• Doxycycline is the treatment of choice for ehrlichiosis and all other tickborne rickettsial diseases. Presumptive treatment with doxycycline is recommended in patients of all ages, including children <8 years.
  • Doxycycline is most effective at preventing severe complications from developing if it is started within the first week of illness.

Treatment Duration

  • When treated with doxycycline, fever generally subsides within 24–48 hours.
  • Lack of a clinical response to doxycycline suggests that the patient’s condition might not be due to ehrlichiosis, or might be caused by other infections not responsive to doxycycline.
  • Resistance to doxycycline or relapses in symptoms after the completion of the recommended course have not been documented.
Recommended Treatment and Dosage for Ehrlichiosis

Doxycycline is the first-line treatment for adults and children of all ages:

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

Patients with suspected ehrlichiosis should be treated with doxycycline until at least 3 days after the subsidence of fever and until evidence of clinical improvement, typically 5-7 days.

Treating Children and Pregnant Women

  • The use of doxycycline to treat suspected rickettsial disease in children is standard practice recommended by both CDC and the American Academy of Pediatrics Committee on Infectious Diseases.
    • A recent study found that short courses of doxycycline (5–10 days) did not result in staining of permanent teeth or enamel hypoplasia. Use doxycycline as the first-line treatment for suspected ehrlichiosis in patients of all ages.
  • Use of antibiotics other than doxycycline increases the risk of severe illness and patient death.

Other Treatments

  • In cases of life-threatening allergies to doxycycline, severe doxycycline intolerance, and in some pregnant patients for whom the clinical course of ehrlichiosis appears mild, physicians might consider alternate antibiotics.
  • Rifampin appears effective against E. chaffeensis in a laboratory setting, but has not been evaluated as an alternative therapy in a clinical setting.
  • However, rifampin is not effective in treating RMSF, a disease that might be confused with ehrlichiosis.
  • Healthcare providers should be cautious when exploring treatments other than doxycycline, which is highly effective in treating multiple tickborne diseases including ehrlichiosis, anaplasmosis, Lyme disease, and Rocky Mountain spotted fever (RMSF).

Doxycycline as Prophylaxis

  • Post-tick bite antibiotic prophylaxis is not recommended to prevent ehrlichiosis.
  • People who have been bitten by a tick should watch for signs and symptoms. They should see their healthcare provider if fever, rash, or other symptoms develop within 2 weeks of tick bite.
  • Prophylactic treatment for tick bites is not currently recommended.

For more in-depth information about the recommended treatment for ehrlichioses, see: Diagnosis and Management of Tickborne Rickettsial Diseases: Rocky Mountain Spotted Fever and Other Spotted Fever Group Rickettsioses, Ehrlichioses, and Anaplasmosis — United States: A Practical Guide for Health Care and Public Health Professionals (2016 pdf icon[PDF – 48 pages]