Rocky Mountain spotted fever is one of several diseases caused by the spotted fever group rickettsia, which are a type of bacteria. Other causes of spotted fever group rickettsioses (spotted fevers) in the United States include:
- Rickettsia parkeri rickettsiosis, caused by R. parkeri
- Pacific Coast tick fever, caused by Rickettsia philipii
- Rickettsialpox, caused by Rickettsia akari
These diseases have similar signs and symptoms, including fever, headache, and rash, but are often less severe than RMSF.