Snapshot A 24-year-old man presents to his primary care physician for a rash. He had been hiking in Tennessee during a retreat at his new job last week. He reports that he pulled a tick off of himself, though he did not think much of it at the time. Since then, he has had fevers and headaches daily. A few days after the onset of fever, he developed a rash that started on his wrists and ankles and now has spread to his chest. On physical exam, there are small blanching erythematous macules on his chest and petechiae on his extremities. His palms and soles are spared. He is started on empiric antibiotics. (Rocky Mountain spotted fever) Introduction Classification login to view 17 more bullets Epidemiology login to view 7 more bullets Pathogenesis login to view 3 more bullets Prognosis login to view 3 more bullets Presentation Symptoms login to view 3 more bullets Physical exam Clinical Manifestations of Rickettsial Diseases Disease Vector Rash Eschar Regional Lymphadenopathy Rocky Mountain spotted fever (R. rickettsii) Tick Macular Petechial Purpuric Spreads centripetally (extremities to trunk) No No Mediterranean spotted fever (R. conorii) Tick Macular Papular Purpuric Yes No Rickettsialpox (R. akari) Mite Vascular Papular On trunk and extremities Yes Yes African tick bite fever (R. africae) Tick Vesicular Maculopapular Yes, multiple Yes Epidemic tyhpus (R. prowazekii) Louse Macular Papular Petechial Spreads centrifugally (trunk to extremities) No No Murine typhus (R. typhi) Flea Macular Papular Petechial Spreads centrifugally No No Scrub typhus (O. tsutsugamushi) Mite Macular Pale Yes Yes Studies Labs login to view 4 more bullets Skin biopsy login to view 1 more bullet Making the diagnosis login to view 1 more bullet Differential Q fever login to view 4 more bullets Treatment Management approach login to view 1 more bullet Medical login to view 6 more bullets Complications Neurologic sequelae Peripheral gangrene Reactive arthritis