What is the recommended treatment for a patient diagnosed with scrub typhus?

Scrub Typhus Management

First-Line Treatment

Doxycycline is the drug of choice for scrub typhus and should be initiated immediately upon clinical suspicion without waiting for laboratory confirmation. 1

Dosing Regimens

• Adults: Doxycycline 100 mg twice daily (oral or intravenous) for a minimum of 5-7 days, continuing for at least 3 days after fever subsides with evidence of clinical improvement 1, 2

• Children under 45 kg: Doxycycline 2.2 mg/kg body weight twice daily (oral or intravenous) 1

• Children 45 kg or older: Use adult dosing of 100 mg twice daily 1

Route Selection

• Intravenous therapy is indicated for hospitalized patients who are vomiting, obtunded, or have severe disease 1

• Oral therapy is acceptable for patients early in disease course who can be managed outpatient, or for stable inpatients who are not vomiting 3, 1

Expected Clinical Response

Fever typically subsides within 24-48 hours after initiating doxycycline when treatment is started during the first 4-5 days of illness. 3, 1

• Failure to respond within 48 hours should prompt consideration of alternative diagnoses 3, 1

• Severely ill patients with multiple organ dysfunction may require longer periods before clinical improvement is noted 3

Critical Management Principles

Immediate Treatment Imperative

• Treatment must never be delayed while awaiting laboratory confirmation, as delay can lead to severe disease, long-term sequelae, or death 1

• Initiate therapy based on clinical suspicion when history, physical examination findings (fever, rash, eschar), geographic location, and laboratory abnormalities (thrombocytopenia, leukopenia) are compatible with scrub typhus 3

Pediatric Considerations

• The historical concern about dental staining in children under 8 years should not prevent doxycycline use for short courses, as limited tetracycline use during the first 6-7 years of life has negligible effect on permanent tooth color 1

• The American Academy of Pediatrics identifies doxycycline as the drug of choice for rickettsial diseases in all children, including those under 8 years of age 1

Alternative Agents (When Doxycycline Cannot Be Used)

While doxycycline remains first-line, research has demonstrated equivalent efficacy for:

• Azithromycin: Single 500 mg dose showed 100% cure rate with median defervescence time of 21 hours in mild scrub typhus 4

• Rifampin: 600 mg once daily for 5 days showed equivalent treatment effects to doxycycline in areas without documented resistance 5

• Telithromycin: 800 mg once daily for 5 days demonstrated equivalent efficacy and safety to doxycycline 6

These alternatives may be considered when doxycycline is contraindicated or in areas with documented doxycycline resistance 4, 5, 6

Common Pitfalls to Avoid

• Never calculate dose based on age alone—always use actual body weight, and verify syrup concentration before calculating mL doses to prevent underdosing 1

• Do not discontinue treatment prematurely—continue for at least 3 days after fever resolution and ensure the minimum 5-7 day total course is completed 1

• Do not withhold treatment in children under 8 years due to dental staining concerns, as this outdated practice can lead to preventable morbidity and mortality 1

• Do not delay treatment for serologic confirmation, as serology results typically take 3 days and early treatment is critical for optimal outcomes 3

Hospitalization Criteria

At least 50% of patients with tickborne rickettsial diseases require hospitalization 3. Admit patients with:

• Evidence of organ dysfunction 3
• Severe thrombocytopenia 3
• Mental status changes 3
• Need for supportive therapy or intravenous medications 3