Prevalence Rate and Distribution of Eschar in Patients with Scrub Typhus

Eschar is used to establish the clinical diagnosis of scrub typhus. To identify the prevalence of eschar and its location in scrub typhus, we reviewed globally published peer-reviewed articles. We conducted a systematic literature review, using publications extracted from PubMed from January 1943 to August 31, 2019 with the keywords “scrub typhus” or “tsutsugamushi.” We collected articles associated with eschar prevalence and distribution in scrub typhus infection and reported on the body locations of eschar. A total of 458 articles containing information on the prevalence, geographical distribution, and body distribution of eschar were used for this review. The overall prevalence rate of eschar was 58.0% with the greatest prevalence in East Asia (78.7%) followed by Oceania (52.2%), Southeast Asia (41.4%), and then the lowest in South Asia (32.8%). The frequency of eschar distribution was highest in the inguinal area (28.5%), followed by the anterior area (28.0%), and the lower extremities (22.0%). The upper extremities (8.9%), back (6.6%), and head and neck (6.1%) regions had relatively low frequencies of distribution. We identified the prevalence of eschar differed by geographic locations and anatomical sites on the patient of scrub typhus.