[Relapsing fever: an almost forgotten disease in focus again]. / Rückfallfieber.

Introduction | Relapsing fevers, transmitted by arthropods, are rarely encountered in Germany, thus they are often not considered as differential diagnosis in febrile patients. In the last months, more than fourty cases of louse-borne relapsing fever were diagnosed in asylum seekers in Germany. Some of the patients had to be admitted to intensive care units, one patient died despite therapy. Pathogen, disease and diagnosis | The causative agents are spirochetes of the genus borrelia, which can reach high densities in patient blood. Depending on the vector and the region, different species are prevalent worldwide. For diagnosis, appropriate techniques include direct detection by microscopy or PCR from EDTA-blood. Ordering such tests should not be delayed when there is suspicion for relapsing fever. Besides, malaria can also be excluded with microscopy of blood smears. Therapy | First-line antibiotics include tetracyclines and penicillin, acquired resistance has not yet been observed. Frequently patients develop a Jarisch-Herxheimer reaction shortly after initiation of therapy, requiring hospitalization or intensive care treatment. Managing the treatment exclusively in an outpatient setting is not recommended. Especially in migrants with febrile illness, relapsing fever is an important differential diagnosis.