Treatment for Anaplasmosis
Doxycycline is the treatment of choice for all patients with suspected or confirmed anaplasmosis, regardless of age or pregnancy status, and should be initiated promptly without waiting for laboratory confirmation. 1
First-Line Treatment
- Adults: Doxycycline 100 mg orally (or intravenously if unable to take oral medication) twice daily for 10 days 1
- Children: Doxycycline 4 mg/kg per day in 2 divided doses (maximum 100 mg per dose) orally or intravenously for 10 days 1
Clinical Response Expectations
- Patients typically show clinical improvement within 24-48 hours after starting doxycycline 1
- Failure to respond within 48 hours should prompt reevaluation for:
- Alternative diagnoses
- Coinfection (particularly with Babesia microti or Borrelia burgdorferi in endemic areas)
- Complications of anaplasmosis 1
Alternative Treatment Options
For patients with severe doxycycline allergy or pregnancy:
- Rifampin 300 mg orally twice daily for adults or 10 mg/kg twice daily for children (maximum 300 mg per dose) for 7-10 days 1
- Important caution: Rifampin should only be used when anaplasmosis is strongly suspected and Rocky Mountain Spotted Fever (RMSF) has been ruled out, as rifampin is not effective against RMSF 1
Contraindicated Treatments
The following antibiotics are ineffective or potentially harmful for anaplasmosis:
- Chloramphenicol (ineffective against anaplasmosis) 1
- Fluoroquinolones (may lead to relapse despite initial improvement) 1, 2
- Beta-lactams, macrolides, aminoglycosides, and sulfonamides 1
- Sulfonamides (may worsen disease severity) 1
Monitoring and Follow-up
- Close observation of clinical response is essential, particularly for patients treated with rifampin 1
- Monitor for resolution of:
- Fever
- Headache
- Myalgia
- Laboratory abnormalities (thrombocytopenia, leukopenia, elevated liver enzymes) 1
Special Considerations
Severe Disease
- Hospitalization may be required for severe cases
- Approximately 7% of hospitalized patients require intensive care 1
- Complications can include ARDS, peripheral neuropathies, coagulopathies, rhabdomyolysis, and opportunistic infections 1, 3
- In cases of anaplasmosis-induced hemophagocytic lymphohistiocytosis (HLH), combination of doxycycline with immunosuppressive therapy may be beneficial 3
Coinfections
- The tick vector (Ixodes scapularis/pacificus) can transmit multiple pathogens
- Consider coinfection with Borrelia burgdorferi or Babesia microti if response to treatment is delayed 1
- Doxycycline will treat both anaplasmosis and Lyme disease, but will not treat babesiosis 1
Prevention
- Prophylactic antibiotics after tick bites are not recommended for prevention of anaplasmosis 1
- Treatment of asymptomatic seropositive individuals is not recommended 1
Remember that early treatment is crucial to prevent complications and reduce mortality, which is less than 1% with appropriate treatment 4.