICD after applying XTT were recruited. The skin biophysical parameters were measured, and contact allergy to 20 common allergens was patch tested, at two weeks after the ICD was recovered.

Results

There were no significant differences in age and sex between ICD and control groups. It was found that skin median melanin value (176.50 vs 189.50, P < 0.05, Mann-Whitney U-test) and erythema value (319.90 ± 70.49 vs 347.93 ± 84.55, P < 0.05, Independent-Samples T test) were much lower in ICD than control group. Overall patch test results were not different, but the positivity rate of nickel sulfate (15.44% vs 4.00%, P < 0.05, Fisher's exact test) was significantly higher in ICD group.

Conclusions

In conclusion, people with nickel allergy, lower values of skin melanin, and erythema are predisposing to develop ICD.

A minimally invasive tool to study immune response and skin barrier in children with atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) affects children of all skin types. Most research has focused on light skin types. Studies investigating biomarkers in people with AD with dark skin types are lacking.

OBJECTIVES

To explore skin barrier and immune response biomarkers in stratum corneum (SC) tape strips from children with AD with different skin types.

METHODS

Tape strips were collected from lesional and nonlesional forearm skin of 53 children with AD and 50 controls. We analysed 28 immunomodulatory mediators, and natural moisturizing factors (NMF) and corneocyte morphology.

RESULTS

Interleukin (IL)-1β, IL-18, C-X-C motif chemokine (CXCL) 8 (CXCL8), C-C motif chemokine ligand (CCL) 22 (CCL22), CCL17, CXCL10 and CCL2 were significantly higher (P < 0·05) in lesional AD skin compared with nonlesional AD skin; the opposite trend was seen for IL-1α. CXCL8, CCL2 and CCL17 showed an association with objective SCORing Atopic Dermatitis score. NMF levels showed a gradual decrease from healthy skin to nonlesional and lesional AD skin. This gradual decreasing pattern was observed in skin type II but not in skin type VI. Skin type VI showed higher NMF levels in both nonlesional and lesional AD skin than skin type II. Corneocyte morphology was significantly different in lesional AD skin compared with nonlesional AD and healthy skin.

CONCLUSIONS

Minimally invasive tape-stripping is suitable for the determination of many inflammatory mediators and skin barrier biomarkers in children with AD. This study shows differences between children with AD with skin type II and skin type VI in NMF levels, suggesting that some aspects of pathophysiological mechanisms may differ in AD children with light versus dark skin types.

Label-free microscopic assessment of glioblastoma biopsy specimens prior to biobanking [corrected]

Glioblastoma is the most common primary brain tumor with a median 12- to 15-month patient survival. Improving patient survival involves better understanding the biological mechanisms of glioblastoma tumorigenesis and seeking targeted molecular therapies. Central to furthering these advances is the collection and storage of surgical biopsies (biobanking) for research. This paper addresses an imaging modality, confocal reflectance microscopy (CRM), for safely screening glioblastoma biopsy samples prior to biobanking to increase the quality of tissue provided for research and clinical trials. These data indicate that CRM can immediately identify cellularity of tissue biopsies from animal models of glioblastoma. When screening fresh human biopsy samples, CRM can differentiate a cellular glioblastoma biopsy from a necrotic biopsy without altering DNA, RNA, or protein expression of sampled tissue. These data illustrate CRM's potential for rapidly and safely screening clinical biopsy samples prior to biobanking, which demonstrates its potential as an effective screening technique that can improve the quality of tissue biobanked for patients with glioblastoma.

