Biopsy outperforms reflectance confocal microscopy in diagnosing and subtyping basal cell carcinoma: results and experiences from a randomized controlled multicentre trial.

BACKGROUND: Reflectance confocal microscopy (RCM) is a noninvasive method for skin assessment, allowing entire lesion evaluation up to the papillary dermis. RCM is a potentially attractive alternative to punch biopsy (PB) in basal cell carcinoma (BCC). OBJECTIVES: To determine the diagnostic accuracy of RCM vs. PB in diagnosing and subtyping BCC, and to study patient satisfaction and preferences. METHODS: Patients with a clinically suspected primary BCC were randomized between RCM and biopsy. Conventional surgical excision or follow-up were used as reference. Sensitivity and specificity for BCC diagnosis and subtyping were calculated for both methods. BCC subtype was stratified based on clinical relevance: aggressive (infiltrative/micronodular) vs. nonaggressive (superficial/nodular) histopathological subtype and superficial vs. nonsuperficial BCC. Data on patient satisfaction and preferences were collected using a questionnaire and a contingent valuation method. RESULTS: Sensitivity for BCC diagnosis was high and similar for both methods (RCM 99·0% vs. biopsy 99·0%; P = 1·0). Specificity for BCC diagnosis was lower for RCM (59·1% vs. 100·0%; P < 0·001). Sensitivity for aggressive BCC subtypes was lower for RCM (33·3% vs. 77·3%; P = 0·003). Sensitivity for nonsuperficial BCC was not significantly different (RCM 88·9% vs. biopsy 91·0%; P = 0·724). Patient satisfaction and preferences were good and highly comparable for both methods. CONCLUSIONS: Biopsy outperforms RCM in diagnosing and subtyping clinically suspected primary BCC. This outcome does not support routine clinical implementation of RCM, as a replacement for PBs in this patient group.

Noninvasive objective skin measurement methods for rosacea assessment: a systematic review.

BACKGROUND: Rosacea assessment and therapy monitoring can be challenging to standardize, as most clinical evaluation systems are prone to interobserver variability and not always validated. Therefore, objective, reliable and preferably noninvasive measurement tools are needed. OBJECTIVES: To give insight into available noninvasive imaging techniques and biophysical methods in rosacea by performing a systematic review. METHODS: PubMed, Embase, Cochrane and Web of Science databases were searched until 1 September 2018 in accordance with PRISMA guidelines, to identify studies providing original data about objective noninvasive imaging and/or biophysical skin measurement techniques for diagnosis, assessing severity or therapy monitoring of adult patients with cutaneous facial rosacea. Risk of bias of included articles was assessed with the Cochrane Risk of Bias tool, Quality in Prognosis Studies tool, and the Newcastle-Ottawa Scale. RESULTS: A total of 78 studies were included, describing 14 imaging and biophysical methods. Widespread information about (sub)surface cutaneous morphology and functionality was obtained. Methodological study quality was relatively low and interstudy outcome variability was large. Several tools show promising value in research settings: for treatment follow-up Demodex mites are countable with reflectance confocal microscopy, spectrometry can quantify erythema, and rosacea severity could be objectified with skin hydration- and transepidermal water loss measurements. CONCLUSIONS: This systematic review describes the spectrum of noninvasive imaging and biophysical methods in rosacea assessment, giving multifaceted information about structure and properties of rosacea skin, especially useful for research purposes. Larger studies with good methodological quality are needed to create validated protocols for further implementation into research. What's already known about this topic? Rosacea is a chronic inflammatory skin disease with a variety of clinical manifestations. Most clinical evaluation systems are subjective, not always validated, and subsurface skin processes remain unnoticed. Currently, different types of noninvasive measurement tools are available for rosacea assessment and therapy monitoring, but a comprehensive overview is lacking. What does this study add? Seventy-eight publications were included, describing 14 imaging and biophysical tools, providing a wide range of information about rosacea skin morphology and functionality. Reflectance confocal microscopy and spectrometry are especially promising in therapy monitoring and skin barrier measurements for rosacea severity assessment. Larger studies with better methodological quality are needed to create validated protocols for implementation into research.

