Preliminary evaluation of benign vascular lesions using in vivo reflectance confocal microscopy.

BACKGROUND: Reflectance confocal microscopy (RCM) is a novel noninvasive imaging technique for in vivo evaluation of cutaneous lesions at near-histologic resolution. The applicability of RCM for various neoplastic and inflammatory skin diseases has been shown, but a descriptive evaluation of different vascular lesions has not yet been performed. OBJECTIVES: To define specific RCM criteria for congenital and acquired vascular lesions and to determine whether these criteria may assist in their differential diagnosis. MATERIALS AND METHODS: Seven patients with a clinical diagnosis of vascular lesion, including spider angioma, venous lake, cherry angioma, pyogenic granuloma, port wine stain, angiokeratoma, and lymphangioma, participated in this study. Skin sites were systematically analyzed using RCM, and biopsy was obtained for clinically indeterminate lesions. RESULTS: For each entity, characteristic RCM criteria could be identified and selected parameters correlated well to established histopathologic findings. The most relevant criteria included the diameter of the vessels and degree of vascular tortuosity or dilation. Additional findings such as flow velocity, inflammation, and disruption of the epidermal architecture could be documented. CONCLUSION: The findings of this preliminary evaluation indicate that RCM may aid in the noninvasive characterization of inflammatory, proliferative, and ectatic vascular malformations in vivo.

Effects of a 1,450 nm diode laser on facial sebum excretion.

BACKGROUND AND OBJECTIVE: Laser therapy with a 1,450 nm diode laser is a clinically effective treatment for acne vulgaris, although the mechanism of action is unknown. To investigate this, we conducted a small, prospective, controlled clinical trial to assess this laser's effects on the facial sebum excretion rate (SER). MATERIALS AND METHODS: Fourteen healthy volunteers without active acne were enrolled in this study and received three laser treatments on test areas of the nose and forehead. Nine subjects completed the treatment regimen and were available for follow-up. SER was measured with Sebumeter prior to the first treatment, and at 1 week and 1 month after the third treatment. Photographs were taken and subjective assessment of skin oiliness and pore size determined by questionnaires at 1 month follow-up. RESULTS: No significant reduction in SER was observed comparing treated with control on all treatment sites (P>0.05) on the nose. Reduction in the absolute SER was observed for both test and control sites on the forehead, reaching significance on the treatment site (P = 0.04) and marginal significance on the control site (P = 0.08). CONCLUSION: While our study was designed to detect only large changes in SER, we conclude that three 1,450 nm laser treatment sessions did not cause marked changes in SER compared to the control (i.e., >44%). Thus, major destruction of sebaceous glands as a result of this treatment is unlikely. However, reduced sebum production was observed on both treatment and control sides at 1 month. Therefore alternative mechanisms should also be considered to explain the clinical efficacy of this treatment for acne vulgaris.

Multiple clustered dermatofibroma with overlying sebaceous hyperplasia.

Multiple clustered dermatofibroma is a very rare clinical variant of the dermatofibroma, and sebaceous differentiation overlying dermatofibromas is also unusual. We report the first case of a multiple clustered dermatofibroma with overlying sebaceous hyperplasia.

Clinical applicability of in vivo fluorescence confocal microscopy for noninvasive diagnosis and therapeutic monitoring of nonmelanoma skin cancer.

Excisional biopsies and routine histology remains the gold standard for the histomorphologic evaluation of normal and diseased skin. However, there is increasing interest in the development of noninvasive optical technologies for evaluation, diagnosis, and monitoring of skin disease in vivo. Fluorescent confocal microscopy is an innovative optical technology that has previously been used for morphologic evaluation of live human tissue. We evaluate the clinical applicability of a fluorescent confocal laser scanning microscope (FLSM) for a systematic evaluation of normal and diseased skin in vivo and in correlation with routine histology. A total of 40 patients were recruited to participate in the study. Skin sites of 10 participants with no prior history of skin disease served as controls and to evaluate topographic variations of normal skin in vivo. Thirty patients with a suspected diagnosis of nonmelanoma skin cancer were evaluated, whereby FLSM features of actinic keratoses (AK) and basal cell carcinoma (BCC) were recorded in an observational analysis. Selected BCCs were monitored for their skin response to topical therapy using Imiquimod as an immune-response modifier. A commercially available fluorescence microscope (OptiScan Ltd., Melbourne, Australia) was used to carry out all FLSM evaluations. Common FLSM features to AK and BCC included nuclear pleomorphism at the level of the granular and spinous layer and increased vascularity in the superficial dermal compartment. Even though the presence of superficial disruption and mere atypia of epidermal keratinocytes was more indicative of AK, the nesting of atypical basal cells, increased blood vessel tortuosity, and nuclear polarization were more typical for BCC. All diagnoses were confirmed by histology. FLSM allowed a monitoring of the local immune response following therapy with Imiquimod and demonstrated a continuous normalization of diseased skin on repeated evaluations over time. This study illustrates potential applications of FLSM in clinical dermatology for the evaluation of dynamic skin conditions and monitoring of cutaneous response to noninvasive therapies. The findings are of preliminary nature and warrant further investigations in the future.

