Abstract
Inflammatory skin diseases are common and often difficult to differentiate. Ex vivo confocal laser scanning microscopy (EVCM) offers a rapid and promising approach. This study aimed to assess the diagnostic utility of EVCM in differentiating inflammatory dermatoses, particularly eczema, psoriasis and lichen planus, by comparing its performance with gold standard histopathology. Tissue samples of 110 patients presenting with inflammatory skin conditions were subjected to both EVCM and conventional histopathology. EVCM images were analysed by three blinded observers, with varying knowledge in histopathology and EVCM, utilising pattern analysis based on Ackermann's classification and single-cell analysis focusing on neutrophil (neutrophils) and eosinophil (eosinophils) granulocytes. Sensitivity and specificity were calculated using contingency tables. We used Cohen's Kappa coefficient and Firth's logistic regression models to evaluate the correlations between disease-associated histopathological features observed via EVCM and histopathology, as well as their impact on accurate histopathological diagnoses. Our findings demonstrate that EVCM provides rapid and insightful visualisation of characteristic features associated with inflammatory dermatological diseases. Diagnostic accuracy varied based on observer experience. The specialist proficient in both EVCM and histopathology achieved the highest accuracy rates for correctly diagnosing lichen planus (97.27%), psoriasis (95.45%) and eczema (92.73%). In conclusion EVCM emerges as a promising adjunct to histopathology, offering a swift and meaningful visualisation of inflammatory disease features. The integration of EVCM could significantly contribute to expediting diagnostic workflows and facilitating prompt, targeted therapeutic interventions. Further research and validation are warranted to establish EVCM's role in routine clinical practice.