Progress in the application of reflectance confocal microscopy in dermatology

Vitiligo Treated with Combined Piperine-Based Topical Treatment and Narrowband Ultraviolet B Therapy: Follow-Up with Reflectance Confocal Microscopy

BACKGROUND

Reflectance confocal microscopy (RCM) has a defined in vivo morphology of vitiligo and re-pigmentation. Combination therapies seem more effective than monotherapies.

OBJECTIVE

We aim to describe the clinical and RCM features of re-pigmentation with combined narrowband ultraviolet B (NB-UVB) and piperine-based topical treatment in localized vitiligo.

METHODS

Eight patients enrolled at a single center received combined treatment: topical treatment was applied twice daily + NB-UVB twice weekly for 2 × 2-month periods. Clinical changes were analyzed by the Vitiligo Noticeability Scale (VNS) and percentage of re-pigmentation. The evaluator agreement was assessed. Predefined RCM features had the presence/absence of (i) blood vessels, (ii) dendritic cells, and the quantity of (i) an irregular honeycombed pattern and (ii) non-pigmented papillae. Clinical and RCM monitoring was performed at the baseline, 2, 3, 5, and 7 months.

RESULTS

Macules were "slightly less noticeable" with 25-50% re-pigmentation. Irregular honeycomb patterns and non-pigmented papillae were significantly less frequently observed, and in less extended areas (T1 vs. T2, p = 0.039; T0 vs. T1, p = 0.005 and T2 vs. T4, p = 0.033). Dendritic cells and blood vessels improved, with significant changes in blood vessels (T1 vs. T2, p = 0.005 and T3 vs. T4, p = 0.008).

CONCLUSIONS

RCM confirms the morphological changes induced by combined treatment for localized vitiligo.

Clinical factors associated with remission of obese acanthosis nigricans after laparoscopic sleeve gastrectomy: a prospective cohort study

BACKGROUND

Acanthosis nigricans (AN) involves skin hyperpigmentation in body folds and creases. Obesity-associated AN (OB_AN) is the most common type of AN. The skin condition of obese patients with AN can be improved through bariatric surgery, such as laparoscopic sleeve gastrectomy (LSG), after weight loss. However, the contributing factors to the remission of AN after surgery are still not fully determined. The authors aimed to assess the metabolic and pathological factors associated with remission of AN following LSG in obese individuals.

METHODS

The study included 319 obese patients who underwent LSG at our hospital. The subjects were divided into obesity (OB) only (OB, n =178) or OB with AN (OB_AN, n =141) groups. The basic clinical and metabolic indices and the dermatological features via reflectance confocal microscopy and histology were collected from patients prior to and after LSG.

RESULTS

OB_AN patients had higher fasting plasma glucose, homeostatic model assessment for insulin resistance, and testosterone levels than OB patients. LSG could significantly improve the biochemical and histopathological features of OB_AN patients. The remissive rate of OB_AN patients was about 86.5% (122 out of 141) after surgery. The remission of OB_AN skin lesions was positively correlated with testosterone levels ( P <0.01). In addition, there was a significant positive correlation between changes in AN scores and epidermal thickness and skin pigmentation scores after surgery ( P <0.01).

CONCLUSION

The remissive rate of OB_AN after LSG is associated with improved testosterone levels and reduced epidermal thickness and skin pigmentation levels.

Unveiling the mystery of Riehl's melanosis: An update from pathogenesis, diagnosis to treatment

Riehl's melanosis is a hyperpigmentation disorder that has a significant psychological and social impact on individuals. In the past 10 years, new categories have been developed, raising questions about how to classify Riehl's melanosis. The mechanism of this disease remains unclear, although the type IV hypersensitivity response caused by allergic sensitization, as well as genetic, ultraviolet radiation, and autoimmune factors, is to blame. Clinical manifestation, dermoscopy, reflectance confocal microscopy, patch/photopatch testing, histopathology, and a novel multimodality skin imaging system have been used for the diagnosis. A variety of therapies including topical skin-lightening agents, oral tranexamic acid, glycyrrhizin compound, chemical peels, and lasers and light therapies (intense pulsed light, 1064-nm Q-Switched Nd: YAG laser, 755-nm PicoWay laser, nonablative 1927-nm fractional thulium fiber laser, new pulsed-type microneedling radiofrequency), with improved effectiveness. The latest findings on possible biomarkers and their relationship to other autoimmune diseases were also summarized.

Observation and density estimation of a large number of skin capillaries using wide-field portable video capillaroscopy and semantic segmentation

Significance

Skin capillaries are non-invasively observable; their structure and blood flow can reflect tissue and systemic conditions. Quantitative analysis of video-capillaroscopy images yields novel diagnostic methods. Because the capillary structure is heterogeneous, analyzing more capillaries can increase the evaluation reliability.

Aim

We developed a system that can observe and quantify numerous capillaries and verified the performance on human skin.

Approach

We developed a portable video-capillaroscope with a spatial resolution higher than 3.5    μ m and a wide field of view (7.4    mm × 5.5    mm ) and a method to evaluate capillary numbers and areas using U-Net. The model was trained and tested with 22 and 11 cropped images (2.4    mm × 1.9    mm ) obtained from 11 participants, respectively. They were then applied to the 7.2    mm × 5.3    mm images from four participants. Segmentation results were compared to ground-truth at the pixel level and capillary-region level.

Results

Over 1000 capillaries were simultaneously observed using the proposed system. Although pixel-level segmentation performance was low [intersection over union (IoU) = 24.5%], the number and area could be estimated. These values differed among four participants and seven sites, and they changed after skin barrier destruction.

Conclusions

The proposed system allows for observing and quantifying numerous skin capillaries simultaneously, suggesting its potential for evaluating tissue and systemic conditions.

The Role of Reflectance Confocal Microscopy in the Diagnosis and Therapeutic Evaluation of Rare Disease Eosinophilic Pustular Folliculitis

Eosinophilic pustular folliculitis (EPF) is a rare skin disease for which the gold standard of diagnosis relies on the invasive examination of pathological tissue sections. However, due to its invasive nature, many patients tend to refuse this diagnostic test. In such situations, reflectance confocal microscopy (RCM) can be a valuable diagnosis tool. Reflectance confocal microscopy (RCM) can accurately identify the specific structures for biopsy and provide objective imaging data to evaluate clinical symptoms following treatment. Therefore, we present a case report demonstrating the utility of RCM in diagnosing and assessing the treatment of the rare disease EPF for reference.