Pathogenesis and diagnosis of contact dermatitis: Applications of reflectance confocal microscopy

Contact dermatitis (CD) is the most common professional skin disease, with frequencies ranging from 24 to 170 every 100000 individuals. Approximately 20% of the United States population suffers from CD. CD can be classified according to its origin and severity. ICD stands for irritant CD, whereas ACD means allergic CD. Their clinical presentation includes acute, sub-acute and chronic eczema. Despite their different origin, ICD and ACD often present similar clinical and histologic findings. The current gold standard for diagnosis is patch-testing. However, patch-testing is being questioned in terms of validity and reproducibility, as it relies heavily on the skill of the observer. Real-time reflectance confocal microscopy is a non-invasive imaging technique that bears strong promise for the study of CD, and it enables the evaluation of cellular and subcellular changes over time with similar resolution compared to that of conventional histology.

Neurosurgical confocal endomicroscopy: A review of contrast agents, confocal systems, and future imaging modalities

Background:

The clinical application of fluorescent contrast agents (fluorescein, indocyanine green, and aminolevulinic acid) with intraoperative microscopy has led to advances in intraoperative brain tumor imaging. Their properties, mechanism of action, history of use, and safety are analyzed in this report along with a review of current laser scanning confocal endomicroscopy systems. Additional imaging modalities with potential neurosurgical utility are also analyzed.

Methods:

A comprehensive literature search was performed utilizing PubMed and key words: In vivo confocal microscopy, confocal endomicroscopy, fluorescence imaging, in vivo diagnostics/neoplasm, in vivo molecular imaging, and optical imaging. Articles were reviewed that discussed clinically available fluorophores in neurosurgery, confocal endomicroscopy instrumentation, confocal microscopy systems, and intraoperative cancer diagnostics.

Results:

Current clinically available fluorescent contrast agents have specific properties that provide microscopic delineation of tumors when imaged with laser scanning confocal endomicroscopes. Other imaging modalities such as coherent anti-Stokes Raman scattering (CARS) microscopy, confocal reflectance microscopy, fluorescent lifetime imaging (FLIM), two-photon microscopy, and second harmonic generation may also have potential in neurosurgical applications.

Conclusion:

In addition to guiding tumor resection, intraoperative fluorescence and microscopy have the potential to facilitate tumor identification and complement frozen section analysis during surgery by providing real-time histological assessment. Further research, including clinical trials, is necessary to test the efficacy of fluorescent contrast agents and optical imaging instrumentation in order to establish their role in neurosurgery.

Application of Confocal Laser Scanning Microscopy in Biology and Medicine

Fluorescence confocal laser scanning microscopy and reflectance confocal laser scanning microscopy are up-to-date highend study methods. Confocal microscopy is used in cell biology and medicine. By using confocal microscopy, it is possible to study bioplasts and localization of protein molecules and other compounds relative to cell or tissue structures, and to monitor dynamic cell processes. Confocal microscopes enable layer-by-layer scanning of test items to create demonstrable 3D models. As compared to usual fluorescent microscopes, confocal microscopes are characterized by a higher contrast ratio and image definition.

Optical techniques for the noninvasive diagnosis of skin cancer

PURPOSE

The aim of this paper is to provide an overview of the most investigated optical diagnostic techniques: optical coherence tomography, fluorescence spectrometry, reflectance spectrometry, Raman spectroscopy, and confocal microscopy.

METHODS

A search of three databases was conducted using specific keywords and explicit inclusion and exclusion criteria for the analysis of the performances of these techniques in the pre- and postoperative diagnosis of skin cancers.

RESULTS

Optical coherence tomography has shown promising results in the assessment of deep margins of skin tumors and inflammatory skin diseases, but differentiating premalignant from malignant lesions proved to be less effective. Fluorescence spectroscopy proved to be effective in revealing the biochemical composition of tissue; early detection of malignant melanoma was reliable only with stepwise two-photon excitation of melanin, while tumoral margin assessment and differential diagnosis between malignant and non-malignant lesions showed some conflicting results. Characterization of the structural properties of tissue can be made using diffuse reflectance spectrometry, and the values of the specificity and sensitivity of this method are ranging between 72-92 % and 64-92 %, respectively. Raman spectroscopy proved to have better results both in carcinoma and melanoma diagnosis with sensitivities and specificities above 90 % and high above 50 %, respectively. Confocal microscopy is the closest technique to pathological examination and has gained the most clinical acceptance, despite the need for a standardization of the interpretation algorithm.

