Approach

Treatment with antibiotics should be started if the diagnosis is suspected clinically. Delays in treatment have the potential to increase the severity of disease. Treatment should be continued for the recommended period of time if clinical response occurs in 48 to 72 hours, even in the absence of confirmatory tests.[122] Treatment of asymptomatic people who are seropositive for tickborne rickettsial diseases is not recommended.[68]

Antibiotic therapy

Treatment recommendations are based on empiric data.​[62][69][77][122]Ehrlichia chaffeensis and Anaplasma phagocytophilum are resistant to commonly used antibiotics such as penicillins, cephalosporins, macrolides, aminoglycosides, and quinolones.[123]​​[124]​​[125]​​[126][127]​​[128]​​[129]​​[130]​ However, response to tetracyclines (mainly doxycycline) is excellent in most cases, and relapse after successful therapy has never been reported.[69][77][122]​ Rifampin is a good second-line agent in patients who cannot tolerate tetracyclines or in whom tetracyclines are contraindicated.[123]​​[128]​​[129]​​[131]​ The use of chloramphenicol is no longer recommended based on in vitro susceptibility testing.

In the vast majority of cases, defervescence occurs 24 to 72 hours after treatment is started. The patient should be reevaluated if no improvement is seen after 72 hours of treatment.[122] However, in patients in whom the treatment is delayed for several days, improvement may take longer.

Adults

Doxycycline is recommended first line in adults.[21][68]​ Although it is not usually used in pregnancy, it can be used in serious or life-threatening cases. Tetracycline is less well tolerated than doxycycline and requires more frequent dosing. It is not recommended in pregnant women due to adverse effects on fetal osseous and dental development.[69][132] Rifampin may be used second line in patients who are allergic, or have other contraindications, to tetracyclines. Treatment course is at least 3 days after fever ends, usually 5 to 10 days.[68]

Children

Doxycycline is recommended first line in all children, regardless of age, as the risk of dental and osseous adverse effects is considered negligible with the short course of treatment used for this indication.[21][69]​​​​[133] Rifampin may be used second line in children allergic to doxycycline. Treatment course is at least 3 days after fever ends, usually 5 to 10 days.[68]

Pregnant women

Although doxycycline is not usually recommended in pregnancy, it can be used in cases that are considered life threatening. Alternatively, rifampin has been used with some success.[68]

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