Rocky Mountain Spotted Fever Symptoms: Atypical Case and Missed Diagnosis
SYMPTOMS DON’T LOOK TYPICAL?
RMSF MAY BE MISSED
Can Rocky Mountain spotted fever symptoms be missed when they don’t follow the typical pattern?
Quick Answer: Rocky Mountain spotted fever (RMSF) symptoms can be atypical and difficult to recognize early. Delayed diagnosis is common when symptoms do not match classic expectations or when early test results are inconclusive.
Clinical Insight: Like many tick-borne illnesses, RMSF may present with nonspecific symptoms early in the course of illness. When symptoms evolve or do not respond as expected, clinicians must remain open to alternative diagnoses.
Rocky Mountain spotted fever symptoms can be atypical and challenging to diagnose. Although RMSF was initially identified in the Rocky Mountain region, cases are now reported throughout the nation, with higher incidence in the southeastern and south-central regions.
In their article, “Unconventional Rocky Mountain Spotted Fever Presentation From Kentucky: A Compelling Case Report and Literature Review,” Hussain and colleagues describe the case of a 71-year-old man who was admitted to the hospital with a fever, generalized weakness with myalgia, persistent hiccups, confusion, and agitation.
A physical exam revealed tachycardia, tachypnea, elevated blood pressure, and a high fever of 103.3°F. Test results showed severe hyponatremia, leukocytosis, and abnormal blood parameters.
Initial Treatment for Sepsis
The man’s Rocky Mountain spotted fever symptoms were initially attributed to sepsis.
His symptoms improved after he was treated with IV ceftriaxone for suspected sepsis due to a urinary tract infection or pneumonia.
However, the patient later developed a 106.5°F fever and required ICU admission.
“Upon further history-taking to determine the source of a fever of unknown origin, the patient revealed a potential exposure to ticks and a cat suspected of having lice one week prior.”
Testing for Tick-Borne Illness
He was subsequently tested for Bartonella, Borrelia burgdorferi, and Rickettsia (the bacterium that causes Rocky Mountain spotted fever).
As a precaution, the patient was treated empirically with doxycycline for a possible tick-borne illness and discharged.
Although initial testing was inconclusive, follow-up testing was positive for Rickettsia.
This type of delay reflects a broader pattern seen in tick-borne diseases, where early symptoms and test results may not clearly point to the diagnosis—similar to challenges described in delayed Lyme diagnosis.
Rocky Mountain Spotted Fever Symptoms – Key Points
- RMSF typically presents with fever, headache, rash, muscle pain, and nausea—but not all symptoms are present early.
- Test results are often normal in early disease, and confirmatory testing may take weeks.
- Atypical symptoms can include neurologic complaints, myocarditis, or visual disturbances.
When symptoms do not fit a clear pattern, diagnosis may be delayed—or alternative explanations may be considered first.
In some cases, patients may initially be treated for other conditions or told symptoms are unrelated before the correct diagnosis is made.
Clinical Perspective
This case highlights how atypical presentations can complicate diagnosis in tick-borne illnesses.
Early empiric treatment with doxycycline remains critical when RMSF is suspected, even if confirmatory testing is not yet available.
Maintaining clinical suspicion is essential—particularly when symptoms evolve or do not respond to initial treatment.
Frequently Asked Questions
What are typical Rocky Mountain spotted fever symptoms?
Fever, headache, rash, muscle pain, and nausea are common, but not always present early.
Is RMSF only found in the Rocky Mountain region?
No. Cases are reported nationwide, particularly in the southeastern and south-central United States.
How is RMSF diagnosed?
Diagnosis can be difficult early. Test results may be normal initially, and confirmation can take time.
How is RMSF treated?
Doxycycline is the treatment of choice. Early empiric treatment is critical to prevent severe complications.
Related Articles:
RMSF in Pregnancy: Atypical Case Without Rash
Tick bite leads to Rocky Mountain spotted fever
Fatal case of Heartland Virus
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References:
- Hussain A, Gray C, Marlowe S, et al. Unconventional Rocky Mountain Spotted Fever Presentation From Kentucky. Cureus. 2023.
Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.
Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention
In my twenties I had Rocky Mountain Spotted Fever from a nymph tick in New Jersey in 1989. It was undiagnosed til I went to a party with an infectious disease doctor who confirmed it. In my fifties I came down with four autoimmune diseases and two connective tissue diseases and now I’m quite sure I’m dealing with a Lysosomal Dusirder, Gaucher or Fabry Diseases as I also have POTS and EDS.
I had RMSF and went into psychosis from it. I was placed in an emergency psych facility for a week and my life fell apart as a result. My spouse divorced me and I lost my home and job. Doctors told me to apply for SSDI but I would have been homeless. I also have Hashimotos Encephalopathy so perhaps that triggered an autoimmune attack. I had a petachaie type rash on my chest and torso, stomach problems, myalgia, weakness, fatigue and joint pain, and also random fevers and mental confusion. I have tested positive twice for this despite being on Doxycycline. I now am on the Buehner protocol for it and feel great most days, most symptoms gone. If you think you have Lyme make sure to get on Doxycycline and the Buehner protocols as they will treat RMSF