CONCLUSIONS

In conclusion, these optical techniques proved to be effective in the diagnosis of skin cancer, but further studies are needed in finding the appropriate method or combination of methods that can have wide clinical applications.

High-definition optical coherence tomography: adapted algorithmic method for pattern analysis of inflammatory skin diseases: a pilot study

High-definition optical coherence tomography (HD-OCT) is a non-invasive technique for morphological investigation of tissue with cellular resolution filling the imaging gap between reflectance confocal microscopy and conventional optical coherence tomography. The aim of this study is first to correlate dermatopathologic descriptors of inflammatory skin conditions with epidermal alteration to features observed by HD-OCT. Secondly, to assess the discriminative accuracy of common inflammatory reaction patterns with epidermal alteration using HD-OCT by applying Ackerman’s algorithmic method of pattern recognition. The generated HD-OCT images of 160 patients presenting an inflammatory skin disease were analyzed with respect to the following criteria: visualization of individual cells in the epidermis and dermis and morphology of dermo-epidermal junction, papillary dermis and reticular dermis. A set of morphological features corresponding to dermatopathological descriptors are obtained and the discriminative accuracy of HD-OCT of inflammatory reaction patterns could be demonstrated. These patterns are spongiotic dermatitis, psoriasiform dermatitis, interface dermatitis and ballooning dermatitis. Additional studies to test the sensitivity and specificity of the proposed algorithm for pattern analysis are essential. The other categories of Ackerman’s pattern recognition need to be evaluated. This study provides a set of morphological features generated by HD-OCT imaging very similar to those described for reflectance confocal microscopy but with the advantages not only to visualize individual cells up to a depth of 570 μm but also in both slice and en face mode. An adapted algorithmic method for pattern analysis of common inflammatory skin diseases could be proposed. This new technique appears to be a promising method for non-invasive diagnosis, evaluation and management of common inflammatory skin diseases.

Skin from various ethnic origins and aging: an in vivo cross-sectional multimodality imaging study

BACKGROUND

Ethnic differences in skin structural features have not been thoroughly investigated, and the few reported studies are contradictory. Thus, we have carried out a set of in vivo measurements on the skin of about 400 volunteers from various ethnic origins living in the same environment.

METHODS

Female subjects were distributed into four ethnic groups: African Americans, Mexicans, Caucasians, and Chinese. Inter- and intra-ethnic skin structural differences, according to age and anatomic site, were investigated using three non-invasive skin-imaging methods: ultrasound (US) at 25 and 150 MHz, and optical coherence tomography (OCT).

RESULTS

The thickness of the skin is higher on the cheek compared with the dorsal and ventral forearm, with no ethnic or age-related specificity. We confirm that the sub-epidermal non-echogenic band is a sensitive marker of skin aging, and reveal for the first time that it is less pronounced in African Americans. From OCT images, we bring out evidence that the thickness of the dermal-epidermal junction (DEJ) decreased with age, and was higher in African Americans than in Caucasians. Finally, by comparing US images at 150 MHz with OCT images, we show that papillary dermis thickness can be measured and appears to be quite constant irrespective of age or ethnic group.

CONCLUSION

Our study confirms that skin imaging is very attractive to further our knowledge of the morphology of skin from various ethnic origins. Regarding age effects, quantitative parameters have shown that they would be delayed in African Americans compared with all other ethnic populations.

