Symptoms and Signs of Rocky Mountain Spotted Fever

Medical Author:
Medically Reviewed on 10/7/2022

Doctor's Notes on Rocky Mountain Spotted Fever

Rocky Mountain spotted fever (RMSF) is an illness caused by the bacteria Rickettsia rickettsii that is transmitted to humans by an infected tick bite. RMSF is the most common fatal tickborne disease in the U.S.

Early symptoms of Rocky Mountain spotted fever are nonspecific and may be mistaken for other illness so it is important to alert a doctor that a tick bite has occurred. Symptoms and include 

About two days to two weeks after the tick bite occurs, symptoms including 

The rash usually begins on the wrists and ankles and spreads to the palms and soles of the feet. Other symptoms of Rocky Mountain spotted fever may include

  • loss of appetite,
  • hallucinations,
  • sensitivity to light,
  • eye redness, and
  • excessive thirst.

If RMSF is not promptly diagnosed and treated, severe symptoms may develop including 

What is the treatment for Rocky Mountain Spotted Fever?

The CDC recommended treatment is the antibiotic doxycycline for RMSF. It is suggested that if a person is even suspected to have RMSF, the antibiotic should be administered empirically for adults and children of all ages due to the possible tissue and/or organ damage that may occur. However, pregnant patients may be prescribed the antibiotic chloramphenicol instead of doxycycline. 

Early treatment within 5 days of infection may avoid complications seen in serious infections.

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Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.