What is the treatment protocol for scrub typhus?

Treatment Protocol for 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

• Adults: Doxycycline 100 mg twice daily (orally or intravenously) for at least 3 days after fever subsides and until clinical improvement is noted; minimum treatment course of 5-7 days 1, 2
• Children under 45 kg: Doxycycline 2.2 mg/kg body weight twice daily (orally or intravenously) 1, 3
• 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, 4

Alternative Treatments

• Azithromycin: Effective alternative, particularly for pregnant women and in cases of doxycycline allergy 4, 5

  • Single 500-mg dose has been shown to be as effective as a 1-week course of doxycycline for mild scrub typhus 6
  • May have longer time to defervescence compared to doxycycline (median 21 hours vs. 29 hours) but with fewer adverse effects 5, 6

• Rifampin: Effective alternative with equivalent treatment outcomes to doxycycline 7

  • Dosage: 600 mg once daily for 5 days 7
  • Particularly useful in areas with suspected doxycycline-resistant strains 7

• Other alternatives: Chloramphenicol, minocycline, ciprofloxacin, and roxithromycin have been used successfully 4, 8

  • Minocycline has shown faster defervescence than azithromycin in some studies 8

Special Populations

• Pregnant women: Azithromycin is the preferred treatment, with favorable pregnancy outcomes and no reported relapses 4
• Children under 8 years: The historical concern about dental staining should not prevent the use of doxycycline for short courses of treatment 1, 3
  • Recent studies found no evidence of dental staining or enamel hypoplasia among children who received short-term courses (≤21 days) of doxycycline 3

Treatment Duration and Monitoring

• Continue treatment for at least 3 days after fever subsides 1
• Minimum treatment course is typically 5-7 days 1
• Monitor for clinical response - most patients defervescence within 24-48 hours after initiating appropriate therapy 1, 6
• Severe or complicated disease may require longer treatment courses 1

Clinical Pearls

• Scrub typhus can cause disseminated vasculitic and perivascular inflammatory lesions resulting in significant vascular leakage and end-organ injury 4
• The characteristic eschar (a flat black crust at the site of the mite bite) is a valuable diagnostic clue but may not always be present 4
• Laboratory findings typically include leukopenia, thrombocytopenia, deranged hepatic and renal function, and proteinuria 4
• Without treatment, serious complications may occur involving multiple organs 4
• No relapses have been reported with appropriate treatment duration 6, 7