Skin irritation and sensitization: mechanisms and new approaches for risk assessment. 1. Skin irritation

Cutaneous irritation presents a major health problem with serious social and occupational impact. The interaction between an irritant and the human skin depends on multiple factors: the intrinsic properties and the nature of the irritant itself, and specific individual- and environment-related variables. The main pathological mechanisms of irritancy include skin barrier disruption, induction of a cytokine cascade and involvement of the oxidative stress network; all of them resulting in a visible or subclinical inflammatory reaction. In vivo, different non-invasive parameters for the evaluation of skin irritation and irritant potential of compounds and their specific formulations have been introduced, such as epidermal barrier function, skin hydration, surface pH, lipid composition, skin colour and skin blood flow. The diverse physiological changes caused by irritating agents require implementation of a multiparametric approach in the evaluation of cutaneous irritancy.

In vivo reflectance-mode confocal microscopy in clinical dermatology and cosmetology

In vivo reflectance confocal microscopy (RCM) is a non-invasive imaging tool that allows real-time visualization of cells and structures in living skin with near histological resolution. RCM has been used for the assessment of benign and malignant lesions, showing great potential for applications in basic skin research and clinical dermatology. RCM also reveals dynamic changes in the skin over time and in response to specific stimuli, like ultraviolet exposure, which makes it a promising tool in cosmetology, as it allows repetitive sampling without biopsy collection, causing no further damage to the areas under investigation. This review summarizes the latest advances in RCM, and its applications in the characterization of both normal and pathological skin.

Real-time imaging and characterization of human breast tissue by reflectance confocal microscopy

Real-time technologies can increase the efficiency of obtaining informative biopsies and accelerate interpretation of biopsy pathological review. Cellular aberrations inherent to cancer cells, including nuclear size, can currently be detected, but few technologies are available to evaluate adequacy of specimens in real time. The aims of this study are: 1. to determine if near-infrared reflectance confocal microscopy (RCM) can be used to assess epithelial/stromal content of core needle breast biopsy samples in real time, 2. to determine if epithelial cell nuclear size can be measured on RCM images, and 3. to test if RCM images can be accurately read for presence/absence of histologically relevant features of malignancy. Breast biopsies are obtained following a medically indicated breast core needle diagnostic biopsy for RCM examination. Acetic acid is used as a contrast agent to visualize structures within breast tissue. Structures are identified and optically serially sectioned, and digital images are cataloged. Relative amounts of epithelial, fatty, and collagenous tissue are determined. RCM biopsies are formalin-fixed and stained for hematoxylin and eosin (H and E) comparison with RCM images. RCM data are comparable to data from H and E sections. Epithelial cell nuclear size is measured on stored digital RCM images. We compare RCM and H and E images from 16 patients and 25 core needle biopsy samples.

Noninvasive evaluation of allergic and irritant contact dermatitis by in vivo reflectance confocal microscopy

BACKGROUND

The clinical differentiation of allergic contact dermatitis (ACD) and irritant contact dermatitis (ICD) is often difficult to accomplish. Reflectance-mode confocal microscopy (RCM) is an imaging technique that has previously been used to examine ACD and ICD noninvasively in vivo.

OBJECTIVE

To determine characteristic features of ACD and ICD and their kinetic evolution over time. Ethnic susceptibility to contact irritants such as sodium lauryl sulfate and Ivory dishwashing liquid was evaluated noninvasively, and the sensitivity and specificity of RCM parameters were analyzed in a clinical context and in reference to patch testing.

METHODS

Subjects were patch-tested with allergens, irritants, and controls. Clinical scoring and RCM evaluation were performed at various time points, assessing stratum corneum (SC) disruption, spongiosis, exocytosis, vesicle formation, and epidermal thickness.

RESULTS

RCM features of both ACD and ICD include spongiosis, exocytosis, vesicle formation, and blood vessel dilatation. SC disruption, epidermal necrosis, and hyperproliferation are hallmarks of ICD whereas ACD more typically presents with vesicle formation. Patients with ICD showed a more rapid recovery than those with ACD. When tested with Ivory soap at selected concentrations, Caucasians, when compared to African Americans, showed significantly lower clinical thresholds for ICD and features that were more severe.