Risk factors associated with sensitive skin and potential role of lifestyle habits: a cross-sectional study.

Sensitive skin (SS) is a widespread condition, but still not completely understood. To identify risk factors that increase the likelihood of SS, 258 women aged between 20 and 65 years old and resident in the Netherlands were surveyed by questionnaire, which included questions on sociodemographic characteristics (age group, Fitzpatrick skin type, hormonal status), health state (atopic predisposition, skin diseases) and lifestyle habits (history of smoking and of sun exposure, frequency of physical exercise). Analysis of the responses confirmed that atopic predisposition, presence of skin diseases and Fitzpatrick skin types I and II are risk factors significantly associated with SS. In addition, as current or past smoking and a history of low sun exposure showed a trend to increase the likelihood of reporting SS, we suggest that the potential role of lifestyle factors in the onset or exacerbation of SS should be investigated further.

Measurement of skin surface biomakers by Transdermal Analyses Patch following different in vivo models of irritation: a pilot study.

BACKGROUND/PURPOSE: FibroTx Transdermal Analyses Patch (TAP) is a novel technology for non-invasive measurements of protein biomarkers on the skin surface, in vivo. The aim of this study was to explore the potential of TAP in detecting skin surface biomarkers following mild perturbations, in vivo, using two experimental models: tape stripping, mimicking acute barrier disruption, and histamine iontophoresis, mimicking acute and local inflammation at minimal skin barrier insult. METHODS: Tape stripping and histamine iontophoresis were performed in two separate experiments on the volar forearm of healthy volunteers (n = 27 and n = 10, respectively). Biomarker levels were assessed with TAP at baseline and up to 72 h after stimulation. Functional (transepidermal water loss -TEWL- and a* value) and morphological (confocal reflectance microscopy -RCM) assessments were added in the tape stripping and histamine iontophoresis experiments, respectively. RESULTS: Cytokines IL-1α and IL-1RA and the antimicrobial peptide hBD-1 showed distinct dynamics, despite substantial inter-individual variation in levels, with an increase following tape stripping and a decrease following histamine iontophoresis. These dynamics could be related to the assessments made by TEWL and RCM. In the tape stripping experiment, additional biomarkers could be detected. CONCLUSION: TAP measurements, especially IL-1α, IL-1RA, and hBD-1, from the skin surface were sensitive enough for monitoring dynamic changes in the skin in the two models of skin perturbation. We conclude that TAP holds promise for non-invasively unraveling the dynamics of processes related to skin perturbation and repair.

A model for perception-based identification of sensitive skin.

BACKGROUND: With high prevalence of sensitive skin (SS), lack of strong evidence on pathomechanisms, consensus on associated symptoms, proof of existence of 'general' SS and tools to recruit subjects, this topic attracts increasing attention of research. OBJECTIVE: To create a model for selecting subjects in studies on SS by identifying a complete set of self-reported SS characteristics and factors discriminatively describing it. METHODS: A survey (n = 3058) was conducted, comprising questions regarding socio-demographics, atopy, skin characteristics, personal care, degree of self-assessed SS and subjective and objective reactions to endogenous and exogenous factors. Exploratory factor analysis on 481 questionnaires was performed to identify underlying dimensions and multivariate logistic regression to find contributing variables to the likelihood of reporting SS. RESULTS: The prevalence of SS was found to be 41%, and 56% of SS subjects reports a concomitant atopic condition. The most discriminative were the eliciting factors toiletries and emotions, and not specific skin symptoms in general. CONCLUSION: Triggers of different origins seem to elicit SS, it is not defined by concomitant skin diseases only, suggesting existence of 'general' SS. A multifactorial questionnaire could be a better diagnostic than a one-dimensional provocative test.

The influence of different shavers on the skin quantified by non-invasive reflectance confocal microscopy.

