Reflectance Confocal Microscopy Features of Seborrheic Dermatitis for Plaque Psoriasis Differentiation

Background: Plaque psoriasis (PP) and seborrheic dermatitis (SD) are chronic inflammatory skin diseases with similar clinical and pathological features. Differential diagnosis can be difficult, especially when particular skin areas of the face are involved. Reflectance confocal microscopy (RCM) has been demonstrated to be useful for ‘real-time' diagnosis of skin inflammatory diseases. Objective: To define distinctive confocal criteria of SD and to evaluate the usefulness of this technique for noninvasive differential diagnosis with PP. Methods: A total of 40 patients affected by PP and 19 patients by SD involving the face were recruited and subjected to RCM evaluation. Univariate and adjusted odds ratios were calculated. Discriminant functions were used to plot ROC curves. Results: The results disclosed specific patterns for SD and PP. The following distinctive confocal features for SD have been identified: spongiosis, dermal inflammation and horizontal orientation of dilated blood vessels. Conclusion: SD has a specific and easily recognizable confocal pattern supporting clinical differentiation with PP.