Rocky Mountain Spotted Fever
by Michelle Badash, MS
Rocky Mountain spotted fever (RMSF) is a severe infection. It can be deadly. It is spread through the bite of a tick.
The ticks are most common in North, Central, and South America.
RMSF is caused by a specific bacteria. An infected tick can spread it through a bite.
Risk Factors TOP
Factors that increase your chance of RMSF include:
The first symptoms of RMSF often occur within 2 to 14 days after a tick bite. Symptoms may include:
If left untreated, RMSF can cause severe problems. Other symptoms will depend on which organs are involved.
See your doctor if you have a fever after:
You will be asked about your symptoms and health history. A physical exam will be done. RMSF can be hard to diagnose. There are many conditions that cause similar symptoms. You may also be unaware of a tick bite. The rash may not be present yet.
The doctor may suspect RMSF based on your symptoms. A blood test may be done. They will help to find more signs of this infection.
A spinal tap may be done to look for infection around the brain.
Early treatment is important. Treatment may be started before all your tests come back.
RMSF is treated with antibiotics. Doxycycline is first choice. Make sure to take all of the medicine as advised.
Tick bites can cause a number of infections. If you are in an area that may have ticks:
Centers for Disease Control and Prevention
Family Doctor—American Academy of Family Physicians
Public Health Agency of Canada
The College of Family Physicians of Canada
Rocky Mountain spotted fever. EBSCO DynaMed Plus website. Available at: http://www.dynamed... . Updated June 4, 2015. Accessed February 15, 2018.
Rocky Mountain spotted fever (RMSF). Centers for Disease Control and Prevention website. Available at:
...(Click grey area to select URL)
Updated December 9, 2016. Accessed February 15, 2018.
Last reviewed March 2018 by EBSCO Medical Review Board David L. Horn, MD, FACP
Last Updated: 8/23/2018
EBSCO Information Services is fully accredited by URAC. URAC is an independent, nonprofit health care accrediting organization dedicated to promoting health care quality through accreditation, certification and commendation.
This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.
To send comments or feedback to our Editorial Team regarding the content please email us at firstname.lastname@example.org. Our Health Library Support team will respond to your email request within 2 business days.