BACKGROUND: The impact of personal care devices on skin is mainly assessed using subjective tools. However, new objective, accurate non-invasive in vivo imaging techniques have been developed. The aim of this study was to evaluate the ability of reflectance confocal microscopy (RCM) in quantifying morphological impact of shavers on skin. Furthermore, tape stripping (TS) as method to study morphological impact of shavers was evaluated. METHODS: In 12 healthy male subjects, for two consecutive days, a split-face test was performed in the neck; on one side a shaver was applied, while the other side was exposed to TS. The stratum corneum (SC) thickness was quantified using RCM and sensory observations were evaluated using questionnaires. RESULTS: Shavers with a different impact on skin, can be discriminated by RCM; shaver B removed more SC after application than the skin friendlier shaver A. Furthermore, the changes in SC thickness induced by TS corresponded well to that of the shavers. CONCLUSION: RCM is able to quantify the impact of different shavers on skin. Besides, TS appeared to be a suitable model mimicking the mechanical impact of shavers on skin. RCM in combination with the TS model appeared to be a suitable minimally invasive model to obtain morphological and cell biological data on skin-material interactions caused by different personal care devices.

A four-phase strategy for the implementation of reflectance confocal microscopy in dermatology.

BACKGROUND: Reflectance confocal microscopy (RCM) is gradually implemented in dermatology. Strategies for further implementation and practical 'hands on' guidelines are lacking. OBJECTIVE: The primary outcome was to conduct a general strategy for further implementation of RCM. The secondary outcome was the diagnosis of psoriasis and differentiation of stable from unstable psoriatic plaques by means of the 'hands on' protocol, derived from the strategy. METHODS: We used a four-phased model; an exploring phase, a systematic literature search, a clinical approach and, finally, an integration phase to develop a clinical guideline for RCM in psoriasis. Receiver operating characteristic curve statistics was applied to define the accuracy for the diagnosis of unstable psoriasis. RESULTS: A general strategy for further implementation of RCM and practical approach was developed to examine psoriasis by RCM and to distinguish stable from unstable psoriasis. Unstable psoriasis was diagnosed by epidermal inflammatory cell counts with a sensitivity and specificity of 91.7% and 98.3%, respectively, and with an accuracy of 0.92 (area under the curve). In addition, a monitoring model was proposed. CONCLUSION: This is the first study that shows a method for implementation of RCM in dermatology. The strategy and hands on protocol for psoriasis may serve as a model for other dermatological entities and additionally may lead to specialized ready-to-use RCM protocols for clinical dermatological practice.

The value of in vivo reflectance confocal microscopy in the diagnosis and monitoring of inflammatory and infectious skin diseases: a systematic review.

In vivo examination of the skin by reflectance confocal microscopy (RCM) has been performed for about 20 years, leading to a broad spectrum of imaged infectious and inflammatory skin diseases (ISD) with many described RCM features. We systematically reviewed all available literature concerning ISD evaluated by RCM. Furthermore, we assessed the accuracy of the features and defined recommendations for future studies after indicating the limitations in the current published literature. PubMed, Embase, Cochrane Library and Web of Science databases were searched for literature. All studies on RCM and ISD were reviewed and quality assessment was determined by using the STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) checklist. The literature search revealed 77 eligible studies for inclusion. Different RCM features in a broad spectrum of ISD have been described. Further, RCM has been used for monitoring treatment and evolution of ISD, as well as for diagnostic purposes. This systematic review provides an overview of the broad spectrum of ISD imaged by RCM. Although RCM seems to be a promising monitoring and diagnostic tool for ISD, studies with appropriate methodological quality are necessary to create adequate guidelines and protocols for further implementation of RCM in clinical practice.

Application of leukotriene B4 and reflectance confocal microscopy as a noninvasive in vivo model to study the dynamics of skin inflammation.