Clinical evaluation of a 1,450-nm diode laser as adjunctive treatment for refractory facial acne vulgaris.

BACKGROUND: Despite aggressive multitreatment medical acne regimens, many patients demonstrate modest benefit. The 1,450-nm diode laser has been shown to improve acne in a study setting. OBJECTIVE: Herein we evaluate the use of this laser as an adjunctive tool in the management of refractory facial acne vulgaris. MATERIALS AND METHODS: Thirteen patients were treated. Lesion counts, clinical evaluation, and digital photography were performed at baseline and at all follow-up visits. Patients received an average of three treatments. Acne severity index and patient satisfaction were assessed. Patients continued their medical acne regimen where applicable. RESULTS Mean total lesion and inflammatory lesion counts decreased from 66 +/- 14 and 23 +/- 5 at baseline to 34 +/- 12.9 and 14 +/- 7 after three treatments (p<.05). Side effects were mild, including erythema lasting up to 24 hours. CONCLUSION: The 1,450-nm diode laser provides moderate improvement of refractory acne vulgaris. Our findings support the use of this device as an adjunctive treatment for acne management.

Clinical applicability of in vivo reflectance confocal microscopy for the diagnosis of actinic keratoses.

BACKGROUND: In vivo reflectance confocal microscopy (RCM) has been used for evaluation of the morphologic features of nonmelanoma skin cancer. The application of RCM for diagnosis of basal cell carcinoma has been reported; however, the evaluation of actinic keratoses (AKs) has only been the subject of preliminary studies. STUDY GOAL: The goal of this study was to evaluate the applicability of RCM in the diagnosis of AK in correlation with routine histology. MATERIALS AND METHODS: Forty-four Caucasians with a minimum of one AK participated in this study. Evaluation consisted of clinical examination, RCM, and routine histology, including a total of 46 AKs in the final analysis. Ten normal skin sites served as controls. RCM features of AK included parakeratosis, architectural disarray, and keratinocyte pleomorphism. Following blinded evaluations, sensitivity/specificity, kappa analysis, and Spearman's correlation were performed on all parameters. RESULTS: Sensitivity/specificity values of RCM features ranged from 80% to 98.6%. The presence of architectural disarray and cellular pleomorphism appeared to be the best predictor of AK. CONCLUSION: In summary, RCM may be a promising technology for the noninvasive detection of AK and as adjunct tool to clinical diagnosis and monitoring. However, the preliminary nature of this study warrants further investigations.

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.

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.

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.

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.

In vivo assessment of pigmentary and vascular compartments changes in UVA exposed skin by reflectance-mode confocal microscopy.

Exposure of the skin to ultraviolet A (UVA) results in various biological responses, skin-colour changes being among the major ones. Although intense research has been performed on UVA-induced pigmentation and vascular changes, the process of skin-colour changes after UVA irradiation remains unclear. For a better understanding of the UVA tanning mechanism, we here performed a human study in 27 healthy volunteers with skin phototype (SPT) II to VI. After a single UVA exposure to inner forearm, the skin sites were imaged using reflectance-mode confocal microscopy (RCM), for analysis of melanin and vascular changes. Punch biopsies were also taken from the UVA-exposed or non-exposed sites for histological examination. Skin sections were stained with Fontana-Masson and evaluated by a sensitive tyrosinase assay for comparison with RCM images. Furthermore, the effect of blood flow on skin-colour changes was evaluated visually after administration of an intradermal anesthesia of lidocaine with or without epinephrine. Our RCM analysis showed dendritic melanocytes and a different melanin distribution in the epidermal layer, clearly visible 1 week after the UVA exposure in subjects of SPT V which were supported by histological examination. However, no melanin distribution pattern changes were apparent immediately after the exposure, while RCM images showed accelerated capillary flow patterns. The restriction of this UVA induced-accelerated blood flow by epinephrine inhibited partially or completely the immediate pigment darkening and delayed tanning. These in vivo studies confirmed that vascular change is an important factor for the development of the immediate pigment darkening and delayed tanning.

Treating vascular lesions.

The treatment of acquired vascular lesions is one of the most commonly requested and performed cutaneous laser procedures. Furthermore, every year, 40,000 children are born in the United States each with congenital vascular lesions and malformations. Laser treatment of vascular lesion is based on the principle of selective photothermolysis, conceived in the 1980s. A variety of different lasers and light sources have since been used in the treatment of vascular lesions: lasers with wavelengths between green and yellow, near infrared lasers, and broadband light sources. Despite limitations, this remains the treatment of choice today. This publication addresses acquired and congenital vascular lesions as different entities and proposes a separation of vascular lesions into those that can easily be treated from those where clearance is difficult. Different treatment modalities and the various endpoints of individual vascular lesions will be discussed.

