Rocky Mountain spotted fever is a tick-borne infection caused by Rickettsia rickettsii that damages small blood vessels, most common in the southeastern and south-central US. It can kill quickly, so doxycycline is started on clinical suspicion without waiting for tests.
Key symptoms
- Sudden fever and severe headache
- Muscle aches, nausea, vomiting or abdominal pain
- Rash appearing 2 to 5 days after the fever
- Recent tick bite or outdoor activity, though many patients recall no bite
What you find on exam
- Small pink spots starting on the wrists and ankles, spreading to the trunk
- Rash on palms and soles that may turn into petechiae
- Swelling around the eyes or of the hands
- Confusion or low blood pressure in severe disease
Tests
- Clinical diagnosis; do not wait for tests to treat
- Low platelets, low sodium and high liver enzymes
- Paired antibody titers 2 to 4 weeks apart
- Skin biopsy PCR in some centers
Treatment basics
- Doxycycline for all ages, including young children
- Continue at least 3 days after the fever ends
- Hospital care with fluids and organ support if severe
- Prevention: repellent, protective clothing, daily tick checks
Red flags
- Confusion, seizures or coma
- Low blood pressure or breathing trouble
- Purple rash with skin death or bleeding
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; AAMC Core Entrustable Professional Activities (Core EPAs). Written by Making Synapses. Making Synapses is not affiliated with these organizations.