Ultraviolet-Induced Fluorescence Dermatoscopy (UVFD) features in Porokeratosis: Findings from a Multicenter Retrospective Study

Introduction: Porokeratosis is a group of keratinization disorders characterized by the histopathological presence of the cornoid lamella, a hallmark feature across all subtypes. The clinical diagnosis of porokeratosis can be challenging due to its similarity to other dermatological conditions. While polarized light dermatoscopy (PLD) enhances diagnostic accuracy, certain features remain difficult to identify. Ultraviolet-induced fluorescence dermatoscopy (UVFD) is a novel imaging technique that may improve the visualization of porokeratosis features, particularly the peripheral keratin rim. Objectives: This study aimed to assess the diagnostic utility of UVFD compared with PLD in identifying the dermatoscopic features of porokeratosis. Methods: In this retrospective study, dermatologists from five institutions in Chile, Brazil, Poland, and the United States contributed with dermatoscopic images of porokeratosis cases. Both PLD and UVFD images were obtained for each lesion. Two independent investigators evaluated each lesion in PLD and UVFD for the presence of peripheral keratin rim, rim continuity, central scaling, follicular plugs, vascular structures, and photodamaged surrounding skin. A third investigator reviewed discrepancies. Frequencies and means were calculated. McNemar’s chi-square was used for comparison. Results: A total of 136 lesions from 35 patients with biopsy-proven porokeratosis were analyzed. UVFD significantly improved the visualization of the peripheral keratin rim (95.6% vs. 66.2% in PLD; P<0.001) and increased identification rates for central scaling, follicular plugs, and interrupted rims. PLD remained superior for detecting vascular structures(P<0.001). Conclusions: UVFD enhances the visualization of key dermatoscopic features of porokeratosis, particularly the peripheral keratin rim and other keratin-related structures.