Clinical Care of Other Spotted Fever Rickettsioses

Key points

  • Doxycycline is the treatment of choice for all suspected rickettsial infections, including Rocky Mountain spotted fever (RMSF), Rickettsia parkeri rickettsiosis, Pacific Coast tick fever, and rickettsialpox.
  • Empiric treatment with doxycycline is recommended in patients of all ages, particularly when a life-threatening disease such as RMSF is suspected.
  • Treatment is most effective at preventing death and severe illness when doxycycline is started within the first 5 days of symptoms.
Doxycycline bottles

Treatment recommendations

Doxycycline is the first line treatment for adults and children of all ages, including pregnant people.

  • Adults over 45kg (100 lbs): 100 mg every 12 hours
  • Children under 45 kg (100 lbs): 2.2 mg/kg body weight given twice a day (maximum dose 100mg twice daily)

Patients should be treated for at least 5-7 days, and until 72 hours after the fever subsides and with evidence of clinical improvement.

Treating Children

The use of doxycycline to treat suspected rickettsial disease in children is recommended by both CDC and the American Academy of Pediatrics Committee on Infectious Diseases. If alternative antibiotics are considered, the choice of alternative antibiotic should be made after consulting with a specialist in infectious diseases.

Doxycycline prophylaxis is not recommended

Antibiotic prophylaxis after a tick bite is not recommended to prevent rickettsial infection. Persons who experience a tick bite should watch for symptoms suggestive of tickborne illness and consult a healthcare provider if fever, rash, headache, eschar, or other symptoms develop within 2 weeks of tick bite.


For more information on the recommended treatment of spotted fever rickettsioses, please read MMWR Recommendations and Reports.

Treatment timeline

When a patient is treated within the first 5 days of illness, fever usually resolves within 24-48 hours. In fact, failure to respond to doxycycline suggests that the patient's condition might not be caused by rickettsial infection. Severely ill patients may require longer periods before their fever resolves, especially if they have experienced damage to organ systems. Resistance to doxycycline or relapses in symptoms after the completion of the recommended course of treatment have not been documented.