Classifying Eschar Morphologies: Enhancing Early Diagnosis of Scrub Typhus.

Background: Scrub typhus, a rickettsial disease caused by Orientia tsutsugamushi, presents with diverse clinical manifestations, with eschar formation being a key diagnostic feature.

Methods: In this retrospective study, we analyzed 81 confirmed cases at Jeonbuk National University Hospital between January 2018 and December 2020 to systematically categorize eschar morphology and distribution.

Results: Eschars were classified into five types based on their morphology: erythematous macules (2.5%), vesicular (4.9%), erosive/ulcerative (13.6%), crusted (74.1%), and sclerotic (4.9%). The most common site was the anterior body (44.4%) followed by the inguinal area (18.5%). Notably, 25.9% of cases exhibited atypical eschars lacking classical black crust, complicating the diagnosis. Eschar type distribution differed significantly between covered and exposed body areas (P = 0.038), probably due to physiological differences in skin regions or the timing of eschar detection.

Conclusion: These findings highlight the need for comprehensive skin examinations and increased awareness of atypical eschars to enhance the diagnostic accuracy and improve the clinical outcomes of scrub typhus.