Severe fever with thrombocytopenia syndrome (SFTS) and scrub typhus describe similar clinical features; therefore, it is difficult to differentiate them. A recent study retrospectively collected data from 183 SFTS and 178 scrub typhus patients and validated an existing scoring system to develop a more sensitive, specific, and objective scoring system. It initially used the scoring systems given by Kim et al. to distinguish SFTS from scrub typhus. 

Multivariable logistic regression revealed a significant association of SFTS with altered mental status, leukopenia, prolonged activated partial thromboplastin time (aPTT), and normal C-reactive protein (CRP) level. 

The study modified the normal CRP level from ≤1.0 mg/dL to ≤3.0 mg/dL and replaced the altered mental status with the creatine kinase (CK) level. This study’s scoring system demonstrated 97% sensitivity and 98% specificity for SFTS and higher accuracy than Kim et al.’s original scoring system. 

This scoring system that incorporates leukopenia, prolonged aPTT, normal CRP level (≤3.0 mg/dL), and elevated CK level (>1000 IU/L) efficiently differentiates SFTS from scrub typhus in an endemic area.

Viruses. 2022; 14(5):1093. https://doi.org/10.3390/v14051093