Dermoscopic features of plaque psoriasis and lichen planus: new observations

Abstract

Background: Dermoscopic features of common inflammatory dermatoses are not well studied and previous reports on this topic are limited to the search of vascular features (capillaroscopy).

Objective: Dermoscopic features of psoriasis and lichen planus (LP) are investigated to determine both vascular and nonvascular features of these two dermatoses.

Patients and methods: Dermoscopic images of 25 patients with LP and 20 patients with plaque psoriasis (PP) were evaluated. Findings were statistically analyzed including the reproducibility of scoring (Cohen's kappa statistics).

Results: Our observations clearly showed that the evaluation of both vascular and nonvascular findings improved the surface microscopy of these diseases. A vascular feature (homogeneous red globules) was the most significant dermoscopic finding in the PP dermoscopic pattern (20/20, 100%; p < 0.001). A nonvascular feature (whitish striae) was the most significant dermoscopic feature in the LP pattern (23/25, 92%; p < 0.001). Dermoscopic features of LP also included gray-blue dots, comedo, milium-like cysts, and vascular structures (red lines). The intraobserver and interobserver reproducibility of scoring was very high (k value, 0.9).

Conclusion: Our study shows for the first time that the efficacy of surface microscopy of common inflammatory dermatoses may be improved by investigating both vascular and nonvascular findings and its practicability in daily practice by using the dermoscope. Although dermoscopy does not provide clear additional help in the clinical differentiation between typical PP and LP, it could be helpful in patients with darker skin and for teaching settings.