From the Guidelines
Intravenous doxycycline 100 mg twice daily is the recommended treatment for scrub typhus when oral administration is not possible, with a total treatment duration of at least 7 days. The treatment of scrub typhus, caused by Orientia tsutsugamushi, requires prompt initiation of antibiotics to reduce morbidity and mortality.
- The dose of doxycycline for adults is 100 mg per dose administered twice daily, which can be given orally or intravenously 1.
- For children weighing less than 100 lbs (45.4 kg), the dose is 2.2 mg/kg body weight per dose administered twice daily, also given orally or intravenously 1.
- Intravenous therapy is frequently indicated for hospitalized patients, while oral therapy is acceptable for patients who are early in the disease and can be managed as outpatients 1.
- The optimal duration of therapy has not been established, but current recommendations suggest treatment for at least 3 days after the fever subsides and until evidence of clinical improvement is noted, which is typically for a minimum total course of 5--7 days 1.
- Severe or complicated disease might require longer treatment courses, and patients should be monitored closely for signs of clinical improvement or complications.
- It is essential to note that doxycycline is bacteriostatic in its activity against rickettsial organisms, and its mechanism of action involves inhibiting bacterial protein synthesis by binding to the 30S ribosomal subunit to prevent Orientia tsutsugamushi replication.
- Supportive care, including IV fluids for hydration, antipyretics for fever, and monitoring for complications, is crucial in the management of scrub typhus.
- Treatment should begin immediately upon clinical suspicion without waiting for confirmatory tests, as delayed therapy increases mortality risk.
From the Research
Treatment Options for Scrub Typhus
- Doxycycline has proven efficacy in treating scrub typhus, although resistance has been documented in some areas 2
- Macrolides, such as azithromycin, are equally efficacious and have fewer adverse effects, but are more expensive 2
- Azithromycin is recommended for pregnant women and children 2
- Rifampicin is effective in areas where doxycycline resistance is present 2, 3
Severe Scrub Typhus Treatment
- Combination therapy with intravenous doxycycline and azithromycin may be a better therapeutic option for severe scrub typhus than monotherapy with either drug alone 4
- The use of combination therapy resulted in a lower incidence of composite primary outcome (death, persistent complications, and persistent fever) compared to doxycycline or azithromycin alone 4
- Further study is needed on the efficacy of different antibiotics in the treatment of severe, life-threatening scrub typhus 2, 5, 6
Antibiotic Comparison
- Tetracycline, doxycycline, azithromycin, and rifampicin are effective treatment options for scrub typhus, with few treatment failures 6
- Chloramphenicol is also a treatment option, but its use is limited due to the risk of adverse effects 6, 3
- The evidence for rifampicin is limited, and it should not be considered a first-line treatment option due to the risk of inducing resistance in undiagnosed tuberculosis 6