Dermoscopy of Necrobiosis Lipoidica and Granuloma Annulare

Abstract

Background: Dermoscopy is traditionally used for the diagnosis of skin tumors, but it has also gained increasing interest as an adjunct in the clinical diagnosis of inflammatory skin diseases. Objective: To evaluate the dermoscopic patterns of necrobiosis lipoidica (NL) and granuloma annulare (GA) and to compare these findings with other granulomatous skin disorders. Methods: This is a retrospective analysis of patient data and clinical and dermoscopic images of histopathologically diagnosed cases of NL and GA. Results: A total of 24 cases, including 12 cases of NL and 12 cases of GA, were evaluated. In all cases of NL, dermoscopy revealed evident, sharply focused, elongated and serpentine telangiectasias, which were typically located over a whitish, structureless background. In contrast, all cases of GA were dermoscopically typified by peripheral, structureless orange-reddish borders, which were associated in 5 cases with isolated, unfocussed small vessels. Conclusion: Our study suggests that NL and GA reveal different dermoscopic patterns, which may aid the correct diagnosis. In addition, the dermoscopic patterns of NL and GA appear to differ from other forms of granulomatous diseases.