A Case of Japanese Spotted Fever Showing Erythema Multiforme-like Eruption in Which Next-generation Sequencing Analysis was Useful for the Diagnosis

Abstract

A 57-year-old Japanese male visited to our department for high fever (> 38°C) lasting for 6 days with erythema multiforme-like rash on his extremities and trunk. He had pulmonary edema, and a laboratory test showed high CRP levels and elevated D-dimer. A blood culture was negative for facultative bacteria. Serological analysis with paired sera showed a slight elevation of IgG antibody titers specific for Japanese spotted fever (JSF). On the other hand, a PCR test of peripheral blood mononuclear cells was negative for JSF. The patient did not have any stab wound or skin rash typical of JSF. Since the test results were contradictory, we performed a next-generation sequencing analysis. As a result, specific genes for Rickettsia japonica were detected in peripheral blood mononuclear cells. Based on this result, we diagnosed the patient with Japanese spotted fever showing erythema multiforme-like eruption.