BACKGROUND: Application of leukotriene B4 (LTB4) is an established in vivo model that locally induces skin inflammation. Currently in this model, a biopsy is inevitable. In vivo reflectance confocal microscopy (RCM), a noninvasive imaging technique, could overcome this limitation. To find out to what extent RCM may be an in vivo investigative and diagnostic tool in neutrophilic conditions, we studied the dynamics of polymorphonuclear leukocytes (PMN) migration from dermis to stratum corneum using an established LTB4 model. METHODS: Leukotriene B4 was topically applied on the skin of the lower back of seven volunteers. The skin sites were evaluated by RCM for three consecutive days with a 24 h time interval. For histological correlation, 3-mm punch biopsies were obtained. The tissue sections were hematoxylin-eosin and immunohistochemical stained. Minimal and average epidermal thickness was measured. RESULTS: Reflectance confocal microscopy imaging showed highly reflective ill-defined particles with a granular content throughout the epidermis 24 h after application of LTB4. Over time, the appearance of these cells changed throughout the epidermis. Epidermal thickness increased over time, and the measurements based on the RCM images corresponded very well with the histological images. CONCLUSIONS: Reflectance confocal microscopy was able to visualize PMN migration, accumulation, and degeneration over time in the used LTB4 model. The noninvasive character and the possibility to obtain multiple in vivo images from the same location over time make that RCM in combination with this model a useful tool to study the dynamics and function of PMN in inflammatory processes in the skin.

Combining tape stripping and non-invasive reflectance confocal microscopy : an in vivo model to study skin damage.

BACKGROUND: Evaluation of (immuno)histological and cell biological changes in damaged skin requires often an invasive skin biopsy, making in vivo models inappropriate to study skin damage. Reflectance confocal microscopy (RCM) might overcome this limitation. Therefore, we evaluated the use of a tape-stripping model in combination with RCM to provide morphological data on skin damage and recovery. METHODS: In 25 volunteers, a tape-stripping stimulus was applied. The skin was imaged with RCM during 1 week and 3 mm punch biopsies were obtained. RESULTS: Strong correlations between epidermal thickness determined by RCM and conventional histological measurements were found. RCM thickness measurements correlated well with epidermal proliferation. The 10× or 15× repeated tape-stripping resulted in skin damage similar to acute stripping. Mild repeated tape-stripping showed no skin damage. CONCLUSION: Overall, we demonstrated that non-invasive RCM in combination with tape-stripping could be used as model to obtain morphological and cell biological data on skin-material interactions.

Reflectance confocal microscopy: non-invasive distinction between actinic keratosis and squamous cell carcinoma.

BACKGROUND: Early recognition of squamous cell carcinoma (SCC) is difficult. Non-invasive reflectance confocal microscopic (RCM) imaging of the skin is a promising diagnostic technique. Although several RCM features for SCC and AK have been described, it is not determined whether RCM has the ability to distinguish between SCC and actinic keratosis (AK). OBJECTIVE: To determine in vivo reflectance confocal microscopic features that are specific for making a distinction between AK and SCC. METHODS: In 24 patients, 30 lesions clinically suspicious for AK or SCC were selected for RCM imaging. Following the imaging procedure, a 3 mm skin biopsy was obtained for confirmation of the histopathological diagnosis. Two observers evaluated the RCM images according to a literature based list of RCM features. The obtained data were evaluated by an univariate and forward multivariate logistic regression analysis, kappa analysis and independent T-test. RESULTS: The univariate logistic regression showed statistically significant odds ratios for several RCM features, including architectural disarray in the stratum granulosum, architectural disarray in the spinous layer and nest-like structures in the dermis. The forward multivariate logistic regression analysis showed that the combination of these features increased the ability to make the correct diagnosis AK and SCC non-invasively. The interobserver agreement between a starting and an experienced RCM observer ranged from poor to no agreement. CONCLUSION: This study revealed specific RCM features that can distinguish between AK and SCC, stimulating further prospective, large cohort research in this field. This will result in correct, efficient and adequate diagnosis and treatment of clinically difficult to distinguish AK and SCC lesions.

Prospective differentiation of clinically difficult to distinguish nodular basal cell carcinomas and intradermal nevi by non-invasive Reflectance Confocal Microscopy: a case series study.