CONCLUSIONS

RCM may be a promising new technology for longitudinal noninvasive studies of contact dermatitis (CD). Using a diagnostic algorithm and those parameters with high sensitivity for CD, RCM may facilitate the differentiation of acute ACD and ICD. RCM can reliably visualize cutaneous changes at subclinical degrees of CD, which suggests a possible role for RCM as an adjunctive tool in CD diagnosis. The results of this pilot study also indicate ethnic differences in the response to contact irritants. However, further studies are needed to substantiate the relevance and clinical applicability of our findings.

Influence of usage practices, ethnicity and climate on the skin compatibility of sanitary pads

Modern disposable sanitary pads are becoming available worldwide. Regional differences in usage practices, ethnicity, and climate may influence their skin compatibility. Pad usage practices depend on culture, economics, and menstrual physiology. Daily usage is higher in Japan and but lower in Nigeria compared to North America or Western Europe. Evidence for ethnic differences in skin irritant susceptibility is not compelling. Dark skin may be less susceptible to certain irritants than fair skin; the Japanese may experience a higher degree of sensory irritation than Caucasians. Ambient conditions such as high temperature and humidity increase the skin temperature and skin surface moisture under sanitary pads by small but measurable amounts, causing no discernible skin irritation; vapor-permeable pad backings reduce these effects. Cold dry conditions, which can irritate exposed skin, may not affect vulvar skin to the same degree due to its elevated hydration and occlusion. To address the practical significance of these variables, results of prospective clinical trials of sanitary pads performed by industry and academic scientists in North America (Indiana), Mexico, Western Europe (Munich, Athens, Goteborg, Sweden), Eastern Europe (Kiev) and Africa (Abuja, Nigeria) were reviewed. Despite the diverse range of conditions, no significant adverse skin effects were observed with modern pads compared to traditional pad designs. Study participants generally preferred modern pads for performance and comfort.

In vivo confocal scanning laser microscopy in dermatology

The need to improve the diagnostic accuracy and sensitivity for skin tumours has led to the development of new non-invasive, in vivo techniques including ultrasound, dermoscopy, digital photography, confocal scanning laser microscopy, magnetic resonance imaging and optical coherence tomography. Of all these in vivo techniques, only confocal scanning laser microscopy allows for the examination of the epidermis and papillary dermis at a resolution approaching histological detail. This review article looks at some of the most important applications of this new technology, highlighting its qualities and limitations.

Pilot study on the sensitivity and specificity of in vivo reflectance confocal microscopy in the diagnosis of allergic contact dermatitis

The validity, reproducibility, and specificity of patch-testing in the diagnosis of allergic contact dermatitis (ACD) have repeatedly been addressed. In vivo reflectance confocal microscopy (RCM) has been used for real-time evaluation of the histopathologic features of ACD. This pilot study was designed to determine the sensitivity and specificity of RCM in diagnosing ACD in reference to patch-testing. Sixteen participants were patch tested with allergens and control substances. Clinical scoring, digital photography, and RCM evaluation were performed at 72 hours, and RCM images were subjected to blinded evaluation. RCM evaluation parameters included stratum corneum (SC) disruption, parakeratosis, stratum spinosum (SS) and stratum granulosum (SG) spongiosis, and exocytosis. Overall, there was high specificity for all RCM features, ranging from 95.8% to 100%. Sensitivity ranged from 51.9% to 96.3%. Significant parameters with high sensitivity and specificity included spongiosis and exocytosis at the level of SS. Logistic regression analysis was performed on significant variables; P values were determined by chi2 analysis. RCM is a promising noninvasive technology for the evaluation of ACD. SC changes are not helpful in the diagnosis of ACD, although the presence of SG spongiosis and SS spongiosis shows high sensitivity in diagnosing ACD. Larger sensitivity and specificity studies are needed and the identification of ACD has to be based on a defined diagnostic algorithm. A limitation of this study is the small sample size; larger sensitivity and specificity studies are needed to confirm these findings. In addition, individual allergens have to be subjected to further evaluations in order to demonstrate the applicability of our findings for other contact allergens. In that regard, RCM may be considered as an adjunctive tool, rather than a substitute, to clinical evaluation.

