What are the guidelines for managing scrub typhus?

Management Guidelines for Scrub Typhus

Doxycycline is the first-line treatment for scrub typhus and should be initiated promptly upon clinical suspicion to reduce complications and mortality. 1, 2

Diagnosis

• Look for characteristic clinical features:

  • Fever, headache, myalgia
  • Eschar at bite site (pathognomonic but not always present)
  • Regional lymphadenopathy
  • Maculopapular rash

• Laboratory confirmation:

  • Serological tests (IgM ELISA preferred)
  • PCR testing when available

Treatment Protocol

First-line Treatment

• Doxycycline:
  • Adults: 200 mg/day orally in two divided doses for 7 days 3
  • Alternative: Single 200 mg dose has shown efficacy in mild cases 4
  • Begin treatment immediately upon clinical suspicion, do not wait for serological confirmation 2

Alternative Treatments

• Azithromycin:

  • Single 500 mg dose has shown comparable efficacy to doxycycline for mild cases 5
  • Preferred for pregnant women and children <8 years 6
  • May have slightly longer time to defervescence compared to doxycycline 6

• Rifampicin:

  • 600-900 mg daily for 7 days
  • Consider in areas with doxycycline-resistant strains (particularly northern Thailand) 3
  • 900 mg dosing shows faster fever clearance (median 22.5 hours) compared to doxycycline (median 52 hours) in resistant areas 3

Management of Severe Cases

• Hospitalization for:
  • Respiratory distress
  • Altered mental status
  • Evidence of organ dysfunction
  • Hemodynamic instability
• Supportive care:
  • Intravenous fluids
  • Respiratory support as needed
  • Management of specific organ complications

Prevention

• Avoid mite bites in endemic areas:
  • Use insect repellents containing DEET
  • Wear protective clothing
  • Avoid sitting or lying on bare ground or grass
  • Treat clothing with permethrin in high-risk areas 1

Important Clinical Pearls

• Early treatment is crucial: Patients who receive doxycycline or azithromycin early in the course of illness have significantly fewer complications and lower mortality 2
• Do not delay treatment: Empiric therapy should be started based on clinical suspicion in endemic areas during mite season 2
• Monitor for complications: Even with appropriate treatment, monitor for development of pneumonitis, meningoencephalitis, acute kidney injury, and multiple organ failure 1
• Follow-up: Ensure clinical improvement within 48-72 hours of initiating treatment; consider alternative diagnoses or resistant strains if no improvement

Special Populations

• Pregnant women: Azithromycin is the preferred agent
• Children <8 years: Azithromycin is preferred over doxycycline due to risk of dental staining
• Areas with resistant strains: Consider rifampicin as first-line or in combination therapy

The evidence strongly supports early clinical suspicion and prompt initiation of appropriate antibiotic therapy as the most important factors in reducing morbidity and mortality from scrub typhus 1, 2.