What is the recommended treatment for scrub typhus?

Treatment of Scrub Typhus

Doxycycline is the drug of choice for treatment of 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

• Adults: Doxycycline 100 mg twice daily (orally or intravenously) for at least 3 days after fever subsides and until evidence of clinical improvement is noted; minimum treatment course of 5-7 days 1, 2
• Children <45 kg: Doxycycline 2.2 mg/kg body weight twice daily (orally or intravenously) 1
• Patients typically respond to appropriate antibiotics within 24-48 hours; lack of response within this timeframe should prompt consideration of alternative diagnoses 1, 3

Alternative Treatments

Azithromycin

• A single 500-mg dose of azithromycin has been shown to be as effective as a 1-week course of doxycycline for mild scrub typhus 4
• Recommended for pregnant women and children due to fewer adverse effects 5
• However, median time to fever clearance may be longer compared to other treatments 6

Rifampin

• Effective alternative, particularly in areas where doxycycline resistance has been reported 7, 5
• Dosage: 600 mg once daily for 5 days 7
• Studies have shown equivalent treatment effects and safety compared to doxycycline 7

Chloramphenicol

• Alternative when other options are not available 6
• May have faster clearance of fever compared to azithromycin 6

Clinical Considerations

• Treatment should never be delayed while awaiting laboratory confirmation, as delay can lead to severe disease, long-term sequelae, or death 1
• Mortality rates of up to 4% have been reported in untreated cases 3
• Doxycycline resistance has been documented in parts of northern Thailand, which may necessitate alternative treatments 5

Adverse Effects

• Doxycycline has more adverse events compared to azithromycin (RR = 0.47,95% CI: 0.31-0.71) 6
• The historical concern about dental staining in children under 8 years should not prevent the use of doxycycline for short courses of treatment 1
• Azithromycin has fewer side effects but may be more expensive 5

Treatment Duration

• Continue treatment for at least 3 days after fever subsides 1
• Minimum treatment course is typically 5-7 days 1
• Severe or complicated disease may require longer treatment courses 1

Prophylaxis

• Weekly doxycycline (200 mg) has shown 89% efficacy in preventing scrub typhus in high-risk exposure situations 8
• However, this approach may only suppress rather than prevent infection, as symptoms can appear after discontinuation of prophylaxis 8