Irritant contact dermatitis induced by a common household irritant: A noninvasive evaluation of ethnic variability in skin response

OBJECTIVE

This study was undertaken to investigate the ethnic susceptibility to irritant contact dermatitis induced by a common dishwashing liquid using noninvasive technologies.

METHODS

A total of 30 participants (15 Caucasian, 15 African American) were patch tested to graded concentrations of a common household irritant and evaluated using clinical scoring, reflectance confocal microscopy, transepidermal water loss, and fluorescence excitation spectroscopy.

RESULTS

At 24 hours, the concentration thresholds for clinically perceptible irritancy were significantly higher for African American compared with Caucasian participants. Reflectance confocal microscopy showed stratum corneum disruption, parakeratosis, and spongiosis; these features were more severe in Caucasian participants (P < or = .002). Mean values for transepidermal water loss were significantly higher in the Caucasian group at comparable clinical scores (P < or = .005). Fluorescence excitation spectroscopy showed a broad excitation band at 300 nm (emission 340 nm) and values in both groups returned to baseline by day 7.

LIMITATIONS

This pilot study was limited in scope and larger studies are needed to further evaluate ethnic differences in irritant contact dermatitis and to demonstrate the applicability of our findings for other irritants.

CONCLUSION

Clinical evaluation, reflectance confocal microscopy, and transepidermal water loss showed significant differences in the cutaneous irritant response between both groups suggesting a superior barrier function of African American skin. Fluorescence excitation spectroscopy on the other hand demonstrated no differences in the hyperproliferative response after irritant exposure and indicated similar kinetics for the two groups.

Reflectance confocal microscopy for characterization of mammary ductal structures and development of neoplasia in genetically engineered mouse models of breast cancer

The earliest steps of breast cancer begin with aberrations in mammary ductal structure. Techniques that enable an investigator to image in situ and then analyze the same tissue using biochemical tools facilitates identification of genetic networks and signaling pathways active in the imaged structure. Cellular confocal microscopy (VivaCell-TiBa, Rochester, New York) is used to image mammary ductal structures and surrounding vasculature in situ in intact wild-type and genetically engineered mice that develop ER alpha-initiated ductal carcinoma in situ (DCIS) and ER alpha-driven invasive mammary cancer. In wild-type mice, normal mammary ductal structures that appear from puberty through lactation are visualized and serially sectioned optically, and a developmental atlas is created. Altering tissue preparation enabled visualization of the vasculature surrounding the ductal structures. In the genetically engineered mice, aberrant mammary ductal structures and cancers are imaged and compared to corresponding normal structures. Different preparation techniques are able to preserve tissue for routine histological analyses and RNA isolation. Comparative studies demonstrate that reflectance confocal imaging provides more cellular detail than carmine-alum-stained mammary gland whole mounts and equivalent detail with hematoxylin and eosin stained tissue sections. In summary, reflectance confocal microscopy is a tool that can be used to rapidly and accurately analyze mammary gland structure.

In vivo assessment of melanocytic nests in nevi and melanomas by reflectance confocal microscopy

In vivo reflectance confocal microscopy is a novel technique for the noninvasive study and diagnosis of the skin. The aim of this study was to describe and characterize the cytological and architectural aspects of cell clusters in melanocytic lesions observed by confocal microscopy, and to correlate them with routine histopathology. A total of 55 melanocytic lesions comprising 20 melanomas, 25 acquired nevi and 10 Spitz nevi were studied by means of reflectance confocal microscopy, dermoscopy and routine histopathology. Three different types of cell clusters at confocal microscopy observation (dense, sparse cell and cerebriform clusters) were identified and correlated with histopathology. Dense clusters appeared characteristic for benign lesions, although present in 13 out of 20 melanomas. Sparse cell clusters were more frequently observable in melanomas, but also sporadically present in one Spitz nevus. Moreover, cerebriform clusters were exclusively observed in five out of 20 melanomas. Confocal microscopy allowed the in vivo characterization of aspects of melanocytic nests and their exact correlation with histopathology.

