01
Suspect RMSF with fever, headache, and myalgia in the days to two weeks after a Dermacentor tick exposure.
02
The classic spotted rash starts on wrists and ankles around day 2-5 and may spread to palms and soles, but a third of cases never develop it.
03
Doxycycline is started empirically — do not wait for serology, which is often negative early.
04
Adult dose: 100 mg twice daily; pediatric dose: 2.2 mg/kg twice daily (max 100 mg/dose).
05
Continue at least 3 days after fever resolves and clinical improvement is clear, generally 7-14 days.
06
Mortality without treatment can exceed 20 percent; treated mortality is under 1 percent.