Highlights & Basics
- Rocky Mountain spotted fever (RMSF) can be fatal if not treated early.
- Signs and symptoms may be difficult to distinguish from those of common viral illnesses, leading to delayed diagnosis. Diagnosis should be considered in any person with a compatible clinical presentation and recent outdoor exposure.
- A characteristic eschar or scab at the site of the tick bite is absent, in contrast to infections due to other tick-borne spotted fever group rickettsiae. A history of tick bite may not be elicited in up to nearly one half of cases.
- Doxycycline is the drug of choice for treatment in patients of all ages and is almost always curative, especially if given in the first 5 days of illness. As the risk of death rises if appropriate therapy is not started before the fifth day of illness, doxycycline should be prescribed for suspected disease before confirmatory diagnostic test results are available.
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History & Exam
Key Factors
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Citations
Biggs HM, Behravesh CB, Bradley KK, et al. Diagnosis and management of tickborne rickettsial diseases: Rocky Mountain spotted fever and other spotted fever group rickettsioses, ehrlichioses, and anaplasmosis - United States. MMWR Recomm Rep. 2016;65:1-44.[Abstract][Full Text]
Centers for Disease Control and Prevention. Ticks: tickborne diseases of the United States. Mar 2025 [internet publication].[Full Text]
- CDC: preventing tick bites
- CDC: timeline of RMSF signs and symptoms
- CDC: rickettsial disease diagnostic testing and interpretation
- CDC: spotted fever rickettsiosis (including Rocky Mountain spotted fever) (SFR, including RMSF) 2020 case definition
- CDC: research - doxycycline and tooth staining
- CDC: about Rocky Mountain spotted fever
1. Biggs HM, Behravesh CB, Bradley KK, et al. Diagnosis and management of tickborne rickettsial diseases: Rocky Mountain spotted fever and other spotted fever group rickettsioses, ehrlichioses, and anaplasmosis - United States. MMWR Recomm Rep. 2016;65:1-44.[Abstract][Full Text]
2. Drexler NA, Dahlgren FS, Heitman KN, et al. National surveillance of spotted fever group rickettsioses in the United States, 2008-2012. Am J Trop Med Hyg. 2016;94:26-34.[Abstract]
3. Openshaw JJ, Swerdlow DL, Krebs JW, et al. Rocky Mountain spotted fever in the United States, 2000-2007: interpreting contemporary increases in incidence. Am J Trop Med Hyg. 2010;83:174-82.[Abstract]
4. Centers for Disease Control and Prevention. Ticks: tickborne disease surveillance data summary. Jul 2024 [internet publication].[Full Text]
5. Alvarez-Hernández G, Roldán JFG, Milan NSH, et al. Rocky Mountain spotted fever in Mexico: past, present, and future. Lancet Infect Dis. 2017 Jun; 17(6):e189-96.[Abstract]
6. Galvâo MA, Dumler JS, Mafra CL, et al. Fatal spotted fever rickettsiosis, Minas Gerais, Brazil. Emerg Infect Dis. 2003 Nov;9(11):1402-5.[Abstract][Full Text]
7. Bestul N, Padilla R, Montaño T, et al. Knowledge, attitudes, and practices on Rocky Mountain spotted fever among physicians in a highly endemic region-Mexicali, Mexico. Am J Trop Med Hyg. 2022 Oct 12;107(4):773-9.[Abstract][Full Text]
8. Salgo MP, Telzak EE, Currie B, et al. A focus of Rocky Mountain spotted fever within New York City. N Engl J Med. 1988 May 26;318(21):1345-8.[Abstract]
9. Centers for Disease Control and Prevention. Morbidity and mortality weekly report (MMWR): severe and fatal rocky mountain spotted fever after exposure in Tecate, Mexico-California, July 2023-January 2024. Nov 2024 [internet publication].[Full Text]
10. Demma LJ, Traeger MS, Nicholson WL, et al. Rocky Mountain spotted fever from an unexpected tick vector in Arizona. N Engl J Med. 2005 Aug 11;353(6):587-94.[Abstract][Full Text]
11. Lantos PM, McKinney R. Rickettsial and ehrlichial diseases. In: Cherry JD, Harrison GJ, Kaplan SL, et al, eds. Feign and Cherry's textbook of pediatric infectious diseases. 7th ed. Philadelphia, PA: Elsevier Saunders; 2014:2647-66.
