Dermoscopic Findings and the Clinicopathologic Correlation of Pigmented Purpuric Dermatosis: A Retrospective Review of 60 Cases

BACKGROUND: Pigmented purpuric dermatosis (PPD) is known as a chronic recurrent eruption which usually presents with petechiae and pigmented macules on the lower extremities. Dermoscopy is a noninvasive diagnostic tool in identifying pigmented and vascular lesions, which can also be beneficial in the evaluation of PPD. OBJECTIVE: We aimed to analyze the common dermoscopic characteristics of PPD, and correlate those findings with the histopathologic features. Additionally, dermoscopic and pathological findings in this study population were compared with other similar studies from the literature review. METHODS: A retrospective analysis was performed using data of 60 patients who were diagnosed as PPD by skin biopsy and had dermoscopic examination. The pathologic analysis was performed by categorizing the pattern into lichenoid, perivascular, interface, and spongiotic subtype, and the dermoscopic assessment was performed by the three authors independently. RESULTS: In dermoscopy, 96.7% of the patients showed red globules and dots, followed by brownish patch, coppery-red pigmentation, and annular comma-like vessels. The pathologic pattern analysis revealed statistically significant association of lichenoid pattern with coppery red pigmentation, perivascular pattern with annular/comma-like vessels, and spongiosis pattern with reticular pigmented network and linear vessels. The interrater similarity test showed total kappa value of 0.811 which referred to “very good”. CONCLUSION: In this study, the prevalence of dermoscopic features in Asian PPD patients was identified, which was similar with previous studies. The dermoscopic-pathologic correlation was found in four dermoscopic features. We suggest that dermoscopic examination is helpful in clinical diagnosis and pathological prediction of PPD.