Non-invasive evaluation of the kinetics of allergic and irritant contact dermatitis

Reflectance confocal microscopy (RCM) allows non-invasive visualization of human skin in vivo. It has been used to describe the histopathological features of acute contact dermatitis (CD). This work was designed to investigate the kinetics of both allergic and irritant CD (ACD and ICD) in vivo. Eighteen subjects with a prior diagnosis of ACD were patch tested with the specific allergen sodium lauryl sulfate as an irritant, and appropriate controls. RCM, transepidermal water loss (TEWL), and fluorescence excitation spectroscopy (FES) were performed at several time points within 2 wk after patch removal. After removal of the Finn chambers at 48 h, superficial epidermal changes, primarily involving the stratum corneum, and increased epidermal thickness were mainly present in ICD. ACD, on the other hand, showed microvesicle formation peaking at 96 h following patch removal. Both ACD and ICD showed exocytosis and similar degrees of spongiosis on RCM. TEWL and FES demonstrated a significant difference between ACD and ICD. RCM, TEWL, and FES are valuable non-invasive tools to quantitatively study the kinetics of the pathophysiology of acute CD reactions in vivo and monitor the changes at a cellular level.

Changing paradigms in dermatology: confocal microscopy in clinical and surgical dermatology

The current practice of pathology and dermatopathology depends upon the evaluation of tissue in some manner extirpated from the patient and then processed and stained. While high resolution of detail can be accomplished by this method, there are certain risks and disadvantages. Recent imaging techniques now allow for a potential of achieving noninvasive high-resolution analysis of lesions in situ in the patient. Of these, Reflectance mode confocal microscopy offers the highest resolution imaging comparable to routine histology. Being entirely non invasive, skin can be observed in its native, dynamic state. This chapter will review the fundamentals of in vivo confocal imaging and the clinical applications in general and surgical dermatology.

Reflectance confocal microscopy may differentiate acute allergic and irritant contact dermatitis in vivo

BACKGROUND

Acute irritant contact dermatitis (ICD) and allergic contact dermatitis (ACD) may be difficult to distinguish by clinical or histologic assessment. Reflectance confocal microscopy (RCM) enables real-time, high-resolution skin imaging in vivo.

OBJECTIVE

We sought to image, characterize, and distinguish acute ACD and ICD in vivo.

METHODS

Volunteers with ACD were patch tested with an allergen and the irritant, sodium lauryl sulfate. RCM imaging and transepidermal water loss measurements were performed at 24 and 72 hours. Biopsy specimens were correlated with RCM images.

RESULTS

Spongiosis, epidermal inflammatory cell infiltrate, and vesicle formation were observed in ACD and ICD. Compared with ACD, ICD showed greater disruption of the stratum corneum, and more parakeratosis. There was a significantly greater increase in transepidermal water loss for ICD compared with ACD.

CONCLUSION

RCM is a promising tool for dynamic, noninvasive assessment and may help to differentiate acute ACD and sodium lauryl sulfate-induced ICD.

Changing paradigms in dermatology: new ways to examine the skin using noninvasive imaging methods

Detailed visualization of the skin in the practice of dermatology is key to a comprehensive examination and accurate diagnosis. Advancements in digital dermoscopy, microscopy, imaging and photography have formed an impressive arsenal with which dermatologists can offer state-of-the-art patient care while streamlining their clinical practice and improving their academic and research capacities. Many types of advanced imaging are used in the biologic sciences at the bench; however, our paper reviews the clinical, noninvasive in vivo human applications of these emerging technologies. Our experiences with these instruments reinforce such reviews.