Classifying Eschar Morphologies: Enhancing Early Diagnosis of Scrub Typhus

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

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.

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.

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.