12. Buckingham SC, Marshall GS, Schutze GE, et al. Clinical and laboratory features, hospital course, and outcome of Rocky Mountain spotted fever in children. J Pediatr. 2007 Feb;150(2):180-4, 184.e1.[Abstract]
13. Helmick CG, Bernard KW, D'Angelo LJ. Rocky Mountain spotted fever: clinical, laboratory, and epidemiological features of 262 cases. J Infect Dis. 1984 Oct;150(4):480-8.[Abstract]
14. Kirk JL, Fine DP, Sexton DJ, et al. Rocky Mountain spotted fever. A clinical review based on 48 confirmed cases, 1943-1986. Medicine (Baltimore). 1990;69:35-45.[Abstract]
15. Haynes RE, Sanders DY, Cramblett HG. Rocky Mountain spotted fever in children. J Pediatr. 1970 May;76(5):685-93.[Abstract]
16. Centers for Disease Control and Prevention. Rocky Mountain spotted fever (RMSF): clinical signs and symptoms. May 2024 [internet publication].[Full Text]
17. Traeger MS, Regan JJ, Humpherys D, et al. Rocky Mountain spotted fever characterization and comparison to similar illnesses in a highly endemic area-Arizona, 2002-2011. Clin Infect Dis. 2015 Jun 1;60(11):1650-8.[Abstract][Full Text]
18. Centers for Disease Control and Prevention. Ticks: tickborne diseases of the United States. Mar 2025 [internet publication].[Full Text]
19. Centers for Disease Control and Prevention. Rocky Mountain spotted fever (RMSF): clinical and laboratory diagnosis for Rocky Mountain spotted fever. May 2024 [internet publication].[Full Text]
20. US Department of Health & Human Services. Rickettsiosis subcommittee report to the tick-borne disease working group. Jan 2020 [internet publication].[Full Text]
21. Centers for Disease Control and Prevention. Spotted fever Rickettsiosis (including Rocky Mountain spotted fever) (SFR, including RMSF) 2020 Case Definition. 2020 [internet publication].[Full Text]
22. Centers for Disease Control and Prevention. CDC Yellow Book 2026: health information for international travel. Section 5: travel-associated infections and diseases - rickettsial diseases. Apr 2025 [internet publication].[Full Text]
23. Centers for Disease Control and Prevention. Rocky Mountain spotted fever (RMSF): clinical care of Rocky Mountain spotted fever. Mar 2025 [internet publication].[Full Text]
24. Lochary ME, Lockhart PB, Williams WT Jr. Doxycycline and staining of permanent teeth. Pediatr Infect Dis J. 1998 May;17(5):429-31.[Abstract]
25. Volovitz B, Shkap R, Amir J, et al. Absence of tooth staining with doxycycline treatment in young children. Clin Pediatr (Phila). 2007 Mar;46(2):121-6.[Abstract]
26. Todd SR, Dahlgren FS, Traeger MS, et al. No visible dental staining in children treated with doxycycline for suspected Rocky Mountain spotted fever. J Pediatr. 2015 May;166(5):1246-51.[Abstract][Full Text]
27. US Food and Drug Administration. Doxycycline use by pregnant and lactating women. Sep 2017 [internet publication].[Full Text]
28. Dahlgren FS, Holman RC, Paddock CD, et al. Fatal Rocky Mountain spotted fever in the United States, 1999-2007. Am J Trop Med Hyg. 2012 Apr;86(4):713-9.[Abstract]
29. Holman RC, Paddock CD, Curns AT, et al. Analysis of risk factors for fatal Rocky Mountain spotted fever: evidence for superiority of tetracyclines for therapy. J Infect Dis. 2001 Dec 1;184(11):1437-44.[Abstract][Full Text]
30. Hattwick MA, Retailliau H, O'Brien RJ, et al. Fatal Rocky Mountain spotted fever. JAMA. 1978 Sep 29;240(14):1499-503.[Abstract]
31. Archibald LK, Sexton DJ. Long-term sequelae of Rocky Mountain spotted fever. Clin Infect Dis. 1995 May;20(5):1122-5.[Abstract]
