What is Rocky Mountain Spotted Fever?

Rocky Mountain Spotted Fever (RMSF), is one of the deadliest tick-borne diseases in the world, killing as many as 10% of those infected. RMSF is a bacterial infection that is spread by a bite from an infected tick. If not properly treated RMSF may cause serious damage to organs and possibly even death. RMSF is more commonly found in the southeastern United States, Canada, Mexico, Central America and South America.

Number of U.S. SFR cases reported to the CDC, 2000–2017

What causes Rocky Mountain Spotted Fever?

RMSF is caused by a bite from a tick that is infected with the Rickettsia rickettsii bacteria or being exposed to material from a crushed tick. Once introduced to the body the bacterium spreads through your blood stream or lymphatic vessels and starts reproducing and causing damage inside living cells.

The red rods are Rickettsia Bacteria.

There are three known types of ticks that commonly carry Rickettsia rickettsii are.

American Dog Tick (Dermacentor variabilis)

Rocky Mountain Wood Tick (Dermacentor andersoni)

Brown Dog Tick (Rhipicephalus sanguineus)

What are the symptoms of Rocky Mountain Spotted Fever?

One of the classic symptoms of Rocky Mountain Spotted Fever is a distinctive rash that typically occurs after the fever, but 10-15% of patients do not develop a rash at all making diagnosing the infection more difficult.

Symptoms of RMSF typically start to appear between 2-14 days after being bitten by an infected tick. Symptoms may include:

Sensitivity to light

Stomach Pain
Muscle Pain
Lack of appetite

Is there testing and treatments available?

Yes, your doctor can order laboratory test to check for evidence of Rickettsia rickettsii. If Rocky Mountain Spotted Fever is strongly suspected doctors will go ahead and begin antibiotic before waiting for the results to come in.

RMSF is typically treated for 30 days with doxycycline but may require longer treatment.

More research is needed to determine if RMSF is reoccurring but patients and doctors have both described dealing with reoccurring RMSF.

According to a study published in the American Journal of Tropical Medicine and Hygiene, the Lone Star tick can carry a bacterium called Rickettsia amblyommi. This bacterium may cause a milder illness than RMSF. Blood test for Rocky Mountain Spotted Fever may come out positive if the test also identifies Rickettsia amblyommi leading to a misdiagnoses of RMSF but this information should not change treatment plans.

Because ticks can transmit mutiple infections doctor’s should also check for other Tick-borne illnesses and co-infections such as:

Alpha-Gal Syndrome

Can there be long term effects?

If Rocky Mountain Spotted Fever isn’t properly treated, it can cause damage to the lining of your blood vessels, tissues and organs. Other complications may include:

Inflammation of the brain that can lead to seizures and coma.

Inflammation of the heart.

Inflammation of the lungs.

Kidney failure.

Gangrene in the fingers or toes.

Enlarged liver or spleen.

Nerve Damage

Patients who have a severe case of RMSF may experience long-term health problems, such as:

Deafness or hearing loss

Partial paralysis

Neurological deficits

Muscle weakness

Some patients may develop a condition called Mast Cell Activation Syndrome.

Are there any online support groups for RMSF?

Yes, there are a couple online Facebook groups that you can join.

1. Mast Cell & Tick-Borne Disease awareness group.

2. Survivor’s of Rocky Mountain Spotted Fever.

3. Rocky Mountain Spotted Fever (RMSF) awareness.


Mayo Clinic Staff. (2014, September). Rocky Mountain spotted fever
▪ Rocky Mountain spotted fever. (2009)
▪ Rocky Mountain spotted fever. (2012)
▪Rocky Mountain spotted fever. (2016, June 8)

▪ Rocky Mountain spotted fever. (n.d.)
▪ Rocky Mountain spotted fever. (n.d.)
▪ Rocky Mountain spotted fever: Statistics and epidemiology. (2013, September 5)
▪ Rocky Mountain spotted fever: Symptoms, diagnosis, and treatment . (2010, September 5).
▪ Tickborne diseases of the United States: Rocky Mountain spotted fever. (2017, February)

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