BACKGROUND: Clinical differentiation between a nodular basal cell carcinoma (nBCC) and a benign intradermal nevus can be difficult. Even with additional dermoscopic evaluation, a correct diagnosis may be difficult. Currently, histopathological examination of a biopsy is the gold standard to differentiate between these lesions. However, this is an invasive technique and sampling errors can occur. In vivo Reflectance Confocal Microscopy (RCM) is a non-invasive technique to evaluate a skin lesion at a microscopic level. RCM features of nBCCs and intradermal nevi have been described in research setting. However, the use of RCM for prospective differentiation between difficult to diagnose nodules into nBCCs and intradermal nevi in clinical practice has not been demonstrated yet. OBJECTIVE: In this study, we aim to address a common clinical scenario; to differentiate clinically and dermoscopically difficult to distinguish nodules, into nBCCs and intradermal nevi by RCM. MATERIAL AND METHODS: Six patients with clinically and dermoscopically difficult to distinguish nodular skin lesions were evaluated by RCM to differentiate prospectively between nBCCs and intradermal nevi. In five out of six cases, a 3 mm punch biopsy was obtained to confirm the RCM diagnosis. RESULTS: Observed RCM features that allowed differentiation between nBCCs and intradermal nevi were the dermal-epidermal junction patterns, the appearance of the nests and the degree of vascularization. CONCLUSIONS: This case series study demonstrates the value of non-invasive in vivo RCM imaging in routine patient care, with respect to the prospective diagnosis of clinically difficult to distinguish nBCCs and intradermal nevi. Subsequently, biopsies of benign lesions in cosmetic areas could be avoided.

The effect of adalimumab on key drivers in the pathogenesis of psoriasis.

BACKGROUND: The use of recently introduced biologics targeting specific immune mechanisms has identified crucial steps in the pathogenesis of psoriasis. Studying the dynamics of changes of these target mechanisms in sequential skin biopsies during treatment with biologics may reveal potential biomarkers. Correlation between clinical parameters and the expression of specific genes during treatments may identify markers indicative of treatment response. OBJECTIVES: This observational open-label study aimed to provide an overview of important cell biological changes in lesional skin during treatment with adalimumab, and their relationship to clinical improvement. METHODS: Ten patients with moderate-to-severe plaque psoriasis were included and treated with adalimumab for 16 weeks. At baseline, and after 10 days and 16 weeks of treatment clinical scores were assessed and biopsies were taken to examine gene expression at the mRNA and protein level. RESULTS: The expression of marker genes for innate immunity, and epidermal differentiation and proliferation was rapidly restored to normal levels, whereas genes of the adaptive immune system showed a delayed decrease. The static and dynamic course of CD1a+ Langerhans cells and Ki67+ nuclei showed a significant strong correlation to the Psoriasis Area and Severity Index score. No correlation between interleukin-17 expression and clinical scores was found. CONCLUSIONS: The innate immune system is affected during adalimumab treatment well before the changes in the adaptive immune system become apparent. We may speculate that the addition of a treatment with an early effect on adaptive immunity to adalimumab may result in superior effectiveness compared with monotherapies.

Cutaneous application of leukotriene B4 as an in vivo model of psoriasis-like skin inflammation: an immunohistological study.

BACKGROUND: Research has revealed new insights into the pathogenesis of psoriasis, leading to new therapeutic options. So far the order of changes in the pathogenesis of psoriasis is unclear. The responses to cutaneous leukotriene B4 (LTB4) application have been studied in the past as an in vivo model for inflammation. The aim of the present study is to find out the order of changes of key steps in inflammation, which all have been shown to be involved in mature psoriatic lesions. OBJECTIVE: To study the dynamics of the consecutive stages of inflammation in challenged skin as a reflection of a psoriasis-like inflammatory response. METHODS: We examined the dynamics of epidermal growth control and the key representatives of the innate and acquired immune system during the first 72 h after challenging the skin by LTB4 application. RESULTS: Interleukin 17-positive (IL-17+) cells dominate the acute phase of inflammation, whereas T-Bet+ cells seem to increase gradually during the entire observation period. This indicates a more important role for IL-17 in the unstable phase of inflammation and a more prominent role for T-Bet+ cells within the chronic phase. CONCLUSION: The present model is highly reproducible and is useful in studying the dynamics of a psoriasis-like inflammation with respect to key components of immunity. It could provide a useful tool to study the immediate biological effects of new therapies like anti-IL-17 drugs on IL-17 production and effects on cutaneous inflammation and epidermal proliferation in vivo.