Utilizing fractional resurfacing in the treatment of therapy-resistant melasma.

BACKGROUND: Multiple treatment modalities have been employed for the management of melasma with minimal to no success. OBJECTIVE: We propose fractional resurfacing as a new treatment modality for melasma. METHODS: A 31-year-old Caucasian female with facial epidermal and dermal melasma, resistant to multiple courses of topical therapies, was treated with two sessions of full-face fractional resurfacing (Fraxel(TM) Laser; Reliant technologies, San Diego, CA), separated by a three-week interval. Clinical improvement was assessed by Wood's Lamp examination as well as parallel and cross-polarized comparative photography at baseline and 6 months later. RESULTS: Marked reduction in epidermal and dermal facial pigmentation was observed at the six-month follow-up visit. CONCLUSION: Fractional resurfacing may prove to be an effective and safe treatment modality for lightening of the epidermal and dermal pigmentation of melasma. Further studies with long-term follow-up periods and multiple patients with diverse skin phototypes and different variants of melasma are warranted.

Comparative study of three intramuscular anaesthetic combinations (medetomidine/ketamine, medetomidine/fentanyl/midazolam and xylazine/ketamine) in rabbits.

OBJECTIVE: To compare the quality of surgical anaesthesia and cardiorespiratory effects of three intramuscular (IM) anaesthetic combinations in rabbits. STUDY DESIGN: Prospective randomized cross-over experimental study. ANIMALS: Nineteen adult female chinchilla mixed-bred rabbits weighing 3.9 +/- 0.8 kg. METHODS: Rabbits were given one of three IM anaesthetic combinations: 0.25 mg kg(-1) medetomidine and 35.0 mg kg(-1) ketamine (M-K), 0.20 mg kg(-1) medetomidine and 0.02 mg kg(-1) fentanyl and 1.0 mg kg(-1) midazolam (M-F-Mz) and 4.0 mg kg(-1) xylazine and 50 mg kg(-1) ketamine (X-K). The effects of anaesthesia on nociceptive reflexes, circulatory and respiratory function were recorded. Statistical analyses involved repeated measures anova with paired Student's t-test applied post hoc. P-values <0.05 were considered as significant. RESULTS: Reflex loss was most rapid and complete in M-K recipients, whereas animals receiving M-F-Mz showed the longest tolerance of endotracheal intubation (78.1 +/- 36.5 minutes). Loss of righting reflex was significantly most rapid (p < 0.05) in the X-K group (114.7 +/- 24.0 minutes). Surgical anaesthesia was achieved in 16 of 19 animals receiving M-K, in 14 animals receiving M-F-Mz, and in seven animals with X-K, but only for a short period (7.1 +/- 11.6 minutes). This was significantly (p < 0.001) shorter than with M-K (38.7 +/- 30.0 minutes) and M-F-Mz (31.6 +/- 26.6 minutes). Heart rates were greatest in X-K recipients; lowest HR were seen in animals receiving M-F-Mz. Mean arterial blood pressure was significantly higher (about 88 mmHg) during the first hour in the M-K group. During recovery, the greatest hypotension was encountered in the X-K group; minimum values were 53 +/- 12 mmHg. Six of 19 animals in the M-F-Mz group showed a short period of apnoea (30 seconds) immediately after endotracheal intubation. Respiratory frequency was significantly lower in this group (p < 0.001). Highest values for arterial carbon dioxide partial pressures (PaCO(2)) (6.90 +/- 0.87 kPa; 52.5 +/- 6.5 mmHg) occurred after induction of anaesthesia in group M-F-Mz animals. There was a marked decrease in PaO(2) in all three groups (the minimum value 5.28 +/- 0.65 kPa [39.7 +/- 4.9 mmHg] was observed with M-K immediately after injection). Arterial PO(2) was between 26.0 and 43.0 kPa (196 and 324 mmHg) in all groups during O(2) delivery and decreased - but not <7.98 kPa - on its withdrawal. Immediately after drug injection, pH(a) values fell in all groups, with lowest values after 30 minutes (7.23 +/- 0.03 with M-K, 7.28 +/- 0.05 with M-F-Mz, and 7.36 +/- 0.04 with X-K). The X-K animals showed significantly (p < 0.001) higher pH values than medetomidine recipients. During 1 hour of anaesthesia pH values in the medetomidine groups remained below those of the X-K group. CONCLUSIONS: Surgical anaesthesia was induced in most animals receiving medetomidine-based combinations. Arterial blood pressure was maintained at baseline values for about 1 hour after M-K. Transient apnoea occurred with M-F-Mz and mandates respiratory function monitoring. Oxygen enrichment of inspired gases is necessary with all three combinations. Endotracheal intubation is essential in rabbits receiving M-F-Mz. CLINICAL RELEVANCE: The quality of surgical anaesthesia was greatest with M-K. All combinations allowed recoveries of similar duration. It is theoretically possible to antagonize each component of the M-F-Mz combination.