The differential diagnosis for RMSF includes meningococcemia,
Staphylococcus aureus septicemia, other rickettsioses (ehrlichiosis,
murine typhus, epidemic typhus, rickettsialpox), leptospirosis,
typhoid fever, viral exanthem (measles, varicella, rubella, enterovirus,
parvovirus, adenovirus), hemorrhagic fevers (Ebola, Marburg, Lassa),
meningococcemia, chancroid, tularemia, syphilis, anthrax, ITP, drug
reaction, or an immune–complex-mediated vasculitis.