Balance of Treg vs. T-helper cells in the transition from symptomless to lesional psoriatic skin.

BACKGROUND: In the pathogenesis of psoriasis, proinflammatory T cells are strongly involved in the inflammatory process, where regulatory T-cell (Treg) function is impaired. OBJECTIVES: As effective Treg function is associated with a numerical balance between Treg and effector T cells, we wondered whether Treg/T-helper cell ratios may be associated with certain stages of the inflammatory process. We opted for the margin zone model as a dynamic approach. METHODS: From nine patients with chronic plaque psoriasis, 3-mm punch biopsies were obtained from the centre and margin of the lesion, perilesional skin and distant uninvolved skin. Skin biopsies of 10 healthy volunteers were included as a control. Samples were analysed using immunohistochemistry and immunofluorescence. RESULTS: In the transition from symptomless to lesional skin, a significant increase of CD3+, CD4+ and Foxp3+ cells was found. In seven of nine patients the ratio of Treg (Foxp3+) vs. CD4+ T cells was higher in the distant uninvolved skin than in the perilesional and lesional skin. Interestingly, the Foxp3/CD4 ratio in the distant uninvolved skin was even higher than in the skin of healthy controls. Notably, we found that most of the interleukin (IL)-17 expression was not related to CD4+ cells, but to mast cells. CONCLUSIONS: The relatively high Foxp3/CD4 ratio in symptomless skin of patients with psoriasis suggests an active immune controlling mechanism distant from the psoriatic plaque. In the margin and centre of the plaque the ratio appears skewed towards effector cells associated with inflammation. IL-17, an important driver of the psoriatic process, is mostly related to mast cells, and only sporadically to T cells.

High discordance between punch biopsy and excision in establishing basal cell carcinoma subtype: analysis of 500 cases.

BACKGROUND: Basal cell carcinoma (BCC) is the most frequently occurring cancer in humans. Worldwide incidences rise about 10% each year, increasing the burden on dermatologists, general practitioners and pathologists as well as increasing costs for the health care system. Increasingly non-surgical treatment options are used in the treatment of BCC, without histological confirmation of BCC subtype, potentially resulting in under-treatment. OBJECTIVE: We evaluated the diagnostic accuracy of a punch biopsy for the BCC histological subytpe in a primary BCC and the prevalence of biopsy-based under-diagnosis of aggressive subtypes. Accuracy of a punch biopsy was defined as concordance of the diagnosis of subtype of BCC at punch biopsy and excision. METHODS: A retrospective chart-review was performed of primary BCC, which were proven by punch biopsy and subsequently treated by excision. The first 100 consecutive BCCs per year during the years 2004-2009 were included, yielding a total of 500 evaluated BCCs. RESULTS: The overall accuracy of punch biopsy for BCC subtype at excision was 69%, in single-type BCC 83% (n = 343) and in mixed-type BCC 37% (n = 157). Accuracy varied substantially according to BCC subtype, being highest in the superficial subtype (84%) and subsequently in infiltrative (69%), nodular (63%) and micronodular subtype (38%). In 11% of all cases, an unsuspected more aggressive subtype was present. CONCLUSION: Punch biopsy has a high accuracy in single-type BCCs and a considerably lower accuracy in mixed-type BCCs for establishing BCC subtype compared to excision. The presence of an unsuspected aggressive subtype could explain therapy failure of non-surgical treatments like imiquimod or photodynamic therapy.

