Treatment of Scrub Typhus
Doxycycline is the drug of choice for treating scrub typhus in patients of all ages, including children under 8 years, and should be initiated immediately when scrub typhus is suspected. 1
First-Line Treatment Regimen
- For adults: Doxycycline 100 mg twice daily (orally or intravenously) for at least 3 days after fever subsides, with a minimum treatment course of 5-7 days 1
- For children under 45 kg: Doxycycline 2.2 mg/kg body weight twice daily (orally or intravenously) 1
- Treatment should never be delayed while awaiting laboratory confirmation, as delay can lead to severe disease, long-term sequelae, or death 1
- Patients typically respond to appropriate antibiotics within 24-48 hours; lack of response within this timeframe should prompt consideration of alternative diagnoses 1
Alternative Treatment Options
- Azithromycin (500 mg single dose) has shown efficacy comparable to doxycycline in treating mild scrub typhus 2
- Azithromycin is recommended for pregnant women and can be used successfully without relapse and with favorable pregnancy outcomes 3
- Rifampin (600 mg once daily for 5 days) may be considered an alternative treatment with equivalent efficacy to doxycycline, particularly in areas where doxycycline resistance has been reported 4, 5
- Macrolides are equally efficacious as doxycycline with fewer adverse effects, though they are more expensive 5
Clinical Considerations
- The historical concern about dental staining in children under 8 years should not prevent the use of doxycycline for short courses of treatment 1
- Doxycycline resistance has been documented in parts of northern Thailand, necessitating alternative treatments in those regions 5
- Most clinical evidence on drug treatment comes from cases of mild-to-moderate scrub typhus, with limited data on severe cases 5
- Scrub typhus causes disseminated vasculitic and perivascular inflammatory lesions resulting in significant vascular leakage and end-organ injury, making prompt treatment essential 3
Treatment Duration and Monitoring
- Continue treatment for at least 3 days after fever subsides 1
- The minimum treatment course is typically 5-7 days 1
- Severe or complicated disease may require longer treatment courses 1
- Monitor for clinical improvement, which typically occurs within 24-48 hours of initiating appropriate therapy 1