Article in Japanese

A case of pediatric scrub typhus: early definitive diagnosis was achieved using eschar polymerase chain reaction

Ayano SHIRAI^1），Ryoki HARA^1），Yuki INAMI^1），Hironao MOTOI^1），Hiromi SHIOYA^1），Hiromi TADAKI^1），Tatsunori HOKOSAKI^1），Ayako FUKUYAMA^1），Yoichi KABURAGI^1）

Scrub typhus is a rickettsial infection caused by Orientia tsutsugamushi. Serodiagnosis，which is covered by insurance，has been used as a diagnostic method for scrub typhus for a long time，but in recent years，there have been reports of cases in which polymerase chain reaction (PCR) has been used to confirm the diagnosis. In this study，we report a case in which rickettsiosis was suspected based on a physical examination，and PCR tests (whole-blood and eschar PCR) were promptly submitted，which led to an early definitive diagnosis of scrub typhus.
The patient was a 6-year-old girl. An insect-bite-like rash appeared on her perineum a few days after engaging in outdoor activities，and she developed fever 14 days later. She was referred to our department on the 10th day of her illness because of a generalized skin rash and conjunctival hemorrhages in the eyes，and her symptoms did not improve. We suspected rickettsiosis due to her accompanying symptoms and recent history of engaging in outdoor activities. After the patient was admitted to our facility，we collected an eschar specimen from her and instructed her to begin taking minocycline hydrochloride. Then，her symptoms quickly improved. The results of the whole-blood and eschar PCR tests were reported 3 days after being submitted，and only the eschar specimen was positive for the Kawasaki strain. Based on our experience in this case，if rickettsiosis is suspected，we recommend performing early PCR tests，including an eschar PCR test，before the patient starts treatment.

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1） Department of Pediatrics，Yokohama Medical Center，National Hospital Organization

Key words	scrub typhus, early definitive diagnosis, PCR test, scab, serodiagnosis
Received	January 6, 2023
Accepted	March 9, 2023

35 (2)：143─149,2023