The potential of the skin as a readout system to test artificial turf systems: clinical and immunohistological effects of a sliding on natural grass and artificial turf.

The purpose of this study was to investigate the interaction of skin with natural grass and artificial turf at clinical, histological and immunohistochemical level. Therefore, 14 male volunteers performed slidings on dry natural grass, wet natural grass and artificial turf. Directly and 24 h after the slidings, a clinical picture and a 3-mm punch biopsy of the lesion were taken. Paraffin sections (6 µm) were hematoxylin-eosin stained. Immunohistochemistry was performed for CD3, hBD-2, K16, K10, Ki67 and HSP70. Clinically, a sliding performed on artificial turf caused less erythema but more abrasion compared to natural grass. At histological level, artificial turf or dry natural grass damaged the stratum corneum the most. Directly after the sliding, CD3, hBD-2, K16, K10, Ki67 and HSP70 expression was normal. 24 h after a sliding on artificial turf or dry natural grass, an increase of K16, hBD-2 and HSP70 expression was observed. In this pilot study it was not possible to clearly distinguish between skin damage induced by a sliding on artificial turf and natural grass. However, small differences at clinical and histological level seem to exist. This demonstrates the potential of the skin as readout system to evaluate artificial turf systems and mechanical skin damage.

Reflectance confocal microscopy: an effective tool for monitoring ultraviolet B phototherapy in psoriasis.

BACKGROUND: In vivo reflectance confocal microscopy (RCM) is a novel, noninvasive imaging technique which enables imaging of skin at a cellular resolution comparable to conventional microscopy. OBJECTIVES: We performed a pilot study to evaluate RCM as a noninvasive tool for monitoring ultraviolet (UV) B phototherapy in psoriasis. METHODS: In six patients with psoriasis, lesional and nonlesional skin was selected for RCM imaging using a standardized protocol. Well-known histological features of psoriasis were visualized: parakeratosis, acanthosis, agranulosis, papillomatosis, presence of epidermal inflammatory cells, increased number of papillary capillaries and increased capillary blood flow. RCM imaging was performed before the first irradiation with UVB phototherapy, after nine irradiations, at clearance and 12 weeks after clearance. In four patients, 4-mm punch biopsies were obtained and stained with haematoxylin-eosin. Additionally, immunohistochemical staining was performed with monoclonal antibodies specific for CD31, CD3, filaggrin, K16, Ki67 and CD1a for correlation to RCM images. RESULTS: There was a high correlation between clinical, RCM and histological features. Normalization of RCM and histological features corresponded highly to clinical improvement of psoriasis. CONCLUSIONS: This study is the first to establish the use of RCM as an effective tool for noninvasive monitoring of UVB phototherapy in patients with psoriasis. Potentially, RCM could be used in many other skin diseases for monitoring therapeutic response on a cellular level in a clinical or research setting.

Efficacy of blue light vs. red light in the treatment of psoriasis: a double-blind, randomized comparative study.

BACKGROUND: Protoporphyrin IX is present in psoriatic skin without the preceding application of aminolevulinic acid. Therefore, endogenous photosensitizers in psoriasis are a potential target for photodynamic treatment with high-dose visible light. OBJECTIVES: In the present pilot study, treatment with high-dose blue and red light in psoriasis were analysed with respect to clinical improvement and potential side-effects. METHODS: In 20 patients, two stable psoriatic plaques were treated with either blue or red light, three times weekly for four consecutive weeks. To remove scaling that could potentially interfere with penetration of the light into the skin, daily application of 10% salicylic acid in petrolatum was started at the screening visit and continued until the end of the study. RESULTS: Clinical improvement was seen after treatment with blue as well as after treatment with red light. With respect to scaling and induration, no major differences between both light sources were seen. Improvement of erythema, however, continued in blue light irradiated plaques throughout the whole study period, whereas after red light no significant improvement was seen after six illuminations. CONCLUSIONS: The clinical improvement of psoriasis, with respect to erythema, in particular after blue light and to a lesser extent after red light indicates that visible light treatment could represent a treatment option for psoriasis.